Simulation of climate change in Iran during 2071-2100 using PRECIS regional climate modelling system

Abstract

Parameters such as future precipitation, temperature, snowfall, and runoff were modeled using PRECIS regionalclimate modeling system in Iran with the horizontal resolutions of 0.44×0.44°C in latitude and longitude under SRESA2 and B2 scenarios. The dataset was based on HadAM3p during the periods of 1961-1990 and 2071-2100. Theoverall precipitation error of the model in the period of 1961-1990 was 5.3%. Minimum errors were found to be overAzari, north-central, and Kordi regions. Maximum and minimum monthly precipitation errors were found inSeptember and May, respectively; but, minimum and maximum seasonal biases were found in spring and winter with-0.1 and -17.2% errors, respectively. Results revealed a decrease in mean annual precipitation toward the end of the21st century by 7.8 mm in B2 scenario and 10.1 mm in A2 Scenario with maximum regional decrease of 100 mm inthe southeast of the Caspian Sea. The decrease in precipitation was higher for A2 scenario, whereas it was minimumfor B1 scenario. Mean annual temperature of Iran during 2071-2100 would be projected to increase by 4.5-5.5°C inA2 scenario and 3-4°C in B2 scenarios compared to 1961-1990. It was shown that mean annual changes in runoffover the country were negligible both in A2 and B2 scenarios. Maximum annual amount of runoff increase was foundover western part of the Caspian Sea, Zagros and Alborz mountain chains by 6.4-15. 8mm. Results also indicated thatannual snowfall would decrease by the maximum amount of 22.9-23.7 cm over Zagros and Alborz mountain chains.