Typhoons are among the most significant natural disasters affecting the eastern and southern coastal regions of China, inflicting substantial annual damage on both coastal and inland areas. Since the initiation of the reform and opening-up policy, the socioeconomic development of the coastal regions of China has been swift, leading to increased exposure to typhoons. In the context of global climate change, typhoons are expected to increase in frequency and intensity in China. Therefore, researching on the spatiotemporal pattern characteristics of typhoons impacting China is of critical importance for understanding the impact patterns and risk changes of typhoon disasters, as well as for formulating policies on disaster response, prevention, and mitigation. This study aims to provide valuable insights into the formulation of such policies. Based on these objectives, this study utilized a comprehensive dataset, including county-level socioeconomic and disaster statistics, historical typhoon wind and rainfall data, and high-precision topographic data. Using county-level administrative regions as spatial units, this study employed various methods, such as time-series statistical analysis, gravity model, geographical detector, spatial correlation analysis, and geographically weighted regression, to analyze the spatiotemporal distribution patterns and influencing factors of typhoon disaster conditions in China from 1978 to 2020. The findings of this study are as follows: (1) The number of deaths and missing persons, quantity of damaged housing, death, and missing rate per million people, and proportion of direct economic loss to GDP caused by typhoon disasters have all shown a declining trend, indicating significant achievements in disaster prevention and mitigation efforts. (2) The center of gravity of typhoon disaster-related losses has shifted southward, corresponding with the economic development of coastal regions, demonstrating a reduced disaster impact in coastal areas and an increased impact in inland areas. (3) Wind and rain induced by typhoons are the primary driving factors of disaster conditions, and topographical factors are also drivers of casualties and crop loss. (4) The two major regions, Zhejiang-Northern Fujian and Western Guangdong-Eastern Guangxi, exhibit significant characteristics of disaster condition agglomeration, closely related to typhoon activity patterns and levels of economic development. (5) There is a negative correlation between the gross local product and disaster conditions in some areas, reflecting the role of socioeconomic development in enhancing the capacity for disaster prevention and mitigation.

Against the backdrop of rapid global climate change, the frequency and severity of storm surges in coastal areas are increasing, particularly in tidal river segments that are affected by storm surges and upstream river flooding. Although existing storm surge models have introduced a variety of different boundary settings, the boundary conditions provided are limited and cannot meet the current generalization needs of complex hydraulic engineering projects in China. This study considered the Feiyun River Basin as the research subject and coupled the upstream hydrodynamic model IFMS with the oceanic storm surge model ADCIRC. By utilizing the strengths of both models, a flood evolution model for the estuarine tidal river segment was established, enabling the spatiotemporal simulation of tidal levels in the Feiyun River tidal segment. The model not only effectively considers the impact of storm surge propagation at the estuary on flood evolution in the tidal river segment, but also the effect of upstream river flooding on the area. The study first validated the model with Typhoon Meranti in 2016, where the simulation results showed a high degree of agreement with the observed data series and errors were within acceptable limits. Flood processes at the Ruian, Mayu, Bishan Liqiao, and Dongtou tidal stations during Typhoons Doksuri and Khanun were simulated. The results show that the peak flood errors at all four stations were below 0.30 m, with Nash coefficients >0.80, indicating the model's capability to accurately reflect tidal level fluctuations and effectively contribute to disaster prevention and mitigation efforts in estuarine tidal segments. Finally, the study analyzed the impact of the driving forces of the upstream and downstream boundaries on tidal level predictions at three stations (Ruian, Mayu, and Bishan Liqiao). It was concluded that, compared to Mayu and Bishan Liqiao stations, the influence of the upstream boundary on Ruian can essentially be ignored, suggesting that the error from the upstream boundary under the influence of Typhoon Khanun is negligible for predicting errors at Ruian. The degree of the impact of the downstream boundary fluctuations on the three stations, from largest to smallest, was Ruian, Bishan Liqiao, and Mayu. Compared to the changes in the upstream boundary, the downstream boundary had a greater overall impact on all three stations. Additionally, when the downstream boundary changed by the same magnitude, the variation in low tide levels showed a decreasing trend from downstream to upstream, whereas the variation in high tide levels, although following the same trend, did not show a significant difference between the three. In summary, compared to the upstream boundary, the downstream boundary had a greater impact on tidal-level predictions at the three stations. The result shows that the lower boundary has a greater impact on the tidal level forecasts at three stations compared to the upper boundary. The study not only provides a new method for tidal river flood simulation in coastal urbanized areas but also offers directions for improving model simulation accuracy through analysis.

Islands are sensitive zones of sea-land interaction and typical ecologically fragile areas that are highly vulnerable to natural disasters, especially marine aquaculture, which is sensitive and at high risk to typhoon disasters; additionally, they are home to aquaculture households with high economic vulnerability to typhoons and poor adaptive capacity. This study focused on Liuheng Town of Zhoushan and the Dongtou District of Wenzhou, which were severely affected by Super Typhoon Lekima, and Gouqi Town of Zhoushan, which was severely affected by Typhoon In-Fa and Super Typhoon Chanthu, as case areas. Based on data acquired from 344 questionnaire surveys of aquaculture households and interview data from various related bodies, this study used factor analysis of mixed data and hierarchical clustering on principal components to identify the types of vulnerability of island aquaculture households to typhoon disasters and reveal the characteristics of each vulnerability type, as well as to identify the discriminative indicators of household vulnerability types, for analyzing the impact of typhoon disasters and other stressors on the vulnerability of island aquaculture households to typhoons. The results showed that the aquaculture industry and aquaculture households in the island areas showed high economic vulnerability, with most shrimp, crab, and shellfish mixed farming, algae, and mussel farming households suffering serious losses from typhoons. Second, differences in exposure, sensitivity, and adaptive capacity led to three different types and characteristics of vulnerability in aquaculture households. The degree of household exposure varied across aquaculture species, with mussels having the highest, algae the next highest, and shrimp, crab, and shellfish the lowest. Island aquaculture households showed outstanding sensitivity, as reflected in their high dependence on aquaculture, significant household human capital problems, relatively limited support from social networks, and frequent exposure to typhoon disasters. The adaptive capacity of households varied across aquaculture species, with mussel households having superior adaptive capacity, and shrimp, crab, and shellfish households and algal aquaculture households having relatively poor adaptive capacity. Third, the common influencing factors of aquaculture households' vulnerability to typhoon disasters are labor shortages, frequent typhoon disasters, and inadequate infrastructure. The differences among the significant discriminant indicators, such as the degree of exposure, aquaculture species, average annual household income, age and education level of the household head, social support, number and type of adaptation strategies adopted, and cost–benefit situation, are key to the formation of different vulnerability types. Finally, multiple stressors from the climate, ecosystem, economy and markets, society, institutions, and policies mutually interact to exert cumulative effects that increase the vulnerability of fishery ecosystems and the socioeconomic vulnerability of households in island regions. This study provides important empirical evidence for governments, aquaculture households, and other relevant stakeholders in island regions to reduce their vulnerability and increase their adaptive capacity.

The dynamic risk assessment of typhoon disasters is an important decision-making basis for disaster response in the event of a major typhoon. Its goal is to dynamically predict the expected loss and disaster risk level caused by a typhoon so as to provide a basis for disaster risk early warning and emergency response. The traditional risk assessment model mainly fits the vulnerability curves of the hazard-affected bodies using historical disaster losses, and then establishes a disaster risk assessment model by coupling the risk of disaster factors, exposure, and vulnerability. However, the vulnerability curves generated by this method have problems of regional applicability, particularly in small-scale regions with small sample sizes available for fitting, leading to insufficient generalizability of the model. In addition, such models are complex and require phased hazard and vulnerability of the hazard-affected bodies research. Moreover, when employing the 3-element coupling process, it is difficult to consider other risk factors in the disaster system, such as hazard-formative environment and disaster prevention and mitigation capability. With the development of information technology, the availability of disaster risk factor data has been significantly improved, affording conditions for the fusion and application of disaster risk multi-source data. In recent years, many data-driven machine-learning models have been used to establish disaster risk assessment models. These models have the advantage that they can use large sample to improve the adaptability of the model, whereby the modeling process can consider more risk factors, the concepts of hazard and vulnerability are diluted, and the steps of model building are simplified. The integrated learning algorithm can not only improve the prediction accuracy, but more importantly, can be used to effectively evaluate the contribution value of the index to the final evaluation result. At present, China has established a six-level disaster reporting system at the national, provincial, municipal, county, township, and village levels, forming a long-term, high-precision database of disaster event cases since 2009, providing rich disaster loss information for the data fusion of risk elements. This study was based on 108 typhoon cases affecting five provinces in southeast China during 2009-2022. Nearly 4,000 county-level typhoon disaster loss samples were used to establish a dynamic typhoon risk assessment sample database that integrates 30 types of multi-source risk factor indicators. Six typhoon disaster risk assessment models were developed using the random forest algorithm to evaluate the affected population, emergency relocation population, crop-affected areas, collapsed and severely damaged houses, direct economic losses, and comprehensive risk level. Through the verification of actual disaster situations and model results, the overall accuracy of the disaster risk assessment results was found to be greater than 80%, indicating that the model has good generalizability and can be used for actual disaster assessment work. The experimental comparison shows that increasing the training sample size by 1-2 orders of magnitude can improve the accuracy of the model assessment by 3%-14%, indicating that the accumulation of disaster risk big data is of great significance in the study of disaster risk assessment. This study is expected to constitute a scientific reference for the quantitative analysis of the multiple impact factors of typhoon disaster damage and explore technical ideas for the application of disaster big data in risk management.

