In this paper, a hypothesis about the origination and formation of the Zhanjiang bay is proposed on the basis of following arguments: 1) an event of meteorite impact might occurr on Zhanjiang area during the late Pleistocene epoch, and today’s Maxie Sea would be the impact crater ; 2) a large number of dust raised by the impact event flowed northward and deposited around the northern Zhanjiang, which formed a large area of eolian loess with about 50cm in thickness; 3) as a consequence of the impact effect, the Nansan. Island was separated into three islands, causing a number of volcanic activity in the area around the impact crater; 4) in the northern area of the Maxie impact crater, there was ‘X’ crack, which was eroded deeper and wider during the lower sea level period after the impact event and then became a drowned valley during the post glacial period of Holocene. This hypothesis is derived from observation on the following three aspects: First, what did the materials of the large area of eolian loess come from? Second, the Maxie Sea likes an impact crater with some unusual signs both in the impact crater and its surroundings. And third, the drowned valley of the Zhanjiang Bay looks like a rift valley.

This paper collected the historical tidal data and the actual loss data of storm surge disasters of the Pearl River Estuary, and made an analysis on the sea level rise values from IPCC-AR4 and some evaluation reports according to marine and hydrology standards. The analysis identifies that some papers have overestimated the effect of sea level rise on storm surge disaster forcasting of the Pearl River Estuary. The reasons are as follows: 1)There’re some errors in report [10]: a. AAL/GDP was defined as a linear relationship, GDP and AAL/GDP were used to compute AAL. That is logically wrong, because storm surge disaster loss does not increase year by year, and it is not directly related to GDP growth. b. The 2005 values of per capita annual income in Guangzhou and Shenzhen were both estimated to be $ 6193, which is a serious high valuation, about 50% higher than the actual value. c. The evaluated values of storm surge water level are obviously too high. 2) The following are the errors in [19] and [20]. a. the evaluation method to directly overlay the sea level rise value and return period tidal level is not scientific. b. The estimations of global sea level rise in 2100 have no basis. 3) The historical highest value of the recorded tidal level in [21] may be too high.

Salt tide is designated as the low salinity (0.5-10) water body mixing salty and fresh water on landward side of the estuary. The estuary “salt water” and oceans “brine” should not be equivalent or confused. It is inappropriate to take “salt tide tracing” as “saltwater intrusion”. The salt tide tracing upstream is that the estuarine material moves with the tide movement, that is essentially a passive act. The dynamic mechanism of salt tide tracing is relevant to the circular motion process that estuarine water and salt substance move in and out with the tide, or drain and retain in a month or a day. During the period from neap tide to moderate tide (in a month ) and that at the beginning of tide ebb (in a day), estuary is in the phase from retaining (moving in) to draining (moving out). Freshwater drains at surface layer, while salt water at bottom layer, forming an obvious stratification structure. Affected by the density current, salt tide at the bottom further traces upstream rapidly, and its salinity reaches the maximum. Best result can be achieved for lowering the salinity when spring tide is transforming into moderate.

在城市化快速推进的过程中，一些急功近利的短视做法给城市的可持续发展带来种种社会问题。文章以广东省为例，具体阐述了由城市化过程当中一些不当做法导致的种种潜在危机：“撤县设市”导致城乡不分，城市无限扩张，其必然结果是鲸吞农村，大量占用耕地尤其是优质耕地，环境污染加重，由此而带来的连锁反应是乱占耕地和拆迁改造激发各种社会矛盾，易地开发导致丘陵山区林地消减，水土流失加剧，农业危机四伏等。针对以上问题，提出以工业化促进城镇化，以现代化农业为依托，以农业基础为支撑，重建合理的行政区划体系，科学规划城镇，严格控制城镇用地，切实保护好农村农业，加强生态环境的保护和建设，保证社会的健康发展。

Greenway construction has positive impact on the regional tourism development. It adapts to the new trend of leisure tourism and enrich the forms and contents of tourism. Currently, many cities in China set off an upsurge of greenway construction. But in the construction less attention has been paid to greenways’ quality, management, supporting facilities and their connotation enrichment. Aiming at those problems the author made field survey on the greenways of Shenzhen, Guangzhou, Dongguan, Huizhou and Zhongshan in the Pearl River Delta, as well as those of the country parks in Hong Kong, and put forward some suggestions to solve the problems and maximize the comprehensive benefits of greenways: (1) layout of the networked greenway systems; (2) construction of ecological greenways; (3) diversification of the greenway features; (4) humanization of the facilities; (5) scientific management; (6) diversification of the activities on the greenways.

In this paper, a hypothesis about the origination and formation of the Zhanjiang bay is proposed on the basis of following arguments: 1) an event of meteorite impact might occurr on Zhanjiang area during the late Pleistocene epoch, and today’s Maxie Sea would be the impact crater ; 2) a large number of dust raised by the impact event flowed northward and deposited around the northern Zhanjiang, which formed a large area of eolian loess with about 50cm in thickness; 3) as a consequence of the impact effect, the Nansan. Island was separated into three islands, causing a number of volcanic activity in the area around the impact crater; 4) in the northern area of the Maxie impact crater, there was ‘X’ crack, which was eroded deeper and wider during the lower sea level period after the impact event and then became a drowned valley during the post glacial period of Holocene. This hypothesis is derived from observation on the following three aspects: First, what did the materials of the large area of eolian loess come from? Second, the Maxie Sea likes an impact crater with some unusual signs both in the impact crater and its surroundings. And third, the drowned valley of the Zhanjiang Bay looks like a rift valley.

This paper collected the historical tidal data and the actual loss data of storm surge disasters of the Pearl River Estuary, and made an analysis on the sea level rise values from IPCC-AR4 and some evaluation reports according to marine and hydrology standards. The analysis identifies that some papers have overestimated the effect of sea level rise on storm surge disaster forcasting of the Pearl River Estuary. The reasons are as follows: 1)There’re some errors in report [10]: a. AAL/GDP was defined as a linear relationship, GDP and AAL/GDP were used to compute AAL. That is logically wrong, because storm surge disaster loss does not increase year by year, and it is not directly related to GDP growth. b. The 2005 values of per capita annual income in Guangzhou and Shenzhen were both estimated to be $ 6193, which is a serious high valuation, about 50% higher than the actual value. c. The evaluated values of storm surge water level are obviously too high. 2) The following are the errors in [19] and [20]. a. the evaluation method to directly overlay the sea level rise value and return period tidal level is not scientific. b. The estimations of global sea level rise in 2100 have no basis. 3) The historical highest value of the recorded tidal level in [21] may be too high.