利用EOS/MODIS数据,采用最佳波段组合指数法和方差-协方差矩阵特征值法,从36个MODIS波段中筛选出用于沙尘暴图像最佳彩色合成增强的最佳组合波段。在敏感性差异分析的基础上应用波段数学组合的方法建立了沙尘暴判识的条件:构建了提取沙尘暴区域范围和强度等级信息的沙尘暴卫星遥感监测指数SVI(Sand storm value index),利用指数SVI值的大小对沙尘暴进行了等级的定级和分类。
The Ebinur Lake and its peripheral regions are the important wetlands in Xinjiang. However, its lake bed is recently dried up in large area. Analyzing from the data monitored by EOSVMODIS satellite, the water area of the Ebinur Lake has been sharply reduced since summer 2006, its lake bed has been dried up in large area since late-July, and such situation became more serious up to mid-August. According to the data monitored by EOS\MODIS satellite, the water area of the lake was 550.6 km2 on August 19, 2006, and it was reduced by 263.4 km2, 126.4 km2 and 158.4 km2 comparing with that in late-July and early-August 2006 and mid-August 2005, respectively.According to the data monitored by EOS\MODIS satellite, the water area of the Ebinur Lake fluctuated in a range of 700-1 000 km2 during the period from April 2002 to July 2006, and it was larger than 1000km2 during the period from the end of spring to early summer 2005 (Tab.1). However, the water area of the Ebinur Lake was reduced to 550.6 km2 in mid-August 2006, the lake bed was dried up in large area, and the water area was the smallest since recent 4 years.
