| Poyang Lake is a typical wetland, with unique wetland hydrology, soils, ecological characteristics. However Poyang Lake is the driest climate in Jiangxi Province area, it is faced with drought problem in recent years. Though the river net is close, when there is a drought year, especially of consecutive drought year, rivers and lakes would be dry. The water resources of drought year was short, which posed severe threatens to the social and economic development of Poyang Lake, especially the agricultural production. Since 2003, Poyang Lake being to the continuous drought; Add the operation of Sanxia Project, the middle of Yangtze River and Poyang Lake's dry season water level are lower and lower, the duration of low water level was extend. Under the effect of dry, the lake water quality degradation, the degradation of plant communities, a significant reduction in aquatic and wintering birds. At the same time, the effect of dry had also has serious implications on economic and social development in urban and rural domestic water, agricultural production, irrigation, shipping, fish catch and so on. Under tremendous pressure, the Poyang Lake wetland ecosystem need appropriate management and protection.For the above, with the collected history data about the Poyang Lake's hydrological, meteorological and remote sensing, this paper has made processing and analysis; This paper made quantitative drought monitoring and analysis, by established the Poyang Lake area hydrology, meteorology, remote sensing integrated drought monitoring model which have a wide range of observations, informative, fast access to information, comparability of remote sensing technology, etc. The paper master of drought on the impact of changes in Poyang Lake wetland laws and explore the Poyang Lake wetland drought research methods and new technology means, through the analysis of the Poyang Lake wetland ecosystem and the variation under the arid state.The content and conclusions of the study as follows:1,The paper has systematic introduction to the theory of knowledge about drought, which contains the drought definitions, characteristics, four drought categories and drought indicator. At last, characterization of the drought Poyang Lake by select the precipitation anomaly index, water level indicator and vegetation water index.2,The paper established the vegetation water index model by vegetation index and land surface temperature, the water level indicator and precipitation anomaly index by the information on Xingzi county's water level and the daily rainfall data of Nanchang and Poyang; the paper has also propose the VSWI index and the quantitative classification of average precipitation from. Eventually, the paper has monitored the Poyang Lake drought by actual analysis, the remote sensing, hydrology, meteorology comprehensive model. That's use the water level indicator in the days 001～033,337～353; in 049～257 use vegetation water index; in the day 273～321 use precipitation anomaly index. The results indicate that it's feasible use this model to monitor the drought of Poyang Lake.3,The paper has monitor the drought conditions of Poyang Lake by the integrated model with remote sensing and hydrology meteorology. The results show that in the three years, Poyang Lake has drought in summer, autumn, winter and even in spring. The driest was in autumn. The most serious drought was 2007, the second was the year 2009, the third was 2008. It's more easy to drought in south of Poyang Land than the north of Poyang Lake. Around the Lake, the most easy to drought area contain Xinjian country. Jinxian country, Yugan country, the second Boyang country and Yongxiu country. Xingzi country, Jiujiang country, Dean country, Hukou country and Duchang country was seldom has drought, even has drought, also very light. It's has show that Water level, rainfall and vegetation water index VSWI has a positive correlation.4,Based on the statistical data of NDVI, water quality and agricultural, the paper has analysis the affect which the drought in 2007～2009 bring for the Poyang Lake's vegetation, water quality and agricultural, investigated the method for fight drought. The results shows that the drought will reduce the vegetation in the area, reduce water quality by decline the water body self-purification; reduce the living space of fish and then down the difficulty of fishing by reduce fish spawning and feeding grounds; reduce the number of migratory birds through reduce the food sources of birds and deterioration of bird habitats. In addition, drought has some impact on agricultural production and urban water supply. The methods of drought mainly from the engineering measures and non-engineering measures which include improve irrigation facilities, enhance engineering and ecological engineering meteorological drought, increase drought and drought awareness, develop water-saving agriculture, rational allocation and scheduling water sources, establish drought fund system and measures. |
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