Social and economic losses from typhoons are increasing owing to climate change. It is of practical significance to correctly understand new characteristics and trends in typhoon activity. Based on the best track dataset of tropical cyclones from the China Meteorological Administration, the temporal and spatial variation characteristics and evolution law of northward-moving typhoons from 1949 to 2022 were analyzed using the linear trend, Mann-Kendall test, and wavelet analysis method, and the impacts of the El Niño-Southern Oscillation (ENSO) on typhoon activities were also discussed. The results showed that: (1) 275 northward-moving typhoons occurred during the past 74 years, with an average of 3.7 per year. The interannual fluctuation in typhoon frequency was large, and the upward trend was not significant. The proportion of northward-moving typhoons to the total number of generated typhoons in the Northwest Pacific was between 2% and 30%, showing a significant upward trend. (2) Northward-moving typhoons were mainly generated from July to September, accounting for approximately 88.4% of the total typhoons. The highest number of typhoons entering the defined area was 114 in August. The life-cycle intensity of northward-moving typhoons is dominated by high-intensity grades, such as super typhoons and typhoons. Among them, super-typhoons accounted for 30.5% of the total number of northward-moving typhoons, and the intensity of typhoons and above grades exceeded 70% of the total amount. In recent years, the probability of high-intensity northward-moving typhoons has increased. (3) A total of 159 northward-moving typhoons landed in China over 74 years. Most of the turning-track typhoons made landfall in Taiwan, Fujian, and Zhejiang, whereas the landing locations of landed disappearing-track typhoons made landfall more northerly. Most unlanded turning-track typhoons turned eastward near 30°N and 125–130°E, showing a significant upward trend. The generating positions of the northward-moving typhoons were mainly concentrated in the ranges of 10—20°N and 130—150°E, with a density of 4.65/10,000 km². The central generation position of the landed northward-moving typhoons was 4.2° more westward than that of the unlanded typhoons. The latitude of the central generating position of the disappearing typhoons was 2.1° northward compared to that of the turning typhoons. (4) The Niño3.4 index had significant negative and positive correlations with the frequency and life-cycle intensity of northward-moving typhoons, respectively, and it also had an obvious effect on their generating positions. There were 4.5 northward-moving typhoons in the La Niña year, which was 1.67 times the El Niño year. However, the intensity of northward-moving typhoons generated during El Niño years was significantly higher than that generated during La Niña years, and the intensity of northward-moving typhoons increased with the Niño3.4 index. The central generating position of northward-moving typhoons during La Niña years was 5.8° northward and 12.4° westward compared to that during El Niño years, which was closer to China. This study provides a basis and reference for strengthening the risk management of typhoons and improving the efficiency of disaster prevention and reduction.

Typhoon gales can lead to accidents such as the breakage and collapse of transmission line towers, affecting the operational safety of power systems. Therefore, the risk assessment of transmission line towers during typhoon disasters is important. Taking all transmission towers in Zhejiang Province as an example, a typhoon disaster vulnerability assessment model for transmission line towers based on "excess loss" for both continuous and discrete variables was proposed based on tower attributes, geographical information, and typhoon disaster data. Utilizing the reanalysis data of typhoon parameters and wind fields from the past 68 years, a typhoon gale hazard assessment model was established based on the extreme value theory, and the statistical parameters of wind speed intensity under typical scenarios were analyzed. Furthermore, based on the regional disaster system theory and through a coupling analysis between typhoon gales and tower vulnerability, a risk assessment model for typhoon transmission line towers was developed. The results indicate the following: (1) the hazard of typhoon gales decreases from southeast to northwest, with differentiated distributions due to the local terrain and other factors. As the return period increased, a nonlinear increasing trend was observed. Taking the maximum wind speeds with a return period of 20 years and 100 years as examples, the wind speed intensities across Zhejiang Province range from 23.5-50.9 m/s and 32.6-68.9 m/s, respectively. Therefore, different wind resistance strategies should be adopted based on specific prevention requirements. Notably, the typhoon parameter wind field model used in this study had certain errors compared to the actual measured wind speeds. Therefore, in practical applications, particularly in complex terrain areas, it is necessary to combine local observational data for model calibration and application. (2) The comprehensive vulnerability of towers under the influence of typhoons generally exhibits a distribution pattern that is high in the south and low in the north, which is closely related to the terrain. Regions with high vulnerability (>1) were mainly located in central and southern Zhejiang and the coastal areas. Moderate vulnerability (0.5-1) is distributed in the Jinqu Basin and the offshore areas from Taizhou to Ningbo. The northeastern plain of Zhejiang had a relatively low tower vulnerability (<0.5). (3) The risk of transmission line towers generally exhibits a pattern of being high in the south and low in the north, with higher risks along the coast and lower risks in inland areas. There are significant local differences. In southeastern Wenzhou, Taizhou, and southern Lishui, the risk level of the towers was the highest. The southern part of Ningbo, Zhoushan, western Quzhou, and eastern Jinhua had the second highest risk. Additionally, some areas in Shaoxing, Huzhou, and Hangzhou have towers with higher risks that need to be addressed, which is consistent with the actual investigation findings. These results provide the necessary technical support for disaster risk assessments. Risk management plans should be adopted based on regional differences.

In the context of climate change, the escalating frequency of extreme weather phenomena has exacerbated the severity of compound floods in the southeastern coastal regions of China. Rising sea levels significantly contribute to the inundation of low-lying coastal urban areas. The quantitative assessment of compound flood risk offers scientific support for disaster prevention and reduction in coastal cities and for coastal management initiatives. Using Haikou City as a case study, the daily precipitation and maximum storm surge tide data from 66 typhoons that affected Haikou between 1960 and 2017 were utilized to construct compound flood combination scenarios. Based on the quantitative method of D-Flow FM (Delft3D-FLOW Flexible Mesh) numerical simulation, the potential risks of extreme rainfall and storm surge compound flood disasters under sea level rise scenarios were thoroughly investigated by integrating various scenarios. The findings revealed the following: 1) Storm surge was the primary factor contributing to compound flooding during typhoons, with the estuary of the Nandu River and the northern coast being the most affected. 2) In the scenario of maximum rainfall and storm surge combination, the inundation area of Haikou is about 148 km², which is approximately 15 times larger than the minimum rainfall and storm surge combination scenario. Moreover, in more than half of the inundated areas, the water depth exceeds 1 meter. 3) Under extreme rainfall and storm surge compound scenarios, the areas encompassing Haidian Island, Xinbu Island, and Jiangdong New Area were significantly affected by sea level rise. By 2100, the total flooding area is projected to reach about 203 km² under the RCP8.5 scenario. Sea level rise significantly amplifies urban flood risks, implying that coastal cities are poised to encounter heightened threats and manage future challenges. Through comprehensive comparisons of multiple rainfall and storm surge compound flooding scenarios under sea level rise, the temporal and spatial characteristics of the compound flooding risk were systematically evaluated. The results provide an important scientific basis for sustainable regional development, effective management, and prevention.

Typhoons are extreme weather phenomena that seriously affect the daily lives of residents and regular functioning of society. As one of the most typhoon-prone countries in the world, China is constantly affected by typhoons and their secondary disasters, which can cause significant casualties and economic losses. The extent of damage caused by typhoons is inversely proportional to the effectiveness of the emergency response. Therefore, accurate and comprehensive access to damage information is critical for rescue and recovery. Social media, which is characterized by low collection costs and rich content, is an important means of collecting disaster information. With the development of social media, it has become increasingly important to accurately and comprehensively identify social media texts related to typhoons. In this study, by combining typhoon attribute data and a multi-label classification method with Bidirectional Encoder Representations from Transformers (BERT) and Bidirectional Long Short-Term Memory (BiLSTM) models, a typhoon damage identification method based on Weibo texts and deep learning is proposed to identify the damage caused by severe and super typhoons that made landfall in Guangdong Province from 2010 to 2019. First, texts related to typhoon damage were identified from the massive Weibo texts and further classified into five damage categories: transportation, public, electricity, forestry, and waterlogging. The typhoon damage characteristics were comparatively analyzed using spatial distribution, time curves, and quantity curves. The results showed that the accuracy of typhoon damage classification was high, with an F1 score of 0.907 for identifying typhoon damage-related texts and 0.814 for further classifying them into five damage categories. Typhoon attribute data and multi-label classification methods have improved the accuracy and comprehensiveness of typhoon damage identification. Compared to the use of Weibo texts only and the single-label classification method, typhoon attribute data provide information on the geographic context of the typhoon at the time of the texts' release, and the multi-label classification method allows the texts to belong to more than one damage category. This study shows that there are differences in the proportion of damage caused by different typhoons, which are related to the intensity and track of the typhoon, as well as the development level of the affected areas. In addition, before the typhoon makes landfall, precautions lead to transportation and public-related damage. After the typhoon makes landfall, the typhoon damage shows single and double-peak characteristics, and the different characteristics reflect the changing trends and features of typhoon damage. This study provides a scientific basis for typhoon damage identification and disaster relief in Guangdong Province.

Rainfall and sea surface temperature grid data, as well as rainfall data from coastal stations in China, were used to obtain the spatiotemporal response characteristics of summer rainfall along the Chinese coast to ENSO and analyzed interdecadal changes in summer rainfall. The results show that: (1) Summer rainfall along the coast of China was significantly affected by ENSO and can be divided into three regions, with Lianyungang and Yunao as the boundaries. The Niño3.4 index was negatively correlated with summer rainfall along the Bohai and Yellow Sea coasts, positively correlated with that of the East China Sea coast, and not significantly correlated with that of the South China Sea coast. (2) On an interdecadal timescale, the relationship between summer rainfall along the coast of China and the Niño3.4 index was unstable. The negative correlation between summer rainfall along the Bohai and Yellow Sea coasts and the Niño3.4 index was significant before and after 1980 and 2010, respectively. The positive correlation along the East China Sea coast became insignificant after the 1980s, whereas the correlation along the South China Sea coast remained insignificant. (3) On the interdecadal timescale, the summer Niño3.4 index, winter Arctic Oscillation (AO) index in the previous year, and spring Antarctic Oscillation (AAO) index in current year were significantly negatively correlated with summer interdecadal rainfall along the Bohai and Yellow Sea coasts and positively correlated with summer interdecadal rainfall along the East China Sea coast. Summer interdecadal rainfall along the coast of the South China Sea was significantly negatively correlated with the spring Arctic Sea ice index in the current year. Regarding the Niño3.4 index, the high sea surface temperature in the Central and Eastern Pacific triggered a negative Pacific-Japan-type interconnection wave train in the 500 hPa geopotential height field, resulting in a decrease in interdecadal rainfall along the Bohai and Yellow Sea coast and an increase in interdecadal rainfall along the East China Sea coast. When the winter AO in the last year and spring AAO in the current year were in a positive phase, the abnormal anticyclone in the southern part of Baikal Lake at 850 hPa wind field guided the airflow in the mid to high latitudes southward, causing a weakening of the East Asian summer monsoon and a decrease in interdecadal summer rainfall along the Bohai and Yellow Sea. In addition, the strong, westward position of the subtropical high pressure in the northwest Pacific increases the upward movement, increasing interdecadal summer rainfall along the East China Sea coast. The interdecadal variation of spring Arctic Sea ice stimulates the opposite atmospheric circulation pattern that induced interdecadal variation of summer rainfall along the South China Sea coast in the 850 hPa wind and 500 hPa geopotential height fields.

