Atmospheric pollution has been one of global environment pollution issues. PM2.5 and PM10 are the hot spots in remote sensing research of atmospheric particulates. The representative megacities in China, Beijing, Shanghai and Guangzhou, are the focus in related research field. Taking Guangzhou as an example, this paper analyzed the related domestic and international literatures, described the situation and limitation of the surface monitoring stations. It was pointed out that one of the important approaches of atmospheric particulate remote sensing including PM2.5 would be the regional atmospheric modeling system based on vertical correction model of airosol optical thinkness and moisture effect correction of near-surface extinction coefficient in regional scale.
This paper studied the statistic method of particulate matter concentration derived from the combination of the monthly average data of satellite-observed aerosol optical thickness, the predicted data of regional atmospheric model and ground measurement data. Firstly, the simulated Planetary Boundary Layer height was used to correct the monthly average Aerosol Optical Thickness resulting from MODIS data in 2006 in order to get the atmospheric extinction coefficient, which then was further converted to dry extinction coefficient by relative humidity data from RAMS and hygroscopic growth factor. Secondly, the particulate matter PM10 and PM2.5 statistic models were derived by combining the dry extinction coefficients with the ground station measurements in PRD. Finally, the models were validated by using monthly average MODIS AOT data and in situ measurement data from 16 ground stations in 2008 in PRD. The results showed that the predicted particulate matter concentration was consistent with the in situ measurements. It is concluded that the statistic method based on satellite observations combining with ground station measurements can be used to predict particulate matter mass in PRD.
A CE318 automatic sun tracking spectrophotometer was used to measure direct solar radiation at Guangzhou in 2011. The volume concentration, number concentration, volume distribution, number distribution were inverted, of which the annual and seasonal characteristics and the diurnal variation were studied. The results show that: 1) The volume concentration of aerosol at Guangzhou varied seasonally, with a spring maximum and a summer minimum, and the average value of the concentration in 2011 was 0.45 μm3/μm2. The correlation coefficient between volume concentration and turbidity was 0.956. 2) The volume distribution was in a bimodal pattern, while number distribution in a unimodal pattern. Fine particles whose radiuses within 0.1μm were the principle aerosol particles, composed of water dissoluble particles and soot, the main source of which were traffic pollution and industrial pollution. 3) With soluble particles and soot as major composition, and a small number of sand and marine aerosol particles besides, aerosol pollution at Guangzhou was mainly relevant to man-made pollution, such as industrial pollution and traffic pollution. 4) The diurnal variation of particle concentration at Guangzhou was consistent with that of human activities, rising with the increasing of human activities. The concentration of fine particles at the period from 12 o’clock to 15 o’clock increased because of the strong solar radiation.
A CE318 automatic sun tracking spectrophotometer was used to measure direct solar radiation at Guangzhou in 2011. The Aerosol Optical Depth (AOD), wavelength exponent (α), turbidity (β) were retrieved, of which the annual and seasonal characteristics and the diurnal variation were studied. The results show that: 1) The average value of AOD at Guangzhou in 2011 was 0.53, which was at a relatively high level. The AOD varied seasonally, with a spring maximum (0.81), autumn and winter next (0.5)and a summer minimum (0.43). The turbidity had the same feature with the AOD. 2) The proportion of the wavelength exponent above 1.2 was nearly 90% in terms of frequency distribution, while that between 1.4~1.6 was more than 50%. That showed that the fine particles were the principle aerosol particles. 3) The wavelength exponents in autumn and winter were both larger, the values of which were 1.46 and 1.50 respectively. The value of wavelength exponent in spring was 1.27, while that in summer was 1.13. The coarse particles increased in spring and summer. Overall, the aerosols in Guangzhou were the mixture of the industry-urban aerosol and the maritime aerosol. 4) The diurnal variation of AOD at Guangzhou was consistent with that of human activities, AOD was continuously rising in the morning, and reached a peak at 13 o’clock, then tended to be stable, and it rose slowly from 17 o’clock on. The wavelength exponent had no obvious relationship with AOD.
