为探讨中国FY-3A数据对干旱旱情监测的差异性与可比性,结合植被供水指数VSWI(vegetation soil water index),利用Aqua/MODIS(moderate-resolution imaging spectroradiometer)数据作对比,实测站点数据作验证,对重庆地区2011年8月的旱情进行分析.2011年8月重庆市主要旱情级别为轻旱,干旱情况从西至东有减缓的趋势.从干旱级别来分,重庆西部主城区干旱情况最为严重,达重旱级别;重庆西部地区仍然受到中旱和轻旱两种不同干旱程度的影响;重庆中部大部分处于适宜植被生长的状态;重庆东北、东南地区最为湿润,不受旱情的影响.FY3A/VIRR植被供水指数数据与Aqua/MODIS植被供水指数数据的相关性达到0.7537.植被供水指数监测结果和实测数据呈正相关关系,与20 cm的实测土壤墒情数据相关性最高,FY-3A/VIRR、Aqua/MODIS与20 cm的实测土壤墒情数据的相关系数分别为:0.7768,0.8171,且均通过0.01的显著性检验,说明监测结果可信,即利用FY-3A数据进行旱情监测是可行的.另外,针对重庆地区的地表覆盖类型和地貌类型,将重庆地区细分4类:作物,小起伏地形的作物,混交林和中起伏地形的混交林,利用动态的旱情评定标准进行针对性旱情分析.发现植被供水指数法比较适宜大面积的旱情监测.%For the purpose of probing into the othemess and comparability of drought monitoring,by using FY-3A data,combining with VSWI(vegetation soil water index),comparing with the MODIS data and the confirmation data as the site data to analyze the drought condition of Chongqing in August 2011.The main drought condition of Chongqing in August 2011 was light and there was a tendency to slow down from the west to the east.As to the level of drought,the worst condition was in the urban area of western Chongqing,which reached heavy drought;moderate drought and light drought has effected western Chongqing,and the center of Chongqing was in a state of suitable for vegetation growth;the northeast and southeast of Chongqing were the most humid areas,not affected by the drought.The relativity of VSWI between FY-3A/VIRR and MODIS is O.7537.And the relativity of VSWI and site data is a positive correlation,the correlation with the 20 cm depth soil water content is the most stable one,which is 0.7768 and 0.8171 respectively.They all passed the significance test of 0.01,which illustrate the result's credibility,that's to say,using FY-3A/VIRR to monitor the drought condition is feasible.Moreover,aiming at the different land cover types and landform types,Chongqing is divided into four categories:crops,crop in little undulate terrain,mixed forest,mixed forest in moderate undulate terrain.Vegetation Water Supply index method is more suitable for the large area drought monitoring.
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