Trends in Biosciences

RISAT-1 is India's first indigenously developed C band SAR satellite. The present study was undertaken to retrieve surface soil moisture from RISAT-1 satellite data and comparing it with actual ground truth observations by using Topps model. The ground truth observations were carried out synchronized with satellite passes for two different location viz. Annur and Muthur for both Wet and Dry seasons. Two different locations are chosen as representative for Western Agro Climatic zone of Tamil Nadu. There is good correlation obtained between predicted and observed estimates. The soil moisture correlated with raster value obtained from Topps model for dry season showing less correlation coefficient (0.49 to 0.51) compared wet season (0.52 to 0.56). But the bulk density correlated with raster value obtained from Topps model for Dry season showing more correlation coefficient (0.24 to 0.43) compared to wet season (0.15 to 0.57) respectively. When we compared the estimated soil moisture values obtained from Topps model for Annur (0.50 to 0.56) and Muthur (0.49 to 0.55) locations, there is no significant different is observed. But when we compared the raster values obtained from Topps model with the bulk density there is significant different is between Annur (0.15 to 0.36) and Muthur (0.37 to 0.57) locations. It is found that the raster value from Toppsmodel during wet season having more nearness to actual soil moisture observations compared to dry season. While raster value from Topps model during dry season having more nearness to bulk density compared to wet season. There is no significant different is found in accuracy in estimation of soil moisture for two different locations. These results suggest that more research is required to suggest the suitability of Topps model for RISAT-1 data.