Analyzing and predicting climate change impacts on drought using comprehensive drought indices

This study examines past drought conditions for the Arkansas-Red River Basin using the Standardized Precipitation Index (SPI), Palmer Drought Severity Index (PDSI), and Standardized Runoff Index (SRI), and predicts future drought occurrence using the same indices for the 21st century. Historical climate data from 1900-2009 were used to drive the drought indices calculation, and projected A2, A1B, and B1 climate data from 16 statistically downscaled Global Climate Models (GCM) were applied to predict drought frequency and areas affected for the 21st century. The results from SPI, PDSI, and SRI show that widespread drought took place in the 1910s, 1930s, 1950s and 1960s, which reconciles with the historical climate record of the U.S.. Predictions from the three indices vary on some level. PDSI and SRI indicate more frequent and more severe drought under A1B scenario, while SPI doesn't display such change of frequency under the same scenario. PDSI and SRI both suggest more intensive drought taking place after 2050 and the drought will occur now and then until the end of the century. SPI 12 month scale in this case captures the 2050s prediction and less duration drought is predicted now and then after 2050. The results from the three indices need to be verified with more study, and the expected outcome from this research should have tremendous implications in regional water management and could assist minimizing agricultural loss due to drought.