Catastrophe insurance is an important financial tool to mitigate the risk of catastrophes. After the 2008 Wenchuan Earthquake, China accelerated its exploration of a catastrophe insurance system. As one of the most natural disaster-prone provinces in China, Guangdong experiences frequent rainstorms and typhoons. Severe natural disasters have not only led to significant losses to economic development and people's lives, but have placed considerable financial pressure on governments at all levels. To promote the transformation of government functions and use of catastrophe insurance as a modern financial tool to cope with major natural disasters, Guangdong has conducted pilot work since 2016 to explore and experiment with different aspects of catastrophe index insurance. This includes the design and application of insurance systems and products. The pilot work achieved remarkable results and formed the Guangdong catastrophe index insurance paradigm. However, few studies have examined the development and application of catastrophe index insurance programs in Guangdong Province. This paper describes the research and design process, data, and key methods of typhoon catastrophe index insurance in Guangdong, in accordance with the specific catastrophe index insurance practices. Furthermore, the application of the current catastrophe index insurance program from 2016 to 2023 is reviewed. Additionally, the advantages, characteristics, and shortcomings of the program are systematically analyzed, and potential directions for improvement in the future are discussed. Several notable conclusions were drawn from this study. First, the typhoon catastrophe index insurance, which is based on the circular catastrophe box and uses typhoon intensity levels as a stratification criterion for the payout structure, offers a straightforward methodology, easy recalculations, readily accessible data, and transparent results. Second, this form of insurance facilitates rapid claim settlements, incurs low operational costs, and effectively mitigates moral hazard. Third, the existing typhoon catastrophe index insurance program may encounter high basis risk and underestimate the severity of typhoon hazards, particularly in the context of climate change and the situation wherein a single typhoon impacts multiple municipalities. Finally, improvements to the current typhoon catastrophe index insurance program in Guangdong could be achieved by more deeply and comprehensively analyzing the spatial and temporal patterns of typhoon events, incorporating additional parameters with clear physical meanings, and refining the probability distributions of typhoon disaster events. The insights outlined in this paper may potentially enhance understanding among scholars and practitioners of typhoon catastrophe index insurance programs and provide guidance for extending catastrophe insurance in other typhoon-prone areas.

China has numerous islands and reefs with complex terrain that are heavily impacted by tropical cyclone disasters. High-resolution tropical cyclone wind-field simulations are beneficial for representing the spatial variations in wind speeds. It is important to conduct high-resolution simulations on relatively small islands and reef areas. To explore the differences in tropical cyclone wind field simulations at various spatial resolutions in the island and reef areas of China, this study compared the modeled wind fields of historical tropical cyclones in China's island and reef areas, which have complex terrains, including plains, peaks, valleys, and cliffs, at three spatial resolutions of 1,000 m, 90 m, and 30 m. The wind fields were modeled using land cover and elevation data of the three spatial resolutions as inputs and validated against observed winds at eight stations. Comparisons were made regarding the differences in wind speeds of tropical cyclones with a 100-year return period at three spatial resolutions. The results showed that: (1) the 30 m resolution achieves the best accuracy, with a root mean square error of 4.28 m/s, lower than those of 90 m and 1 km by 0.08 m/s and 1.04 m/s, respectively. (2) Different spatial resolution simulations showed that wind speed errors were related to terrain types. For example, on Zhujiajian Island, located in Zhoushan City, the 30 m resolution captured the spatial heterogeneity of winds better than the other resolutions, especially for mountainous, valley, and cliff terrains. Comparisons between the simulated wind speeds at 90 m and 1,000 m resolutions versus those at 30 m resolution indicate that the differences in the simulation percentages are as follows: 6.57% and 7.61% for peak terrain, 21.28% and 17.35% for valley terrain, and 22.85% and 23.37% for cliff terrain, respectively. Additionally, the 30 m simulation was more sensitive to transitions between windward and leeward slope terrains. (3) For the 100-year return-period wind speeds, the 30 m resolution produced the highest values and largest spatial variations. On Zhujiajian Island, the maximum wind speeds at 1,000 m, 90 m, and 30 m resolutions were 71.13, 73.18, and 79.97 m/s, respectively, and standard deviations of 3.88, 3.72, and 7.18 m/s. This study demonstrates the importance of using high-resolution data to simulate tropical cyclone winds in complex terrain. However, this study had some limitations. First, the terrain correction factors need to be optimized further. The assessment method provided by the building codes tended to overestimate the impact of the terrain correction factors. In the future, more accurate terrain correction factors could be obtained using computational fluid dynamics and wind tunnel tests. Second, because of the limited types of land cover data used in the calculations, the subdivision of certain land types when calculating the surface roughness is not sufficiently detailed. Additionally, different years of land cover data were not incorporated, making it challenging to reflect the variations in surface roughness. Remote sensing can be used in the future to determine the high-resolution spatial distributions of surface roughness.

The rapid growth of social media has introduced new concepts and technical approaches for disaster management. This paper reviews the characteristics of social media data and its application potential in disaster management research, providing a new research perspective for the field of disaster management. Taking the impact of Typhoon Doksuri in Fujian Province in 2023 as a case study, this research employs Latent Dirichlet Allocation (LDA) topic modeling to analyze the practical application effectiveness of social media data at different stages of disaster management from three perspectives: the spatiotemporal distribution of posts, trend analysis of different types of entities, and evolution of topic content. These findings indicate that the synchronous relationship between the popularity of related topics on Weibo and the impact of a disaster event confirms the effective application of social media data in disaster management. By monitoring the dynamics of information dissemination on social media, we can determine the occurrence status and impact scope of disasters in real time. During disasters, different user types have different foci. Individual users tend to focus more on the restoration of living facilities and the supply of relief materials, whereas organizational users concentrate on disseminating information about disasters and emergency response measures. The information provided by different types of users can provide a more comprehensive and diversified perspective on disaster perceptions for disaster management. Analysis of the evolution of topic content can reflect the evolution of emergency response dynamics and public attention needs in different cities at different stages of disaster management, thereby developing more practical emergency response strategies. Through the mining and analysis of social media data, this study recognizes the entire process of disaster occurrence from the perspective of social media data, thereby enriching the relevant theoretical and empirical research. Future research could be conducted from perspectives such as utilizing other multisource data, integrating machine learning and deep learning technologies to enhance the accuracy of topic information extraction, and exploring the application of social media data to post-disaster emergency rescue and infrastructure support.

Typhoons and their associated disaster chains pose serious threats to the lives and property of coastal residents, and they remain a focal point for research and response. Previous studies on typhoon disaster chains often employed high-dimensional symmetric Copula models to establish the joint distribution of multiple hazard factors, however they failed to explore the complex nonlinear and asymmetric dependencies among them. This study aimed to depict these complex relationships more comprehensively and efficiently to provide a more accurate typhoon hazard assessment. Focusing on Zhoushan, a city comprising numerous islands in Zhejiang Province that faces multiple typhoon threats, this study employed the C-Vine Copula function to model the complex dependencies among "strong wind-rainstorm-storm surge" in the typhoon disaster chain. Utilizing observational data from 1979 to 2018, this study involves three main steps: first, fitting the marginal distribution of each hazard factor and identifying the best one from Lognormal, Gamma, GEV (Generalized Extreme Value), and Burr functions based on the K-S test; second, fitting the bivariate joint distributions of wind speed-rainfall and wind speed-storm surge using Gaussian, Clayton, Gumbel, Frank, and Joe Copula functions, and determining the best fit based on the AIC (Akaike Information Criterion); and finally, estimating the trivariate joint probability distribution and corresponding return periods for wind speed-rainfall-storm surge using the C-Vine Copula function. This revealed (1) a strong correlation between wind speed and rainfall observed within regular value ranges (non-extreme conditions), were best represented by the Frank Copula, In addition, wind speed and storm surge exhibit an upper-tail dependence, best captured by the Gumbel Copula. (2) The rainfall distribution under certain wind speed conditions revealed dual peaks, whereas the storm surge distribution maintained a uniform pattern, with the best joint distribution fitting the Gumbel Copula. (3) Considering a 100-year return period for individual variables, the bivariate return periods for wind speed-rainfall and wind speed-storm surge events were significantly reduced to 29 and 30 years, respectively, while the trivariate return period for the wind speed-rainfall-storm surge combination was further reduced to 17 years. Overall, the C-Vine Copula function effectively characterizes the complex nonlinear and asymmetric dependencies among the typhoon disaster chain "strong wind-rainstorm-storm surge", reducing high-dimensional parameter estimation complexity. This method provides new insights for constructing joint probability and return period models for multiple hazard factors and offers a scientific basis for disaster risk assessment and management strategies. Therefore, this enhances the accuracy of disaster prevention and mitigation efforts. Additionally, the application of the C-Vine Copula assists to deeply understand the mechanisms and development processes of natural disasters, providing new tools for on-site emergency response and decision-making.

China is frequently affected by tropical cyclones, which can lead to severe economic losses. Rapid disaster loss assessment is crucial for effective emergency response. A variety of factors affect tropical cyclone disaster losses, which can be roughly categorized into hazard, exposure, and vulnerability. In the past, traditional statistical methods were used as the main tools for disaster loss assessment. To explore the potential of machine learning models, we explored five algorithms: the Light Gradient Boosting Machine (LightGBM), Random Forest (RF), eXtreme Gradient Boosting (XGBoost), Support Vector Machine (SVM), and Back-Propagation Neural Network (BP). The maximum gust wind and rainfall of tropical cyclones were selected to represent hazards, fixed capital stock data were used for the valuation of exposure, and the GDP of each county was collected to reflect capacity or vulnerability. In addition, river network density data were used as a simple proxy to demonstrate the contribution of flood-induced tropical cyclone rainfall. The relationship between these input variables and disaster loss at the county level was developed based on the data of 81 tropical cyclone events from 2009 to 2020 in Fujian Province. The performance of these models was compared using accuracy, precision, recall, and F1 scores. The accuracies of the LightGBM, RF, XGBoost, SVM, and BP models were 0.794 6, 0.772 6, 0.762 8, 0.251 8, and 0.268 1, respectively. The main findings are as follows: (1) The performance of the ensemble learning algorithms (RF, XGBoost, and LightGBM) was higher than that of the individual classifiers (BP and SVM). The LightGBM model exhibited the best performance, with accuracy, precision, recall, and F1 scores >79%. (2) Maximum hourly rainfall and maximum wind gust are two of the most important loss-inducing factors, and fixed capital stock is a better proxy for disaster exposure than GDP. (3) The modeled losses are consistent with the actual losses under different but typical tropical cyclone events, indicating that the models can be applied to future tropical cyclone events impacting Fujian Province. However, this study had some limitations. First, some natural hazards, such as floods, storm surges, and waves, were not fully considered, which introduced uncertainty into the model results. Second, the emergency response capacity and actual actions taken among counties may have varied dramatically and were neglected due to data unavailability. In the future, hazard and vulnerability variables should be obtained to extend the model inputs. In addition, whether the model parameters trained with data from Fujian Province can be applied to other provinces remains unaddressed. In the future, to develop an operational model for the whole of coastal China, county-level data of all typhoon-prone areas in China with long-term time series are needed.

