THE DYNAMIC VARIATION CHARACTERISTICS OF GAHAI LAKE AREA BASED ON EOS-MODIS DATA

摘要

The 250m 16-day composite EOS/MODIS products (MOD13Q1) from 2000 to 2006 were chosen for monitoring annual and seasonal variation of Gahai Lake area. And the effects of meteorological factors on Gahai Lake were also discussed. The method of single band with threshold value was applied to lake extraction. The results showed that in 2000-2002 Gahai Lake often dried up, but the lake water appearance time advanced each year. Since 2003, Gahai Lake didn't drought up. The annual average, maximum and minimum area of Gahai Lake increased year after year. Due to some recovery measures, such as the Project "Zhongqu River Water to Gahai Lake" and the Project "Converting Grazing to Grassland", Gahai Lake area expanded quickly. Its seasonal variation presented peak-valley-peak trend, and the appearance time of peak value and valley value were different each year. In addition, Gahai Lake area was distinctly influenced by meteorological factors.