Soil classification is an important work of soil remote sensing. In this paper 215 soil samples collected from paddy field in Guangdong Province were studied. Firstly, the soil spectra of 350-2 500 nm were measured by using ASD Field Spec 3, and the S-G first derivative smoothing was applied to reduce the effects of illumination difference. Secondly, the Genetic Algorithm and Support Vector Machine were used to select the spectral features and construct the soil classification models, respectively. The soil classifications were implemented at 3 different levels (soil order, soil suborder and soil type). The results indicated that in all classification models, the spectra of 650-710 nm and around 900 nm closely related to ferriferous oxide and spectra around 2 207-2 237 and 2 377- 2 397 nm closely related to metal-OH were selected. And for finer soil classification, more spectral variables were used. Even at the soil type level, the spectral data around 2 080 nm sensitive to the variety of soil organic matter were also introduced in the calibration model. The agreement rates at levels of soil order and soil suborder were above 67%, and that at level of soil type was 58.67%. The Genetic Algorithm and Support Vector Machine presented some advantages in soil classification.
The emerging unmanned aerial vehicle (UAV) remote sensing is an important supplement to traditional aerial and satellite remote sensing due to its flexible, fast and cost-effective capability for acquiring very high spatial resolution imagery. In this study, we explored the application of UAV to monitoring mangrove forests. The study area is located in the Yingluo Bay, on the borders between Guangdong and Guangxi Provinces. Using the UAV, we collected aerial photos of the coastal zones of Yingluo Bay, covering an area of 25.29 km2 with three flight missions totaling 2.5 hours. The high-resolution aerial images were first mosaicked and then used for interpretation and classification of mangrove forests. A typical sample plot of the study area was selected to conduct classification of mangrove species using object-oriented classification method with the nearest neighbor classifier. The classification accuracy of visual interpretation of mangrove forests extraction and that of object-oriented nearest neighbor analysis for mangrove species classification were both higher than 90%. We also compared our approach to conventional technology of aerial and satellite remote sensing for monitoring mangrove wetlands. Results suggested that UAV would be a good choice for mangrove research. It is promised that UAV would become a popular and useful tool for researchers and government agencies to contribute to mangrove reservation and management.
It is very import to delimitate red line of ecological protection for territorial spatial planning. This paper proposed a quantitative framwork to delimit red line of ecological protection. First, we defined biodiversity, flood storage, conservation of water and soil, headwater conservation and desertification control as the main factors to ecological problems at the provincial scale. Then, based on the theories of ecological service and security, core elements were chosen for analyzing the ecological problems referring to the requirements of macro decision-making, participatory "bottom-up" method was further utilized to map the ecological red line. In this model, main ecological problems and most sensitive areas in territorial space were identified by the means of “top-down” method. And then the red line of ecological protection was delimitated by using "bottom-up" model integrating GIS with RS. Hunan province was selected as the case study area to delimit the red line of ecological protection using the proposed framework. Three scenarios (i.e. ecological protection at low level, at medium level, and at high level, respectively) were set for analyzing the distribution of each individual ecological element. Results indicate that medium-level protection scenario is befitting for delimiting red line from the perspective of biodiversity. Ecological corridors is required to be further conserved on the basis of present conservation areas; whereas low-level protection scenario was selected for flood storage, Dongting Lake and its inundated area should be included in the protection region; and the spatial pattern of headwater conservation shows great difference. The large-scale mountains in the east, west and south parts have high values while the hills in the central part as well as the plain in the north show low values of headwater conservation; As for conservation of water and soil, mountains such as the Wuling, Xuefeng in the west and the Luoxiao in the east, which are especially the transitional zones to plain, are the areas accompanied with frequent water and soil erosion. With the consideriation of evaluation results above, the red line of ecological protection in Hunan province was generated. Approximately 50% of the total area is classified into the scope of the red line, which plays important roles in ecological security. The red line breaks the administrative boundaries of counties to some extent, but keeps the integrality of physical geographic boundaries and particularly lays stress on ecological protection. The delimited region of the red line presents a network pattern in the space and conforms to the strategic layout of “one lake, three mountains and four rivers” of the province. The delimitation results of Hunan province demonstrate that the method can obtain a reasonable spatial pattern for ecological protection at provincial scale.
