Application of microwave vegetation index in drought monitoring

For a vegetation-covered area,a Normalized Difference Vegetation Index( NDVI) is widely applied in drought monitoring by remote sensing. Compared with vegetation index based on optical remote sensing,the proposed Microwave Vegetation I ndex( MVI) provided additional information on vegetative growth. Temperature microwave vegetation index( TMVDI) was also developed using MVI based on Temperature Vegetation Dryness Index( TVDI) instead of NDVI. In the present study,drought that affected Sichuan province in the summer of 2006 was observed. Drought monitoring results based on TMVDI and TVDI were compared and then analyzed. We particularly compared the monitoring results obtained by remote sensing with those based on the standardized precipitation index established from the precipitation observation data of meteorological observatory to evaluate monitoring accuracy. These results also show that TMVDI,which is calculated on the basis of low-frequency microwave radiometer d ata( descending pass),is considered as the most suitable index that can be used to monitor drought in vegetation-covered areas.