MODIS-EVI时间序列重庆夏季干旱研究

Research on the Summer Drought in Chongqing by Using MODIS-EVI Time Series Data

选取重庆市2000～2009年MODIS EVI时间序列数据,采用BISE去云处理方法,首先进行EVI时间序列的变化矢量分析,研究了EVI对干旱的响应情况;再选取4个典型区域,研究了2006年在干旱严重发生时EVI与气温、降水之间的关系;最后基于时间序列植被状态指数(VCI)和降水距平百分率研究了2006年重庆大旱的时空分布规律。结果表明:2006年重庆夏季EVI明显低于其他年份相应时间EVI的平均值;重庆市夏季旱情发生期间主要以高温少雨天气为主;除东南部外,其他大部分区域均处于严重干旱状态下。

MODIS-EVI time series data from 2000 to 2009 in Chongqing were selected for this study.By the use of best index slope extraction（BISE） method for cloud elimination,analysis on the change vector of EVI time series data were conducted to investigate the EVI response on drought;then,four typical regions were selected to study the relationship between precipitation,temperature and EVI when the sever drought occurred in 2006;finally,based on the time series of vegetation condition index（VCI） and precipitation abnormity percentage,the temporal and spatial distributions of drought were studied.The results showed that,the EVI value of the summer in 2006 was significantly lower than the average EVI at the corresponding period of the other years in Chongqing.In addition,summer drought occurred mainly during the hot and dry weather.Except the southeast area,most of the other regions in Chongqing were all under severe drought.