In recent years, the urbanization in China that emphasized the development of core cities made the local cities gradually marginalized. The local cities has an important position and role. And it has become an important project which further advances the development of the new urbanization. In this context, taking Guangdong Province as an example, this paper tried to define the local cities and evaluate and classify the urbanization level with the method of entropy and cluster analysis, so that can explore the development path and possibility of the local cities under the background of the new urbanization. The results showed that: There are 15 local cities in Guangdong Province. Zhonshan City has the highest urbanization, but Maoming City is the lowest. And there is obvious difference of development level among the local cities. According to the urbanization level, the local cities can be divided into 5 categories. Each category has the different development characteristics. Under the policy concept of the new urbanization, the local cities have new chances to develop and can be expected to go various development paths according to local conditions and their connotation and advantage, for example, Zhongshan City should go a comprehensive development path to improve the whole urbanization, Meizhou City should excavate the content to reflect its characters, Heyuan City should go a ecological and green development path, Maoming City should improve the level of its infrastructure and public service and enhance its innovation ability.
Cellular Automata has proved to be a convenient and effective tool for simulating urban land use change, in which transition rules and neighborhoods configuration are the key issues. This paper presents a neighbor decay cellular automata model based on Simulated Annealing (SA-NDCA), which uses simulated annealing (SA) to find transition rules and considers the decay effect of the cellular neighborhood. A negative power exponential function is used to compute the decay coefficient of cellular neighborhood in the model. With calculating the cumulative differences in simulating results and the sample data, the simulated annealing optimization automatically searches the optimal combination of parameters of transition rules. By using Xiamen City as a study case, the peri-urban landscape dynamics of the period 1995-2010 is simulated with the model. For further evaluating the model performance, this study computed model accuracy by confusion matrix and Kappa coefficient. During the period from 1995 to 2010, the simulation accuracy for built-up land was 68.5%, and the overall accuracy was 86.2%, while Kappa coefficient reached 66.3. It was a relatively high level as compared with other researches. This study shows that the simulation results of SA-NDCA model can achieve a relatively high prediction accuracy of construction land, overall accuracy and Kappa coefficient. The neighbor decay cellular automata model based on simulated annealing optimization is very suitable for simulating the land-use changes in peri-urban area, as the model simulated well the characteristics of the intensive distribution of construction land development in the study area.
Today, the Free Economic Zone (FEZ), as the product of economic globalization and regional economic integration, has served as a significant platform for the reform of related institutions and a growth pole, which accelerates regional development. The Free Economic Zone features sustaining increase of numbers, diversification of types, far-reaching impact, synthetic functions, and more efficient management and administration. During the past 170 years, especially since World War Ⅱ, Hong Kong Freeport has been considerably enriched and perfected with the expansion of its function, and grown into one of the most open and inclusive freeports in the world. Most of the recent researches concentrate on the static analysis of the history, function, free economic policies of Hong Kong Freeport while the dynamic analysis of its development and the motivation fails to attract enough critical attention. This paper is begun with the retrospection of the emergence of the freeport, the three stages of transformation of the freeport by focusing respectively on manufacturing, synthetic and cross-regional types and related rules. Location, management mechanism, frame of policies and structure of industries are categorized as internal factors while the international economic, political and cultural environments are considered as external forces. The combination and interaction of the internal and external forces constitute the motivational mechanism, which propels the progress of the freeport. Finally，this paper has also discussed the Enlightenment of Hong Kong Freeport to the construction and development of China free trade zones: 1) The corresponding development pattern should be adopted according to its developing stage and conditions. 2) The Free Trade Area should be constructed in location of favorable locational condition. 3) Relatively stable political environment and administrative district become the essential conditions of promoting the sustainable development of free trade port and area. 4) The full function of the free port zone depends on a free economic system and the emulational international operation. To some degree, this paper enlightens the theories related to the perfection of free economic zone and the establishment of China free trade area.
