Abstract:

The Poyang Lake wetland of China is in the first batch of the Ramsar Convention List of Wetlands of International Importance. Poyang Lake's surface area has decreased drastically in the past three decades, and hydrological droughts have occurred more frequently in the region in recent years. It is unclear which factors are responsible for the change and to what extent. This study utilized satellite remote sensing to investigate the recent increase of drought events in the region. The Moderate Resolution Imaging Spectroradiometer (MODIS) data were used to retrieve the lake variations in the last decade. The Global Precipitation Climatology Centre (GPCC) data sets were incorporated to analyse the water cycle in the basin. Our results revealed no significant increasing or decreasing long-term trend in precipitation. The lake surface reached minimum levels in the winters of 2003, 2006 and 2009, corresponding to three severe hydrological droughts in the basin. Case examinations showed less precipitation in 2003 and greater evapotranspiration in 2006, but this was not the case for 2009. The explanation is likely related to operation of the Three Gorges Dam, the largest dam in the world. Overall, the increased frequency of droughts was very likely related to the dam construction and operation and climate change, in addition to land-use and land-cover change.