The "enclave economy" is an important governance tool for promoting regional integration. Guangdong Province occupies the leading position in exploring the "enclave economy" model in China, which has effectively promoted the development of the east and northwest of Guangdong Province through the "point to area" approach. However, certain problems that are associated with the "enclave economy" concept, including a weak level of industrial relatedness, disconnection with the development of the local urban system, and inadequate interest driving mechanisms, need to be urgently addressed. The article aims to explore the high-quality development path of the "enclave economy" in the new era, taking advantage of the symbiosis theory. Based on field research and semi-structured interview methods, the present study attempts to not only probe into the cooperative relationship and mutually beneficial symbiosis mechanism among different actors in the "enclave economy" but also explore a more sustainable and mutually beneficial development "enclave economy" model. With respect to theoretical contribution, based on the symbiosis theory and the characteristics of the "enclave economy", this study facilitates a better understanding of the high-quality development logic of the "enclave economy" from the perspective of symbiosis in particular and establishes a theoretical framework comprising the "industrial symbiosis network-industrial symbiosis unit-interest symbiosis mechanism" components. Empirically, this study takes the Guangqing Economic Cooperation Zone (Guangde Park) as the case study; reveals the development process and problems of the "enclave economy", including the isolation of industry transplantation, fragmentation of industry-city units, and locking of interests and mismatch between rights and responsibilities; and proposes high-quality development strategies, such as establishing a cross-regional "enclave economic circle", a resource-linking platform between industry and city, and a community of interests in industrial parks and towns, to form a more sustainable symmetric and mutually beneficial symbiotic mechanism. The key contribution of this study lies in the theoretical framework for the high-quality development of the "enclave economy" through the lens of symbiosis, which enriches the ways of analysis and cognitive logic of the "enclave economy" and advances cross-regional cooperation and "enclave economy" research. It enhances the cross-territorial geographic thinking of regional cooperation and "enclave economy" research, holding the potential to provide decision-making references for the promotion of regional coordinated development in Guangdong Province in the new period. It also has practical application value for relieving the pressure of unbalanced and insufficient regional development in China by promoting cross-municipal and cross-provincial cooperation.

Mangroves are halophytic forest plant communities located on saline marshes in estuaries of tropical and subtropical bays. They are one of the most vulnerable ecosystems in the world and are severely threatened by urban development, environmental pollution, aquaculture, and other problems. The Dongchong mangrove forest is a relatively well-preserved mangrove forest in China, with a large area and a typical Excoecaria agallocha landscape, which has significant ornamental and ecological conservation value. The aim of this study is to provide basic support not only for mangrove ecological conservation and restoration, but also to construct and manage nature's reserves. The eco-environmental geological characteristics of mangroves were investigated using geology, geomorphology, pedology, ecology, and other methods, and a typical eco-environmental geological profile of the mangrove in Dongchong was drawn. The results show that the strata in the study area are mainly Quaternary sediments and rhyolites of the Nanshancun Formation of the Early Cretaceous. Faults are developed in the west of Dongchong Mangrove Wetland Park. The main environmental geological problems are uneven ground settlement, ground subsidence, and ground cracks. The concentration of F^- in the surface water are high, and the water quality is slightly lower than that of the Class III water standard; however, the groundwater is freshwater with low salinity and hardness. Cd and Tl are locally significant in the surface soil of the study area. N, P, CaCO₃, Org, and B are deficient in the soil, whereas the K content is mainly medium. A part of the soil is polluted by heavy metals, particularly As, followed by Cd. However, the mangrove leaves are rich in nutrients, indicating that the lack of soil nutrient elements and heavy-metal pollution are not the major factors limiting the growth of mangroves in this region. Improving the growth environment of mangroves should include expanding the landscape area and reinforcing reserve management. In the rock-soil-plant ecosystem, As, Pb, Cd, and B are significantly rich in the soil, indicating that their contents have a slight correlation with their parent rocks. Ni, Cu, Zn, and K are limited by the parent rock contents, and some elements including P, Mo, and Cr show enrichment capacity in the soil. The BCF >2 of mangroves of the mangrove forests in Dongchong are P and B, indicating that the mangrove trees have a higher absorption capacity for P and B. In contrast, the BCF values of As, Pb, and Cd are relatively low, which, in addition to the weak absorption capacity of the mangrove trees for these elements and combined with the geochemical characteristics of the soils in the study area, are also affected by the high Cd and As contents of the soil. All the data presented in this paper are from the project, "Ecological and Environmental Geological Survey of Shenzhen Nature Reserves," for which we express our sincere gratitude.

In the context of globalization, cross-boundary regions have become strategic areas for improving national competitiveness and promoting local development. Moreover, cross-boundary governance has gradually become a key issue in regional integration research. Recently, with the increasing trend of anti-globalization, exploring regional governance transformation is crucial for national development. This article conceptualizes a research framework that is a cross-boundary governing network based on policy network theory. It is believed that in cross-boundary governance, various state actors based on common development goals form multi-level and systematic state communities under the restructuring of state capacity while working together to promote cross-boundary regional development. Among them, economic territorialization and state capacity are the key to understanding this concept. Furthermore, under the institutional framework of "one country, two systems," an empirical study was conducted using the Shenzhen Hong Kong cross-boundary region as an example, highlighting the close relationship between the process of economic territorialization and the construction of the cross-boundary governing network. This study explored the operational methods of cross-boundary governing network, and further analyzed the impact of state-society paradigms on the operation of cross-boundary governing network under asymmetric governance. Research has proven that the cross-boundary governing network is a resilient governance mechanism for understanding the process of government-led institutional integration in cross-boundary areas. The new framework also contributes to the policy network as follows: First, the new conceptual framework is more likely to be understood as a complex, multi-type mixed network that is used to overcome the problem of the limited applicability and oversimplification of ideal policy network typologies in practice. It helps to understand the connection between the state-led decision-making process and the state-society interaction process. Second, it is configured on a logical need to contextualize the policy network to the broader and everchanging meso-level territorial scales within which state actors are defined and located within different state-society relations. Third, the factors of "resource" and "power," which are the functional core of the policy network, have yet to be fully defined with little consensus. The "new" will be centered on the configuration and realization of the state capacity of involved state actors as the bridging role of both meso-level networks. Furthermore, the "general-purpose" and "task-specific" components inherent in the multilevel governance approach are adopted to describe different systematic state communities. Meanwhile, the inter-actor idea of an "advocacy coalition" is also incorporated to understand the consensus-forming process within the intra-territorial network. Under the dynamic construction of the cross-boundary governing network, this multi-level and systematic governance approach will continuously deepen the development of Shenzhen Hong Kong cross-boundary cooperation, to make a theoretical contribution to cross-boundary synergistic development in other regions.

This research delved into the complex dynamics of heritage communities during urban renewal, navigating the tension between preserving local heritage and embracing modernization. This study centered on Hangzhou's Mantoushan community and utilized a combination of fieldwork, participatory observation, semi-structured interviews, and online text analysis to investigate the interplay between spatial transformation and the construction of local identity in the context of urban development. This study aimed to dissect the multifaceted effects of urban renewal on the physical and emotional fabric of heritage spaces, with a particular focus on the microhistorical perspective. The methodology involved a comprehensive approach, capturing the voices of residents, tracking changes in spatial usage, and analyzing digital narratives to provide a nuanced understanding of the community's evolution. The results of this study underscore the dual impact of urban renewal. On one hand, it has led to improvements in the built environment and public amenities, fostering a renewed sense of community pride and attachment among residents. On the other hand, the process has been instrumental in the creation of a second space, as envisioned by authoritative bodies, which in turn, has given rise to a third space characterized by commercial, productive, and recreational functions. This transformation has been marked by diverse actors' reconstruction of the third space influenced by their varied perceptions and aspirations, which has led to a sense of dislocation and internal community division. The conclusions drawn from this study highlight the importance of recognizing the uneven and unstable nature of the transition towards a third space. It advocates for a more inclusive approach to urban renewal that acknowledges and addresses the diverse needs and aspirations of community members. This study also emphasizes the critical role of emotional connections and empathy in the sustainable development of heritage communities, cautioning against the illusion of a second space that overlooks the complex realities of community life. This study provides a compelling argument for a more nuanced understanding of the impacts of urban renewal on heritage communities. It calls for a balanced approach that respects the historical significance of these spaces, while embracing the potential for modernization, ensuring that the process of renewal is one that enhances rather than erodes the communities' sense of identity and belonging. The insights gained from this study are not only relevant to the Mantoushan community, but also offer valuable lessons for urban planners and policymakers worldwide, as they grapple with the challenges of integrating heritage conservation with the demands of contemporary urban life.