The development of recreational space of city is closely related to the expansion of urban space structure and the development of city industry. Taking Foshan as an example, this paper reviews the development and evolution process of Foshan leisure space from a historical perspective. Before the Ming and Qing Dynasties, under the background of the development of commodity economy, the markets, streets, rivers in Foshan became the exchange centers of urban economic activity, the markets were prosperous, the residents’ leisure life in the commodity trade gradually sprouted, and the rudiment of leisure space formed. During the Ming and Qing Dynasties, as the commercial centers established and land use patterns changed, the urban space expanded and the leisure space became an important part in the life of the residents. Since China’s reform and opening up, the leisure space of Foshan city has been expanded comprehensively. Under the background of urban renewal, on the basis of local tradition and memory, Foshan government pays attention to the repair and renovation of leisure space, and the improvement of the declining old city area, promising to provide a common recognition and the same historical and cultural sense, so as to promote the communication of leisure space with the historical urban block.
Two hills in a typical Karst hilly area in Jiulong, Yingde, were selected as the study area. To understand soil calcium element migration and enrichment in different geomorphic conditions in Karst area, the bareness rate of rock, soil thickness and vegetation at hill top, cliff, slope, dry gully, hill foot and water depression were surveyed, and different soil samples were collected. Atomic absorption spectrophotometer was used to measure the contents of total calcium, exchangeable calcium, and water soluble calcium. The results showed that the total calcium content of soil in water depression was 62.397 g/kg, the highest in all the geomorphic locations, next were hill top, slope, cliff, and gully successively. The highest contents of exchangeable calcium and water soluble calcium also occurred in the soil of water depression, which were, respectively, 4.582 and 0.223 g/kg. The contents of exchangeable calcium and water soluble calcium were not significantly different at hill top, slope, cliff, and gully, which were 1.560-2.421 g/kg and 0.057-0.180 g/kg respectively. The research indicated that soil carbonate content and pH value had significant positive correlations with total calcium, exchange calcium, and water soluble calcium. There were significant positive correlationship between total calcium and exchange calcium, and between exchange calcium and water soluble calcium. It was shown that terrain affected not only the horizontal but also the vertical distribution of soil calcium.
Swimming is a popular activities for the beach tourists. In recent years, a large number of beach drowning accidents occurred in China, which were mainly caused by the rip currents. In this paper, a beach safety evaluation model is established based on the beach morphodynamic state model. The paper considers that low tide bar/rip and barred beaches have highest probability of rip currents, barred dissipative beaches and low tide terrace with rips beaches have medium risk of rip currents, and low tide terrace without rips, non-barred dissipative, ultra-dissipative and reflective beaches have low probability of rip currents. The model is used to evaluate the beach rip currents risk at Dadonghai, Sanya. The results show that Dadonghai beach has low tide bar/rip and barred beach states and has high rip current risk which accords with the local life-saving practices. This model can provide guidance for the beach safety evaluation and bathing beach management.
Xingfengjiang Reservoir (XFJR) is the greatest reservoir in Guangdong Province, China. XFJR provides drinking water for a population of 40 million in Huizhou, Dongguan, Shenzhen, Guangzhou and Hong Kong, which have a big portion in economic development of China. At present, water quality of XFJR maintains I type of environmental quality standards for surface water. However, with the fast economic development in the Pearl River Delta and the upriver areas, human activities have become intense and environmental problems become increasingly serious, which may directly influence water quality and quantity of the reservoir. In 2007 and 2008 we collected water samples from upriver watercourse of XFJR and analyzed the nitrogen and phosphorus pollution. The results showed that, nitrogen and phosphorus pollution was more in dry season than that in wet season at time scale, and more in residential area near cities and towns than in rural area at spatial scale. The results indicated that the main pollution was from point source pollution, including domestic sewage and breeding wastewater discharging. The risks of water quality deterioration exist in upriver watercourse of XFJR, which may lead to ecological problems, such as eutrophication and external biological invasion. It is suggested that water quality of the upriver watercourse of XFJR should be monitored regularly so as to protect the stability of water quality of XFJR and reduce the risks of deterioration of drinking water source.
