Standard Precipitation Index (SPI) analysis in Karoon 3 Watershed under climate change

The aim of this study is to investigate climate change impact on Karoon3 basin in future periods. For this purpose, the simulated precipitation of 10 AOGCM models, including BCM2.0, CGCM3T63, CNRMCM3, CSIROMK3.0, GFDLCM2.0, GISS-ER, HADCM3, INMCM3.0, IPSLCM4, MIROC3.2 MEDRES was used to simulate drought index. Monthly precipitation was calculated by inverse distance weighted method. Standard Precipitation Index (SPI) was used as watershed drought index. SPI was calculated in 6, 12 and 24 months periods. To determine the feasibility of future periods meteorological data production of LRAS-WG5 model, calibration and verification was performed for the base year (1980-2007). Meteorological data simulation for future periods under General Circulation Models and climate change IPCC scenarios was performed and then the drought frequency and intensity using SPI under climate change effects analyzed. Results showed that normal and wet SPI category is more frequent in B1 and A2 emissions scenarios than A1B. Results showed that difference between maximum and minimum monthly temperature will decline in spring and summer. Drought years are more frequent under A1B and in 2080-2099 periods.