Survey on Variability of Surface Wind Speed in Mega Cities over Iran

Wind is one of most complicated climatic elements with wide variety effects in different scales. Sudden increase of wind speed causes squalls and If they cause to trends and variability of wind speed in large scales and in small scales have been observed. There is less information on nature of spatial change of wind element respect to other climatic elements. Change of methods in wind observations, change in surrounding environment during the observing period due to relocations of meteorological stations, urban growth and change in vegetation cover of the cities cause wind data not to be homogenous. The above mentioned features hinders the study of wind variability, but nevertheless, study of wind variability is a necessity. The purpose of this paper is to find this variability in some of synoptic stations of Islamic Republic of Iran. Using some statistical methods, long term changes of surface wind speed (10 meters) in some synoptic stations for period 1951-2000 will also be presented. Tests of Cumulative deviationare are used Cramer, Mann- Kendal and Pearson to determine homogeneity, change point and trend of time series of wind data. Some change points are found in the series.