Oct, p: 636-646. (In Farsi) The effects of climate change on DeMartone climatic classification in Golestan province

Increasing trend of greenhouse gasses in recent decades has affected weather and climatic zones across the globe. The aim of this study is to investigate the effect of climate change on climatic classes of Golestan province, Iran based on the extended de-Martone index. Rainfall data of 60 rain gauges and daily minimum/ maximum temperature data of 22 weather stations during period of 1982-2010 were used as baseline observations. Besides, HadCM3 model outputs were statistically downscaled using LARS-WG model under A1B ,A2 æB1scenarios to project rainfall and temperature data for three periods of 2011-2040,2041-2070 and 2071 to 2100.Generated time series of mean annual rainfall, mean temperature and minimum temperature of coldest month of the year were interpolated using Kriging method. Based on extended de-Martonne index, climatic zones were worked out and drawn using GIS tools. Results indicated that Kriging method interpolated rainfall data with less error comparing to other methods. According to the results both temperature and rainfall in the region would increase but the increase magnitude may vary in different periods, such that in near future (2011-20140) the rate of rainfall increase would be more than temperature which lead to more humid climates. This will be reverse during 2071-2100 in which drier years are expected. Among the chose scenarios, the A2 projects the worse conditions for the study region. Taking into account the temperature gradient, the Geographically Weighted Regression method is suitable for regionalization of temperature. Comparative examination of climatic zones of province under climate change scenarios showed that warm semi-arid climatic class which does not exist at present, would cover about 5 % of the province. in the last study period.i.e.2071-2100 under A2 scenario.