Performance evaluation of two meteorological indices for drought assessment in Jalna

Drought is a creeping and recurring hydro-meteorological event, which originates from reduced precipitation, high temperature, and high evaporation over extended period of time. It is normal in any climatic region and, perhaps the most complex natural hazard, because it develops slowly, is difficult to detect and has many facets in any single region. Drought preparedness and mitigation depends upon timely information on drought onset, development in time and spatial extent. This information may be obtained through continuous drought monitoring, which is normally performed using drought indices. This paper describes drought assessment, using two different meteorological indices, RAI (Rainfall Anomaly Index) and SPI (Standardized Precipitation Index). The Marathwada region of Maharashtra was chosen as the study area and this region is characterized as a ‘frequently drought prone area’, where drought can be expected every 6 to 10 years. A comparison of RAI and SPI values were done for determination of drought severity and temporal extension of drought for planning of mitigation measures for farmers. Using the SPI and RAI as indicators of drought severity from 1901-2002, the characteristics of drought were examined. The maximum annual SPI was -2.61 in the year 1920 similarly the RAI values also showed the same results which was -4.748. Whereas in the month of June the SPI value was -2.09 in the year 1941 and the RAI value was -3.29, in the month of July the SPI value was -2.34 in the year 1971 and the RAI value was -3.85. The overall study shows that RAI is highly correlated with SPI for determining the characteristics of droughts in the study area. The overall outcome of this study demonstrates that extreme and severe droughts were experienced in the year 1920, 1972 and 1911, 1912, 1918, 2000, 2001 across the study area leading to unfavorable results on agricultural practices and water resources in the area.