The Study of Daily Extreme Temperature and Precipitation in Urmia Lake Basin

For investigation of variability of climatic elements of Urmia Lake basin, maximum and minimum daily temperature and daily precipitation data over period of 1984-2006 were analyzed. In this paper, 6 indices for analysis of temperature variability and 8 indices for analysis of precipitation variability were used. The trends of these indices were specified using least square approach and for identifying their significance nonparametric, Man-Kendal test was used. Results indicate that over the study period climatic conditions have changed. The number of summer days and warm nights significantly increased with the number of cold days and cold nights reduction. Also total annual precipitation, number of precipitation days (above 2 mm) and number of heavy precipitation days (equal or above 10 mm) have significant reduction. Moreover, in the study period the number of consecutive wet days has significant reduction, but increasing of consecutive dry days is not significant.