Abstract:
Tharparkar is an arid region in south eastern province of Sind, Pakistan and experienced drought as a regular phenomenon in the past. Fragile agro-ecosystem of Tharparkar is highly depended upon monsoon rain. Seasonal variability in monsoon can inflict heavy human and livestock loss. There was a need to characterize drought severity across Tharparkar to provide early warning of drought for provincial government to undertake appropriate measures with onset of drought. Complex nature of drought and sparsely located network of met stations handicapped reliable spatial and temporal analysis of drought severity across Tharparkar. Freely available Tropical Rainfall Measuring Mission (TRMM) rainfall satellite data and moderate-resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) satellite data fulfilled this gap and were used to generate drought indices. This study developed a new drought index called “standardized normalized vegetation index (NDVI) anomaly” and compared with traditional indices i.e. standardized precipitation index (SPI), standardized precipitation and evapotranspiration index (SPEI) for modeling drought severity condition in the arid and fragile agro-ecosystem of Tharparkar. The standardized NDVI anomaly data significantly correlated with meteorological drought indices (SPI, SPEI) and revealed vegetation dynamics under rainfall and temperature variations. The weighted overlay analysis in geographical information systems (GIS) depicted accurate onset of 2014 drought across Tharparkar. This study provided useful information for drought characterization with newly developed drought index that can be used for drought monitoring and early warning system in the data scarce arid and semiarid regions.
