Evaluating the impacts of climate change on the diurnal temperature range (DTR) in southeastern of Iran using the outputs of AOGCMs

Abstract

Changes in global diurnal temperature range (DTR) areas are useful indicator of climate change. The present study aims at evaluating the impacts of climate change on DTR in southeastern of Iran by using 15 models of Atmospheric-Ocean General Circulation Model (AOGCM). Daily time series of parameters of minimum temperature and maximum temperature and the rainfall during the period were initially extracted. By making use of the aforementioned 48-year time series, the input for model LARS-WG was prepared. The model, then, was calibrated. By comparing changes in the next period to the previous one, impacts of climate change on variability of climate parameters affected by AOGCM were evaluated. Verification results of the minimum temperature and maximum temperature components showed that models HadGEM and GFCM21, respectively, are the most appropriate models for simulating the temperature components, with the least mean absolute error. Data analysis showed that the average hot days on the next period will increase then the base period and the average frost in the next climatic period will decrease in all months than the base which itself is a reason to increased average of minimum temperature component over the maximum one in the next climatic period. At the end, results obtained from investigating the impacts of average temperature components during the year showed that climate change in summer and autumn reduce the DTR on southeastern Iran. The maximum reduction in DTR occurs in late summer and mid-autumn.