利用植被状态指数距平监测2011年长江中下游5省春、夏干旱

针对2011年长江中下游湖北、湖南、江西、安徽、江苏5省春、夏旱的发展过程和空间演变态势，利用2011年4~8月中分辨率MODIS每16 d合成产品MOD13A2-NDVI数据，构建植被状态指数距平（AVCI）进行干旱监测及分级。结果表明:AVCI指数能监测出长江中下游5省春、夏季干旱的发展变化，在整个监测期内，长江中下游湖北、湖南、江西、安徽、江苏5省大部分地区AVCI值偏低，出现大范围干旱持续的现象，并且表现出明显的旱情加重-旱情减轻-旱情再加重的变化趋势。前期春季干旱主要分布在湖北中东部、安徽中南部、江苏南部、湖南东北部、江西北部地区，后期伏旱则在5省大范围发展。春旱干旱程度比伏旱更甚，其中春季旱情在平原地区更为严重

MONITORING DROUGHTS IN THE FIVE PROVINCES ALONG THE MIDDLE-LOWER REACHES OF THE YANGTZE RIVER DURING SPRING/SUMMER 2011 USING AVCI

In view of droughts development and evolvement of Hubei,Hunan,Jiangxi,Anhui,Jiangsu provinces along the Middle-Lower Reaches of the Yangtze River in spring and summer 2011,based on MODIS images from April to August of 2011,normalized difference vegetation index(NDVI) from 16-days synthetic data MOD13A2 was used to build and calculate anomaly vegetation condition index(AVCI),which had been divided into five levels to monitor droughts.8 phases of drought spatial distribution of the five provinces along the mid-lower reaches of the Yangtze River has been gotten based on anomaly vegetation condition index(AVCI),which showed the evolution process of droughts in spring and summer,2011.The results showed that the AVCI index could effectively monitor spring and summer droughts in the five provinces.During the entire monitoring period,AVCI of most parts in the five provinces was low and turned up widespread continuous drought.It was clear that the droughts had the trend of aggravated-reduced-aggravated again from the sequence change maps of AVCI in these areas.Spring drought was mainly located in mid-east of Hubei,mid-south of Anhui,southern Jiangsu,northeastern Hunan,northern Jiangxi,while summer drought was spread over a relatively large area in the five provinces.It was found that spring drought was heavier than summer drought,and drought was more serious in plain area.