The prediction of rainstorms and floods in small and medium-sized watersheds, as well as the synthesis of related parameters, plays a pivotal role in preventing flood disasters. Environmental changes have led to an increase in hydrological extremes such as rainstorms and floods, presenting unprecedented challenges for small and medium-sized river basins. In this review, we systematically categorize, and summarize the processes involved in predicting rainstorms and floods in these watersheds, along with advancements in correlated parameter synthesis research. Furthermore, we analyze and discuss the most commonly employed runoff and confluence estimation methods and their associated parameters in practical applications, as well as their limitations. First, we establish the concept of small- and medium-sized watersheds across various academic disciplines. From a hydrological perspective, these watersheds typically exhibit slope confluence and have relatively small catchment areas. In terms of eco-hydrology, the ecological water demand of the basin must be calculated based on the different communities occupying the river basin and divided by area according to the ecological samples from each district after the investigation. Thereafter, we summarized the methods and types of runoff calculation and parameter synthesis in small- and medium-sized basins, and the methods and principles of runoff analysis, such as rainfall–runoff correlation diagram, infiltration curve method, deduction method, runoff coefficient method, and hydrological model method as well as the methods of parameter synthesis, such as rainfall-runoff correlation diagrams and loss methods are introduced. Second, we summarize and discuss the assessment of confluence and its associated parameters in small- and medium-sized river basins. This encompasses background information and various calculation methods, such as the instantaneous unit line, comprehensive unit line, inference formula method, and empirical formula method. We also examine how the three major elements of parameter synthesis convergence influence confluence parameters. We emphasize that combining radar rainfall measurements, high-resolution remote sensing, high-performance computing, and deep learning can facilitate research on simulating and forecasting rainstorms and flood processes in small- and medium-sized basins. However, a significant portion of these basins lacks data, limiting the application of simulation and flood forecasting. To address this, integration with geographical parameters specific to small- and medium-sized basins is necessary to enhance regional reliability and forecasting accuracy. Additionally, when applying deep learning to simulate basins with limited or no data, the significance of parameter synthesis becomes even more pronounced. Finally, we discuss the problems and challenges associated with storm flood calculations and parameter synthesis methods in small- and medium-sized basins and offer predictions regarding future research and technical developments. We recommend strengthening the use of emerging technologies for watershed runoff and runoff parameter calculations and advocate for their application in storm flood design.

In response to global climate change, China has incorporated carbon peaking and carbon neutrality into its overall economic and social development. National-level new areas are critical strategic carriers for high-quality regional economic development in China, playing an essential role in promoting carbon reduction. Objectively evaluating the carbon-emission-reduction effect of national-level new areas can help accumulate and promote China's low-carbon construction experience, and thus, comprehensively facilitate greening and ecological civilization construction. In this study, the impact of the establishment of national-level new areas on carbon emissions in their respective cities were investigated using the difference-in-difference method. The findings show that: 1) the establishment of a national-level new area can significantly minimize the carbon emissions in the city in which it is located, and after three years of establishment, it will have a significant long-term inhibitory effect on the carbon emissions of the city. This conclusion is still valid after a series of robustness tests, such as propensity score matching + difference-in-difference; 2) The national-level new area policy mainly reduces carbon emissions in a city through technological and energy-saving effects but cannot yet reduce them by adjusting the industrial structure. 3) The impact of the establishment of national-level new areas on the carbon emissions of surrounding cities shows an "∽" trend of increasing first, then decreasing, and subsequently increasing. It has a significant carbon-reduction effect on cities within the range of 200-250 km, indicating that national-level new areas can help promote carbon-emission reduction in surrounding cities. 4) The national-level new area policy has a higher carbon-emission-reduction effect on northern cities than on southern cities. The single-city layout model of the national-level new area has a significant carbon-emission-reduction effect on the host city, whereas the dual-city layout model does not significantly reduce the carbon emissions in the host city. This study investigated the carbon-emission-reduction effect of national-level new area policies and examined carbon-emission reduction in the national-level new areas of pilot cities through technological and energy-saving effects. This study helps to improve the theoretical understanding of national-level new area policies and carbon-emission impact mechanisms and provides a policy reference for China's promotion of the "dual-carbon" strategy.

The autonomy and travel conditions for older adult tourists have significantly improved, leading to a diversification of their tourism activities. Among these, the concept of a free and comfortable sojourn has gained popularity. Despite the complex concept of older adult sojourns being established in related research, the concepts often overlap and are fragmented, leading to a disjointed understanding of the phenomenon. This study aims to incorporate the life-span theory of control and its optimization strategy framework from a life-span development perspective in older adults. By deeply connecting research on older adults with tourism research through life-span development thinking, we aim to explore methods of coordinating and analyzing older adult sojourns. This approach will allow us to systematically reshape existing conceptual knowledge. Based on the results of this coordinated analysis, we aim to gain a systematic understanding of older adult sojourns and propose future research directions. The study revealed that older adult tourism exhibits strategic traits consistent with the life-span theory of control, where resource allocation and willpower investment are crucial elements. This forms a resource-willpower investment framework that categorizes 16 different older adult tourism behavior patterns. Using this framework, by comparing the characteristics of older adult travel with the 16 classification results, the resource and willpower investment framework is focused on the amount of resources invested in the destination and the distance of the trip. This further refines the corresponding older adult travel patterns into four types: relatively high investment in travel to distant areas, relatively high investment in travel to nearby areas, relatively low investment in travel to distant areas, and relatively low investment in travel to nearby areas. The study reveals that the four categories represent varying lifestyle demands and participation limitations for older adults. Those who invest more and travel longer distances tend to face greater participation challenges, have fewer companions, require more from their destinations, and have limited choices. Conversely, those who invest less and travel shorter distances experience the opposite. The four categories of older adult travel display different scene transitions and state changes, each with unique participation challenges, social choices, and destination requirements. Overall, the categorization of older adult tourism types and the comprehensive analysis of older adult travel types constitute a process of knowledge creation. The research employs deductive methods for progressive exploration, building a comprehensive classification framework. This framework lays a cognitive foundation for future research and provides key directions. The innovative research approach, in conjunction with the life-span theory of control, provides a method for pattern analysis to understand ongoing tourism behaviors and phenomena that are constantly evolving and enriching. Older adult sojourn is one of the few forms of tourism that is notably age-friendly. The prospects for research and industrial development of this phenomenon are promising, but there is currently a lack of discussion about the phenomenon itself. Future research can build upon this initial understanding to further investigate behavioral characteristics, values related to aging, and local response needs. By examining behavior, subject, and space, a study can be conducted on behavior, motivation, space, and their interactive results, leading to more systematic findings and enhancing the practical value of the guidance.

Cultivated land is the cornerstone of grain production and the basic resource to ensure food security. Understanding the non-grain production status of cultivated land in the main grain-producing areas of western China is necessary to provide a basis for regional sustainable agricultural development and cultivated land protection decision-making. In this study, Chengdu Plain was selected as an empirical research area. A mathematical quantization model and spatial autocorrelation method were used to analyze the spatiotemporal characteristics of non-grain production of cultivated land in Chengdu Plain, and an econometric model was constructed to identify its driving factors. The results showed that the cultivated land area did not change significantly in the Chengdu Plain from 2000 to 2019; however, the small change in cultivated land area did not mean that its actual use changed little, and the non-grain production status of cultivated land was obvious. (1) From 2000 to 2019, both the Non-Grain production Area (NGA) and the Non-Grain production Rate (NGR) in Chengdu Plain showed a fluctuating and increasing trend, with an increased rate of 4.40% and 13.53%, respectively, which indicates that cultivated land protection and food security were under great pressure. (2) In terms of space, the NGA in 34 districts and counties of Chengdu Plain presents a multi-center scattered distribution, which shows a spatial pattern of high in the center and low in the northeast and southwest, and the NGA's spatial agglomeration areas are concentrated in Chengdu and its neighboring cities. (3) Economic Crop Planting Scale (ECPS), Agricultural Structure Adjustment (ASA), Urbanization Rate (UR), and Cultivated Land Protection Policy (CLPP) are the most important factors affecting the non-grain transformation of cultivated land in Chengdu Plain. Some suggestions are proposed: red lines should be drawn to implement a control system for cultivated land use; departmental collaboration must be strengthened to build a synergy of cultivated land protection; the agricultural subsidy system must be improved to defend farmers' fundamental rights and interests; and policy advocacy for cultivated land protection should be enhanced to raise food security awareness. This study can better reflect the non-grain production status of cultivated land in Chengdu Plain, and from the spatial unit of district and county, it provides a good perspective for the study of the non-grain production of cultivated land. This study also provides a scientific foundation for decision-making regarding regional sustainable agricultural development and cultivated land protection.

Quantitative studies of mangrove leaf functional traits will help us understand the adaptive evolutionary strategies of mangrove plants and the relationship between mangrove biodiversity and ecosystem functions. Because of the special environment of the intertidal zone where mangroves are located, it is very difficult to obtain the functional traits of mangrove canopies from the ground, and relevant studies are lacking. The maturity of Unmanned Aerial Vehicle (UAV) hyperspectral remote sensing technology provides a new means of conducting such research. This study considered mangroves on Qi'ao Island, Zhuhai, as the research object. Based on UAV hyperspectral data, two UAV hyperspectral data processing methods, which combined Partial Least Squares Regression with Normalized Difference Vegetation Index (PLSR+NDVI) and Partial Least Squares Regression with Continuous Wavelet Transform (PLSR+CWT), were used to estimate the 10 canopy leaf functional traits of mangroves on Qi'ao Island. The results showed that the PLSR + NDVI method was more suitable for the inversion of mangrove canopy-specific leaf weight (LMA), phosphorus content per unit mass (P_mass), and nitrogen content per unit area (N_area), whereas the PLSR + CWT method was more suitable for the estimation of the nitrogen/phosphorus ratio (N/P), chlorophyll content (C_ab), and carotenoid content (C_xc). However, the results of the above two methods for retrieving the nitrogen content per unit mass (N_mass), potassium content per unit mass (K_mass), phosphorus content per unit area (P_area),and potassium content per unit area (K_area) were not ideal (R²<0.3). The optimal method established in this study was used to estimate the contents of LMA, P_mass, N_area, N/P, C_ab, and C_xc of the mangrove canopy leaves in the study area and map their spatial distribution. Mangrove canopy leaf functional traits obtained using UAV hyperspectral data inversion better reflect the horizontal structure and function of the mangrove community. Regarding the spatial distribution patterns of canopy leaf functional traits, the spatial distribution patterns of N_area, C_ab, C_xc, and N/Pwere relatively consistent with higher values in the middle region and lower values in the edge region. The spatial distribution patterns of the LMA and P_mass were similar, and the distribution was relatively uniform throughout the study area. Combined with ground survey data, the internal relationship between species composition and spatial patterns of functional traits, as well as ecosystem functions and processes, can be deeply explored, and rapid investigation and assessment of mangrove forests can be realized at the community and ecosystem scales. The spatial distribution pattern of functional traits was closely related to the spatial distribution pattern of canopy structure and species. The inversion model of hyperspectral functional traits was constructed by separating mangrove species with different life types, which is expected to further improve the inversion accuracy of the model. Constructing a specific functional trait inversion model for each mangrove species, combined with the species identification results of visible-light images, will effectively improve the inversion accuracy of mangrove canopy leaf functional traits.

