Evaluation of MODIS and TRMM Satellite Data for Drought Monitoring in the Urmia Lake Basin

The aim of this study was to evaluate the capability of remote sensing data for drought monitoring of Urmia Lake Basin (ULB). For this purpose, the MODIS NDVI/LST data and TRMM satellite rainfall data were downloaded on monthly scale from 2000 to 2014. After data processing, drought indices including Temperature Condition Index (TCI), Vegetation Condition Index (VCI), Precipitation Condition Index (PCI), Composite indices include CI1, CI2, CI3 and Vegetation Health Index (VHI) were calculated for March to September (growing season). To validate the mentioned indicators, Standardized Precipitation Index (SPI) on different time scales (3, 6 and 9 months) was used. Results showed the VCI is the favorable satellite index for monitoring agricultural drought of the ULB during the growing season. SPI3, SPI6 and SPI9 have the highest correlation with the VCI and VHI in March, with PCI and CI1 in April, with TCI, CI3 and CI1 in May, with VCI in June and July, with TCI and VCI in August and September, respectively. Composite indicators presented better results than VCI and TCI in May and April. Therefore it can be concluded that composite indices can provide better results during the wet months (May-April). Also, Drought Severity classification results of the ULB based on VCI showed that highest drought with 93.85, 91.93 and 72 percent in 2000, 2008 and 2001, respectively, and the lowest drought with 1.21, 2.06 and 5.33 percent in 2010, 2007 and 2004 respectively has happened during the growing season (March to September) in the ULB. Using the optimum satellite indices presented in the present study, it is possible to predict and estimate the drought phenomena of Urmia Lake BASIN in different months of the growing season or during the growing season and obtain a better result.