In order to analyse spatial and temporal trend of extreme Warm days of Iran, mean daily temperature data from 663 synoptic and climatologic stations of Iran for the period 21/03/1961 to 31/12/2004 were used. Then, applying Kriging method, the temperature of 15*185 Km pixels was interpolated. The days accompanied with extreme warm were identified using Normalized Temperature Departure (NTD) index. According to the index, the days with NTD 2 selected as extreme warm days. Then a trend analysis applied to the extreme warm days for each month of year. The results show that the number of extreme warm days in Iran represents no trend in December, February and March. East ,south, center and southeast parts of Iran show positive trends during August, January and May over large areas. While in north and west of the country over small areas negative trend was observed during Mars and February.
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