REMOTE SENSING DERIVED COMPOSITE VEGETATION HEALTH INDEX THROUGH INVERSION OF PROSAIL FOR MONITORING OF WHEAT GROWTH IN TRANS GANGETIC PLAINS OF INDIA

摘要

The present study proposed a composite vegetation health index (VHI) derived from Leaf area index (LAI), Chlorophyll content (Cab) and equivalent water thickness (Cw) of wheat crop in Trans Gangetic Plains of India. The wheat growing areas of the study area were retrieved from time series 16 days MVC MODIS Enhance Vegetation Index (EVI) data. The LAI, Cab and Cw were retrieved from MODIS reflectance (MOD09) through inversion of radiative transfer model, PROSAIL using Look Up Table (LUT) approach. The results revealed that LAI, Cab and Cw were very well retrieved with RMSE 0.3892, 4.307 and 0.0063 respectively. R~(2) values for all the three parameters were significant and were found to be 0.904, 0.917 and 0.894 respectively. A composite VHI was developed from LAI, Cab and Cw, values. Based on the VHI, wheat growing area in study region was divided into four zones. Wheat growing areas having VHI ranging from 0-0.25 and 0.25- 0.5 are classified as poor growth conditions. Wheat regions having VHI values from 0.5 to 0.75 and above 0.75 were classified as good and very good conditions respectively. The classified VHI map was compared with yield map of the study area and was found highly correlated.