China has entered a critical period of economic transformation and rapid development. In this context, it is important to promote the coordinated emission reduction of carbon dioxide and environmental pollutants, transformation of the economic growth model, realization of the "double carbon" goal, and high-quality economic development. Within the framework of the synergy of pollution and carbon reduction, we constructed a comprehensive evaluation index system and used the improved TOPSIS model to measure the synergy index of pollution and carbon reduction in urban agglomerations within the period from from 2010 to 2019. Combined with spatial autocorrelation analysis, a composite system synergy model, and a regression model, the spatial and temporal evolution laws and collaborative development level of the synergy of pollution and carbon reduction in urban agglomerations were analyzed, and the factors influencing the synergy between pollution and carbon reduction were explored. Following conclusions were drawn from the results. (1) From 2010 to 2019, the synergistic effect of pollution and carbon reduction in three major urban agglomerations showed a steady growth trend, with different spatial distribution patterns. The synergistic index of pollution and carbon reduction in the Yangtze River Delta urban agglomeration shows an overall upward trend, that in the Beijing-Tianjin-Hebei urban agglomeration shows a steady fluctuation, and that in the Pearl River Delta urban agglomeration shows a slow growth trend. (2) The spatial correlation characteristics of the Beijing-Tianjin-Hebei urban agglomeration change from random to regular distributions, and the synergistic cooperation mechanism of pollution and carbon reduction among cities in the Yangtze River Delta urban agglomeration needs to be strengthened. The radiation and driving effect of the cities in the Pearl River Delta urban agglomeration on the surrounding cities is gradually increasing, and the local spatial agglomeration of these three major urban agglomerations is not evident. (3) From 2010 to 2019, the order degree of the synergistic system of pollution and carbon reduction showed a significant growth trend; the overall synergy degree of the composite system is low, and the growth order of the urban agglomerations is as follows: Yangtze River Delta > Beijing-Tianjin-Hebei > Pearl River Delta. Different evolution and correlation characteristics are observed in space, and no internal coordination of urban agglomerations is seen. (4) Economic development, environmental pollution, environmental governance, ecological protection, and resource utilization are important factors affecting the synergistic evolution of pollution and carbon reduction in the three aforementioned major urban agglomerations. This study analyzed the connotation requirements and specific characteristics of the synergy between pollution and carbon reduction in such agglomerations in the coastal areas of China. Based on the analysis of the spatial and temporal evolution and influencing factors of the synergy of pollution and carbon reduction in these agglomerations, we aim to address the problems existing in the synergy of pollution and carbon reduction in urban agglomerations. Corresponding countermeasures and suggestions are put forward to provide an empirical reference for the realization of comprehensive green and low-carbon transformation and high-quality green development of urban economies and societies.

The study of everyday life has gained attention across various disciplines in the context of modernity. This study utilizes Lefebvre's rhythmanalysis to explore the everyday experiences of residents in the Xiguan Community, a historically significant residential area in western Guangzhou undergoing urbanization and tourism development. Adopting an emic perspective, this study employed auto-ethnography to depict the daily rhythms and spatially embodied experiences of the author, a native resident of the Xiguan Community. By incorporating reflective and self-narrative elements and comparing them across generations, this approach provides first-hand knowledge and self-awareness. This research offers an insider's comprehensive understanding of the effects of urbanization and tourism on residents' everyday lives. Informed by Lefebvre's rhythmanalysis, this analysis incorporates spatial and temporal dimensions, with a specific emphasis on residents' experiences of spatial embodiment and their engagement with everyday rhythms. The study reveals two key findings: First, urbanization and the commodification of landscapes have created a constructed "the present" in traditional communities, displacing the meaningful "existence" of everyday life. Certain spaces within these communities have detached from residents' everyday lives, serving urban and tourism purposes, and leading to partial alienation in spatial and temporal dimensions. These spaces represent the simulacra and fragments of residents' everyday lives, lacking subjectivity, temporality, and wholeness. Over time, the "existence" that embodies the meaning of residents' everyday lives has been squeezed out by structural forces such as urban renewal and community tourism. For tourists, these landscapes may serve only as replicas of attractions, devoid of the essence of residents' everyday lives. For the residents, these community spaces have become manifestations of instrumental rationality and commodification. Second, this study highlights that traditional community residents' bodies are disciplined and governed by the instrumental rationality of urban production and the invisible rhythms of the tourism industry. In large cities, the significance of individual bodies in traditional urban communities is often overlooked, as bodies become tools for creating value through work. Individuals adjust their everyday rhythms based on urban settings' production rationality and efficiency priorities. This undermines the bodily rhythms that align with natural cycles and prompts residents to distance themselves from traditional communities. While the older generation in the Xiguan Community experiences overlapping leisure time and shares community spaces, fostering solid social relationships, the younger generation faces longer working hours, extended commuting distances, and more individualized leisure time. As a result, there is a lack of synchronization in leisure rhythms among neighbors. The embodied rhythms of traditional community residents have shifted from a state of harmony with natural rhythms and community spaces to being governed by the instrumental rationality of urban production and invisible rhythms of the tourism industry. This study provides an emic and longitudinal perspective to the investigation of spatial experiences and embodied rhythms in urban and tourism development. The use of auto-ethnography amplifies residents' voices and calls for greater consideration of local daily life. These findings emphasize the importance of incorporating residents' everyday experiences into the planning and development of sustainable communities and tourism.

A short overview of the history of academic geography since the 19th century shows that there has never been a unity of physical and human geography in the past, at least in the form that is strived for today to justify the relevance of geography in coping with the present problems faced by humanity. But the fact that the limits of positivism start to be recognized in physical geography opens a way to collaboration for addressing the pressing problems affecting our planet today. The paper ends with some examples of how such a collaboration might look like and advocates greater attention to a political chorological approach, concentrating on the diversity of regions in the world, by taking both their internal and external relationships in terms of power structures into account.

High-quality air service is important for achieving high-quality aviation development. As the primary customers of air travel services, passengers are the most important evaluators of the service. Therefore, research on their air travel choices is key for promoting the coordination of multi-airport regions. Based on stochastic utility psychological perception theories, this study discusses the impact of the key dimension of airport service quality on air travel choices using the structural equation model-logit model. The results show that air travel choice is not a simple linear extension of behavioral intentions as there are two key dimensions of airport service quality: First, mandatory service processing is inevitably the most time-consuming and tedious process for passengers at airports. This waiting time is perceived as a sign of low airport service capability, whereas the level and quality of service provided by staff in this process is an intangible factor for passengers. This in turn affects the level of passengers' ratings of airport services, especially for business travelers. Therefore, airports need to recognize the time and resource constraints of passengers and work with airlines to streamline the check-in process, ensure security control, and reduce waiting time. One solution is to use shared self-service devices or automated robots that allow any passenger of any airline or flight to check-in and check-out on the same device. Second, while facilities, equipment, and environment are not universal considerations for passengers, differences in passenger perceptions are evident between airport types. Within multi-airport regions, the facilities, equipment, and environment of major airports are above passengers' psychological expectations, while auxiliary or other airports need to pay more attention to this service, which illustrates that the improvement of airport service quality requires changes to unidimensional and monolithic thinking but also focus on passengers' overall perception of service experience from a multidimensional perspective, as well as consideration of the spatial and temporal characteristics of different airport types in the multi-airport region to make targeted improvements. Moreover, passengers do not have an obvious preference for particular airlines, but low-cost airlines still hold a certain appeal for passengers when they take off from regional airports, which also means that low-cost airlines ' entry into the market has anti-risk properties for regional airports. Within the limits of China's aviation controls, the presence of low-cost carriers can still improve the chances of an airport being chosen. Therefore, different airport types within the same multi-airport region often need to compete differently to achieve regional synergistic development. To enhance airport service quality, it is essential to fine tune service quality standards, based on airport's types. The improvement of airports' performance should include a phased integration of assessments of service experience settings. Airports should adopt differentiated spatial designs for their service functions based on the goal of airport integration, with a view to achieving optimal management at minimal cost while being able to effectively guide passengers in their air travel choices.

Mangroves are typical ecosystems located in the intertidal zone of tropical and subtropical coasts that protect the area against wave action, promote accretion in river estuaries, and act as an important global carbon sink. However, several natural mangroves have recently degraded due to climate change and human activities, increasing the risk to coastal areas' ecological environments. The mangroves on Qi'ao Island in Zhuhai, China, have been destroyed by human activities and the invasion of the exotic species Spartina alterniflora. In 1999, the Zhuhai municipal government imported pioneer species, such as Sonneratia apetala, to Qi'ao Island to restore the degraded mangroves, which have now evolved into a sufficiently continuous community with a stable area since 2015 with S. apetala as the dominant species. However, because the intensity and frequency of typhoon landfalls are increasing under global warming, dominant species in the mangroves of Qi'ao Island, S. apetala, is more vulnerable to typhoon disturbance due to its height and low trunk density, leading to greater uncertainty regarding their ecological functions on Qi'ao Island. Existing studies have mainly focused on the damage and recovery patterns of mangroves by a single typhoon, having seldom analyzed the response process of mangroves to consecutive disturbances by multiple typhoons; thus, these studies cannot be used to predict the succession process of mangroves with increasing typhoon frequency. In this study, the damage and recovery patterns of mangroves on Qi'ao Island were studied under the disturbance of three consecutive typhoons (2016 NIDA, 2017 Hugo, and 2018 Mangkhut), and their influencing factors were discussed based on the Normalized Difference Vegetation Index (NDVI) using Sentinel-2 remote sensing images. The results showed that (1) the NDVI of mangroves on Qi'ao Island decreased after the typhoon, and the damage levels could be classified as mild or mild to moderate. Moreover, the severity of the damage was relatively small. (2) An annual legacy effect existed across multiple typhoons. The recovery process of mangroves generally followed a circulating succession mode after typhoon disturbances in the order of more severe damage→slow recovery→milder damage→rapid recovery→ more severe damage pattern. (3) The damage levels of mangroves on Qi'ao Island increased with typhoon intensity. However, they decreased if S. apetala recovered slowly before the typhoon. Thus, the recovery pattern was mainly influenced by the damage levels of S. apetala after the typhoon landing and was not largely dependent on the hydrothermal conditions at regional scales. The results suggest that mangroves on Qi'ao Island, mainly consisting of S. apetala,have evolved to adapt to the consecutivetyphoon disturbances, which has promoted their succession from plantations to near natural forests and the formation of a stable typhoon-resistant ecosystem.

