中国新一代极轨气象卫星风云3号A星(简称FY-3A)上搭载的中分辨率光谱成像仪(MERSI)具有5个250m分辨率通道, 进一步加强了对地表精细地物的观测能力, 为大面积干旱监测提供了新的遥感数据源。利用 FY-3A/MERSI传感器250m分辨率数据和垂直干旱指数(perpendicular drought index,PDI)对2009年夏季内蒙古自治区中东部干旱进行了监测。结合气象部门的降水、温度和气象干旱资料对比分析表明, 基于250m分辨率的时序FY-3A/MERSI卫星资料反演的PDI干旱指数能够客观地反映研究区旱情的空间分布和动态发展过程。利用实地观测的土壤水分数据验证了PDI指数和土壤水分之间的关系。从验证结果看: PDI指数和对应实地观测的10cm、20cm土壤持水百分含量之间有较好的负相关关系, 其中PDI和20cm深度处的土壤持水百分含量之间的相关关系更为稳定, R2达到0.69以上。该研究表明利用中国新型、自主的FY-3A卫星资料进行干旱监测业务是可行的。

Medium Resolution Spectral Imager (MERSI) on board the new Generation Polar-Orbiting Meteorological Satellite of China (FY-3) has five spectral channels with 250m spatial resolution, which enhances the ability to observe fine surface features and provides a new data source for drought monitoring in large area. Drought status of north China is evaluated using FY-3A/MERSI satellite data with Perpendicular Drought Index (PDI). To validate the performance of PDI in macroscale appli-cation, quantitative evaluation of drought conditions and development in Tongliao and Chifeng, two cities located in southeast of Inner Mongolia Autonomous Region of China are carried out by comparing time series drought monitoring results with field observation data. Results show that drought status derived from PDI is highly accordant with field drought observation. Satellite based PDI has significant correlation with 10cm and 20cm depth soil water content. Compared with 10cm depth soil water con-tent, PDI has more stable relationship with 20cm depth soil water content. The drought monitoring application in this study show great potential in future drought monitoring operation using China’s own satellite data.