This paper using frequency method, elaborates analysis on evaluation index system of karst ecosystem service value. Taking Huajiang Gorge of Guizhou Province as example, we have constructed the evaluation index system of rocky desertification ecosystem service value which is sourced from environment characteristics, ecological function location and other factors. And on the basis of actual survey data, we have used the physical and value assessment methods to evaluate ecosystem service value of Huajiang gorge in 2010. The results show that: The overall ecological service value of the demonstration area was 196 047.1×103 Yuan, consisting of 111 812.5×103 Yuan of CO2 solidification and O2 release value, 30 515.6×103 Yuan of soil fertility value, 28 504×103 Yuan of product supply value, 25 211.3×103 Yuan of water conservation value, and 3.7×103 Yuan of soil conservation value. The indirect values contributed the most to the overall value of ecosystem services, which accounted for 85.5% of the total, while the direct values accounted for only 14.5%. Ecological function value was mainly provided by shrub, economic forest, farmland and woodland ecosystems, and the bare rock slopes showed low service value, though they were the dominated landscapes in the study area.
Freshwater lens is an important groundwater resource in coral reef islands, and is essential to meet people’s needs and maintain the ecosystem of the island. In this paper, researches on the freshwater lens in the coral reef island are reviewed, including its theory and characteristics. Some factors related to the development of the freshwater lens are summarized, such as, those of hydrogeology, climate, tide, topography and vegetation of the island. The threats from natural and human activities are more serious to freshwater lens than before and need more attention, for example, drought, seawater intrusion, sea-level rising, mechanic erosion of the island, over-drawing of fresh water, pollution, the changes of the landform and coastal construction, etc. may cause damages on freshwater lens. In this paper, some models used in the study of the freshwater lens are described, such as physical models, analytical models and numerical models. The study of the freshwater lens in China is also introduced. Most researches are focused on Yongxing Island of the Xisha Islands. The study contents involve the thickness of the freshwater lens, its changes with rain, the up-coning of the interface caused by withdrawing of the groundwater, and bioremediation of the freshwater lens. Finally, prospect for the study of the fresh-water lens in coral reef islands is given in the paper. It is suggested that more islands in the South China Sea should be studied, and techniques to clean the pollution of groundwater and make the water drinkable should be developed.
Geotourism is an important part of natural tourism and ecotourism. Since the 1970’s, Geotourism has attracted the attention from various countries all over the world and has become an important new type of tourism. This paper tries to make an analysis and summary of the concept, subjects, object, medium, geopark of geotourism as well as the study of existing geotourism. In the research content, the researchers have paid more attention to the application problem and focused on geological tourism resource and geopark at home and abroad. There is a gap on basic theory of geotourism between domestic research and foreign research. As for the research perspective, the researchers mostly analyze issues with the theories and methods of earth science. The research method is generally based on qualitative analysis, while quantitative analysis is gradually increasing. The authors of this paper hold the view that we should strengthen the research on basic theory of geotourism, advocate multidisciplinary crossover study, pay attention to the application of technology, and enhance research of geotourism spatial entity.
With efficient performance, Digital Terrain Analysis (DTA) has been the predominant means of terrain analysis in landslide researches. Based on previous landslide literature, this paper reviews the basic application of DTA in landslide studies, including analysis of terrain factors, analysis of topographic morphology, terrain unit partition, and coupling analysis of DEM and landslide models. There are various applications of terrain factors, whose relationship with landslides is widely studied so as to assess their susceptibilities to landslide and then build prediction and elevation models. Analysis of topographic morphology intends to distinguish and recognize desired landslide terrain from normal terrain. It is possible to recognize the relief forms readily developing to landslides with further study of the correlation between specific terrain forms and landslides. Unit network partitioned by DTA may serve as elementary zones for statistics or other analysis. In more than one way, DEM is frequently incorporated into many landslide models in need of terrain information. Besides basic applications, we discuss scale issues of DTA in landslide studies, involving scale selection and transformation. Limitations of DTA are individually discussed, with the conclusion that DEM fails to characterize complete topographic features of landslides and thus DTA is unable to completely replace conventional terrain analysis method. At last, we propose 4 aspects to be further improved, including: 1) developing DTA-assisted 3D geological models for landslide numerical analysis; 2) probing into the relationship between topographical factors and geomechanical parameters; 3) enhancing the application of LiDAR in landslide studies; 4) analyzing the scale effects of DTA in landslide studies and normalizing rules of scale selection and transformation.