Based on the National Census data of 2000, 2010, and 2020, with districts and counties as spatial units, the current situation of population aging is described using a time-series comparison method, and its distribution position is identified using a standard deviation ellipse. Moran's I index was used to investigate the spatial correlation and evolution characteristics of population aging, and the Dagum Gini coefficient and decomposition were used to evaluate its regional differences and sources. Then, a spatial econometric regression model was used to test the factors influencing the spatial differentiation of population aging. This study revealed that the population aging of counties in the Chengdu-Chongqing economic circle has been accelerating as a unit from 2000 to 2020. However, different regions before and after 2010 have shown relatively different changes. The center of population aging in the counties gradually shifted to Chengdu over time. Population aging in counties of the Chengdu-Chongqing economic circle mainly shows the spatial distribution characteristics of similar types of agglomeration; counties with significant spatial correlation are mainly characterized by high-high or low-low type clustering, of which the latter has gradually concentrated in Chengdu and Chongqing during the survey period. After 2010, the high-high type clustering areas rapidly concentrated on the two wings of the central axis of Chengdu and Chongqing. The overall difference in population aging of the counties in the Chengdu-Chongqing economic circle accelerated during the investigation period. The increase and decrease in intra-regional differences varied among different periods, with increased inter-regional differences occurring after 2010. Hypervariable density contributed the most to the overall difference in population aging. Compared with 2010, factors such as aging inertia, fertility inertia, population inflow, and education level had a greater impact on the spatial differentiation of population aging in the Chengdu-Chongqing economic circle in 2020, and an increasing number of elderly people have been observed to gather in more densely populated districts and counties since 2010. Overall, this study provides a detailed presentation of the spatial imbalance and dynamic evolution characteristics of population aging at the county level in the Chengdu-Chongqing economic circle over the past two decades and reports that, compared to 2000-2010, the population aging in the counties of the Chengdu-Chongqing economic circle during 2010-2020 underwent rapid deepening with an overall increase in differences and showed new changes in deepening speed, regional relative aging degree, and distribution of similar types of agglomeration counties, that could be considered, there are also certain differences in the causes of population aging in the counties.

Memory is an essential structure of the tourism experience. Tourism memory construction is not only an individual's review and sublimation of on-site experience, but also the pursuit and introspection of self-meaning. Although tourism memory is unique and critical, it has not yet been fully examined in local tourism studies, resulting in the focus on on-site experience while ignoring the special role of tourism memory in shaping the landscape and constructing individual self-cognition. In this study, based on theories of autobiographical memory and self-expansion, the Grounded Theory and Structural Equation Model were adopted to investigate the influence mechanism of tourism memory construction on tourists' self-concept expansion based on excavating the dimensions of tourism memory construction. The results showed that: 1) Tourism memory is an unforgettable autobiographical memory formed by individual screening and construction after tourists' on-site experience. Its construction dimensions comprise three basic structures: cognitive appraisal, interactive perception, and affective involvement. Specifically, cognitive appraisal refers to the cognitive feelings generated by tourists based on the objective environment of destinations in their memory. Interactive perception is the participatory perception of the interaction between the host and guest and the interaction between tourists. Affective involvement reflects the emotional properties of memory, which is the corresponding emotional reaction of tourists based on cognitive appraisal and interactive perception. These three elements are interrelated and jointly shape and interpret the landscape constructing tourist' self-identity. 2) Cognitive appraisal, interactive perception, and positive affective involvement in tourism memory help promote tourism-sharing behavior, which significantly and positively influences the individual and social self-expansion of tourists. This finding confirms that cognitive and interactive memories contribute to tourism-sharing behavior. In particular, positive and negative affective involvements are remembered by tourists, but many tourists are more willing to share "positive energy" and express the positive side of tourism memories. In addition, through self-narration and self-expression, tourism sharing deepens reflection of the overall self-perception. 3) Among the direct effects of tourism memory construction on self-concept expansion, cognitive appraisal and interactive perception significantly and positively affect individual and social self-expansion, whereas positive affective involvement only positively affects individual self-expansion and indirectly affects social self-expansion by tourism sharing. Furthermore, this paper theoretically clarifies the dimensions of tourism memory construction, complements the theoretical deficiencies of post-travel memory in previous tourism experience studies, and reveals the subjective significance of tourism memory to self. This paper also introduces the concept of self-expansion in tourism research and complements self-expansion studies in nonrelational contexts. Finally, this study is a practical reference for memory marketing in destinations.

The construction of specialty towns is positioned as an important breakthrough and down-to-the-ground path in the implementation of China's new-type urbanization strategy. It highlights the roles of place-based industrial specialization and agglomeration economics. In this process, the Chinese government plays a supportive and guiding role in enabling and aligning multiple actors to engage with to build new platforms for innovation and entrepreneurial activities that integrate the functions of production, living, and ecology. The specialty towns construction strategy is aimed at promoting people-based urbanization and the regional ability of endogenous development. Given the "top-down" and standardization-led nature of the specialty towns policy program, implementation and practices at the local level are both challenging and problematic. This paper adopts perspectives and concepts from evolutionary economic geography and agglomeration economics to explore the antecedents and mechanisms of urbanization. It emphasizes the geographical spatiality of the program in local implementation. Taking 134 provincial specialty towns of Zhejiang province as research cases, the paper refers to a mixed set of methodologies of on-site, interview-based fieldwork; an online survey; and a document analysis to identify the historical foundations, industry attributes, and development objectives of the specialty towns. It also generates a typology of the 134 specialty towns, as well as a typological guideline regarding policy intervention for the broader implementation of specialty towns in China. Three main types of specialty towns are identified in our study: The first type is built on the basis of state-led, sci-tech industrial parks/new towns, whose development aims are oriented toward the development of new industrial paths. The second type is based on firm-led specialized markets located in small administrative towns that support the upgrading and renewal of existing local traditional industries. The third type is featured by the local presence of place-specific natural or sociocultural resources, and it is based on scenic spots. It is oriented to the development of the tourism economy. In conclusion, this study promotes the incorporation of evolutionary economic geography perspectives into the policy implementation of specialty towns and calls for taking the concepts of history, space, and place into account for a better understanding of these towns. By so doing, future policy methods will not be standardized, quota-based, and top-down.

In China, the equal accessibility of social infrastructure, especially public housing and healthcare, has become a prominent concern in solving the problems of rapid but uneven growth-oriented urbanization in the post-reform era. However, few studies have focused on the accessibility of various healthcare resources to different types of public housing using different transport modes. Utilizing Internet map services, this study first calculated the travel time from talent, economically affordable, and public rental housing to hospitals using three transport modes—walking, public transport, and driving—in Shenzhen, China. Subsequently, the optimized two-step floating catchment area method (2SFCA) was employed to comprehensively evaluate the accessibility of healthcare resources to public housing and explore differences in healthcare accessibility among different populations. The results reveal that: (1) Public housing is located far away from healthcare resources, with 15% of public housing unable to access AAA hospitals within 30 minutes by car, and only 10% able to access ordinary hospitals within 15 minutes. (2) Accessibility of healthcare resources to public housing exhibits spatial heterogeneity, gradually declining from special to non-special economic zones. (3) Talent housing experiences the best accessibility, followed by affordable and public rental housing. (4) Public transportation and walking exhibit greater spatial variation in accessibility than driving. Theoretically, the current public housing accessibility in Shenzhen reflects the common problems of public housing accessibility throughout the country. In the process of promoting the equal accessibility of basic public services, focus on its accessibility should be emphasized. This study proposes an optimized 2SFCA by introducing a Gaussian distance decay function, establishing a multilevel search radius, considering supply and demand-side competition effects, and using real-time traffic big data. Our methodological framework simultaneously considers differences among various types of public housing, hospitals with different service capacities, and diverse travel modes. This provides a new research perspective for a comprehensive and thorough understanding of the equal accessibility of basic public services.

Urban waterfront space has important practical significance for inheriting and developing urban cultural characteristics, promoting the driving role of culture in urban development, and creating regional cultural artistic conceptions. This study comprehensively uses the methods of bibliometric visual knowledge map analysis and a qualitative reading of literature, systematically combing through the relevant research literature with the help of quantitative analysis and a qualitative perception of the literature analysis system. Through this approach, this study summarizes the stage characteristics, theoretical basis, and implications of waterfront space research from the perspective of historical inheritance. The research methods, research content, and hotspots clarified the research context of waterfront space from the perspective of historical inheritance. Based on bibliometric analysis, it is evident that research on the historical inheritance to waterfront space is primarily driven by universities and spans disciplines such as human habitat science, ecology, geography, urban planning, and architecture. Human settlement environment theory, cultural space theory, and place narrative theory together constitute the theoretical framework of the research on the historical inheritance of waterfront space. Domestic research on the historical inheritance to waterfront space in China primarily relies on traditional qualitative methods, while quantitative empirical methods have yet to become mainstream. In general, the research concerning the historical inheritance of waterfront space can be divided into three stages: first, a phase focused on the development and construction of waterfront spaces oriented towards recreation, commerce, and tourism functions; second, a stage of transforming and renewing waterfront spaces by leveraging urban development processes; and third, a stage aimed at preserving the unique cultural heritage of cities through the historical continuity of waterfront spaces. The transformation and revival of waterfront industrial heritage, the renewal and protection of waterfront historic blocks, and the protection and utilization of historical waterfront public space culture have become hot topics in the current research on the historical inheritance of waterfront space in China. This study concludes that the existing research is faced with problems such as unbalanced research areas, insufficient empirical research, and a serious separation of "pleasure" and the "ideal". Future research should focus on the system of waterfront space research as it deeply enriches the research methods, improves the research system, and provides direction and support for the historical inheritance and protection of research of China's waterfront space.

The acceleration of high-quality development in the revolutionary old areas has played a pivotal role in advancing coordinated regional development in China. The 20^th National Congress of the Chinese Communist Party proposed a development strategy for implementing regionally coordinated development, building a new development pattern, promoting high-quality development, and accelerating the rejuvenation and development of special areas such as the revolutionary old regions. However, there is an overemphasis on economic development metrics, a disregard for local practices and characteristics, and a blending of processes and outcomes associated with the high-quality regional development evaluation indicators. To solve these issues, it is essential to establish a set of tailored indicators to evaluate and guide the high-quality and differentiated development of counties in the old revolutionary base areas. Harnessing the essence of high-quality development concept, this study proposes a logical framework for constructing an evaluation index system for high-quality development in counties within the revolutionary old areas. Using the old revolutionary base areas in Southern Jiangxi and Western Fujian as the study areas, a three-level coding process based on grounded theory was employed. This rigorous approach enabled the scientific construction of an evaluation index system for high-quality development in the revolutionary old areas. This index system comprises seven dimensions, namely, innovation-driven, economic development, urban-rural coordination, people's well-being, ecological civilization, internal and external openness, and red culture, encompassing 40 indicators. Furthermore, a critical understanding of high-quality development in the revolutionary old areas, emphasizing the need to inherit, preserve, and promote red culture as a contemporary task guided by new developmental concepts, was gained. The aim was to facilitate enhancing both the scale and structure of economic development. This indicator system uses the entropy method to ascertain the indicator weights and subsequently performs a comprehensive evaluation of the study areas. The findings indicate that innovation-driven factors play a significant role in driving the differences in the high-quality development of the revolutionary old areas. In contrast, ecological civilization is yet to exhibit sufficient potential as a driving force for high-quality development at the current stage. Notably, significant disparities exist in the level of high-quality development between the demonstration areas of Ganzhou and the old revolutionary base areas of western Fujian. These disparities are most evident in the spatial core-edge structure. Additionally, counties at the provincial boundaries demonstrate relatively low levels of high-quality development, warranting increased attention to future high-quality revitalization and development efforts. In comparison to previous research, this study contributes in three key ways. First, an evaluation index system has been constructed using a combined top-down and bottom-up approach, incorporating indicators that account for local practices and characteristics, offering a novel perspective for establishing a high-quality development index system. Second, the national strategic positioning of county-level research units in urban-rural integration development, rural revitalization, and urbanization is highlighted, with county towns identified as pivotal carriers. Urban-rural coordination was identified to be the focus of coordination at the county level. Finally, by extending the core connotations of high-quality development, this study enriches the existing understanding of high-quality development. The research findings hold significant implications for expediting the revitalization and development of revolutionary old areas and for the systematic implementation of high-quality development concepts.

Small and medium-sized mountain rivers have characteristics of short processes, rapid flow rates, and quick responses to extreme weather, thereby playing an important role in the global marine geochemical cycle. Understanding the changes in water and sediment characteristics of small and medium-sized rivers in response to extreme weather can provide scientific support for disaster prevention and mitigation and channel management of river basins. This study analyzed data from the past 60 years to understand the variations in the characteristics of water and sediment in the Qinjiang River of the Beibu Gulf under extreme weather conditions by estimating their variation coefficients and contribution rates. The results of the analyses show the following: (1) The Qinjiang River has an average discharge of 32 and 290 m³/s in normal and tropical cyclone weather conditions, respectively. During a tropical cyclone year, the average flow rate is 9.06 times that during normal weather. The average sediment transport rates during normal weather and tropical cyclones are 0.05 × 10⁴ and 1.15 × 10⁴ t, respectively, wherein the latter is 23 times higher. (2) The average flow rates during normal weather and flood periods are 375 and 2,725 m³/s, respectively; the latter is 7.27 times higher. The average sediment transport rates in normal weather and flood period are 0.07 × 10⁴ and 1.14 × 10⁴ t, respectively, wherein the latter is 16.28 times higher. (3) The average annual contribution rates of tropical cyclones and floods to the runoff and sediment discharge of the Qinjiang River are 10.75% and 20.95% and 16.75% and 30.07%, respectively. Extreme weather contributes significantly to the variations in the water and sediment characteristics of the Qinjiang River. During extreme weather, the Qinjiang River exhibits a surge of water and sediment with inter-annual variations. The peaks of runoff and sediment transport during the transit of tropical cyclones tend to decrease gradually over the years, probably because of the reduction in the impact of their activities. The Qinjiang River is located in the South China Sea. The under construction western land-sea new passage grand project, namely the Pinglu Canal, will provide access to the Beibu Gulf along the Qinjiang River. The results of this study will provide scientific support for the disaster prevention and mitigation of the Pinglu Canal and the construction of the port.

With the rapid development, shared bicycles have gradually become an important part of slow urban traffic in China and have played an important role in satisfying the travel needs and facilitating the transfer of residents. Exploring the spatial and temporal characteristics of the impact of the built environment on shared bike travel is of practical importance to reshape the construction of low-carbon transportation and an urban-friendly cycling environment dominated by slow traffic and public transportation. We analyzed the spatio-temporal characteristics of shared bicycle travel through multi-source big data including Shenzhen's shared bicycle OD data, OSM road network data, Baidu Street View, and POIs and used a multi-scale geographical weighted regression model (MGWR) based on the "5D" index of the built environment to analyze the spatial difference characteristics of the impact of different built environment on shared bicycle flow. The findings of the research indicate that: (1) In terms of time, the shared bicycle flow in the morning and evening peaks of both working and rest days is more significant than that of other periods, and the peak period of the remaining days lags behind that of the working days. (2) In terms of space, the spatial distribution characteristics of the traffic flow of shared bicycles during each peak period exhibit a spatial pattern of "multiple aggregation cores and several extended belts." (3) Significant differences were observed in the impact of various built environmental factors on the flow of shared bicycle travel, among which, employment facility density, enclosure degree and population density had a positive effect in each period; their influences were globally significant; and the remaining factors demonstrated varied characteristics in each period. (4) Factors with significant influence showed different spatial scales in different periods. The spatial changes of employment facility density and enclosure in each period were generally flat; the spatial changes of proximity, density of shopping facilities, and the nearest distance to subway stations in some periods were generally flat; the spatial changes of building continuity and relative walking width were obvious in some periods. Moreover, population density and green vision rate had different spatial characteristics in different periods. This study restores the travel track of shared bicycles, analyzes the spatiotemporal characteristics of shared bicycle travel in multiple periods of working days and rest days and long-term series, and increases micro-built environment factors of subjective perception of people and experience dimension based on existing objective material space environment variables, to explore the spatiotemporal differences of the impact of different built environments on the travel flow of shared bicycles which compensate for the existing shared-bike travel time and space characteristics, build a shortage of environmental impact research, and provide references for the construction of an urban-friendly cycling environment and the creation of a slow walking space.

Northwest Hubei Province is a region prone to soil erosion. Investigating the spatiotemporal variations in soil erosion and identifying its underlying causes can offer valuable insights for guiding soil and water conservation efforts in the area. Based on the RUSLE model, we quantitatively analyzed the spatiotemporal variations in soil erosion in Northwest Hubei from 2005 to 2020. A geographical detector model was used to study the dominant factors of the spatial and temporal differentiation patterns of soil erosion, the degree of interactive coupling between multiple factors, and quantitative attribution of soil erosion-prone areas. The results indicate that, overall, the intensity of soil erosion in Northwest Hubei continued to decrease from 2005 to 2020. The average soil erosion modulus decreased by 16.3 t/(km²·a), and the soil erosion volume decreased by 200,000 t in 2020 compared to in 2005. Northwest Hubei showed a spatially divergent pattern of strong soil erosion intensity in the west and south and weak soil erosion in the central and north, with slight and mild erosion as a whole (accounting for 93% of the total erosion area). The land-use types in the study area were mainly forest land, and the proportions of forest land in 2005, 2010, 2015, and 2020 were over 60%. The soil erosion intensity of cultivated land was the highest among all land-use types. The area proportion of mild and above grade erosion intensity in this type was 85%, followed by forest land and grassland, with the percentage of the area of mild erosion intensity being 33.96% and 26.63%, respectively. From 2005 to 2020, each land-use type was transformed into another, and the transfer matrix results showed that cultivated land and grassland were mostly transformed into forest land, with a transfer area of 11.98%. Topographic factors markedly affected the soil erosion pattern: the soil erosion intensity in northwestern Hubei first increased and then decreased with the increase in elevation; the most significant erosion occured in the elevation zones of >200-500 m and >500-800 m, with proportions of the total erosion area being 47.7% and 31.8%, respectively. The soil erosion pattern was different under different slopes, and the area of >8°-25° was dominated by moderate, strong, and very strong erosion (the proportion of erosion is 55.4%); 65.6% of the area of >25° is strong and above high-intensity erosion. Given the impact of topographic factors on soil erosion, effective arrangements for soil erosion prevention and control measures should be made, keeping in mind the elevation distribution law and slope as the primary influencing factors. The results of geographical detection showed that slope and land use were the dominant factors affecting soil erosion, and the explanatory power of the two factors on soil erosion (q=0.479) was better than that of a single factor. Areas with slopes>35°, at elevations ranging between 500 and 800 m, showing an annual rainfall erosivity of 4,950.55-6,378.09 MJ·mm/(hm²·h·a), and cultivated land as the main land use type were identified as high-risk erosion areas. The results provide a scientific basis for soil erosion prevention, control, and land-use optimization in northwestern Hubei.

The phenomenon of population aging has become an important issue affecting the sustainable economic and social development of China's countryside, but few studies exist within the academic community on the sustainable livelihoods of rural elderly farmers in areas of poverty alleviation. Based on a 2022 field survey in Guzhang County, Hunan Province, this study examined the sustainable livelihood pathways of elderly rural farmers in these areas through non-participant observations, semi-structured interviews, and grounded theory methods of textual analysis. Study findings show that in the face of rural hollowing out caused by the outflow of the young labor force due to rapid urbanization, a large number of rural elderly farmers in poverty alleviation areas are facing the livelihood dilemma of rural pension structure constraints and the rational choice of agriculture. The background for this situation involves the insufficiency of the original pension model and multiple welfare sources, a shortage of medical and health service facilities, and the transformation of intergenerational relations. Therefore, based on the advantages of rural social networks in poverty alleviation areas in the three active aging dimensions of health, participation, and guarantee, this paper presents a sustainable livelihood research paradigm in which the individual, rural, and socioeconomic networks and rural production-living-ecological space of elderly farmers in poverty alleviation areas coordinate with each other. The paper also introduces a logical framework for the sustainable livelihood of elderly farmers that is consistent with the goal of rural revitalization through the thrust of nearby urbanization. Specific sustainable livelihood paths integrating individual spaces include the following: 1) at the individual level, through the individual livelihood behavior and livelihood capital of elderly farmers dynamically adjusting to the corresponding sources of welfare and livelihood modes with changes in the life cycle, 2) at the field space level, through the sixth industry, integrated development of modern factors intervening in the establishment of rural market industrial support to cope with aging, and 3) at the territorial space level, according to the rural elderly. The social circle structure of rural households is used to reshape the living, production, and ecological aging life circle. This study analyzed the sustainable livelihood paths of rural elderly farmers in poverty alleviation areas from individual to spatial perspectives The findings provide a theoretical basis and practical references for the revitalization of rural people in these areas in the era of rapid aging.