Estimation of wind stress in the western and northwestern regions of Iran

In this study, in order to investigate the general conditions of wind stress in the west and northwest of Iran, wind stress and velocity data at an altitude of 10 meters above the ground from the MERRA-2Model database of the TRMM sensor during the period 2018-1990 in coordinates 30 to 37.5 degrees north latitude and 45 to 52.5 degrees east longitude were obtained. GIS software was used to extract wind stress satellite data at Urmia, Tabriz, Zanjan, Hamadan, Sanandaj, Kermanshah, Khorramabad, Ardabil, Ilam and Ahvaz synoptic stations. To calculate wind stress, temperature, pressure and wind data were obtained from the Meteorological Organization. To evaluate satellite data and station data, the statistical criteria of correlation coefficient (CC), mean error (ME) Root Mean Square Error (RMSE) were used. The maximum (RMSE) is 0.060516 and the minimum is 0.000576. The correlation coefficient between observational and satellite data was calculated from 0.16 to 0.87. Wind stress trend analysis was calculated using non-parametric Mann-Kendall method. According to the results, the highest amount of wind stress in winter was observed in February in Ardabil station and the lowest in Kermanshah and Sanandaj stations. In spring, the highest wind stress was in Zanjan station in April and the lowest in Hamedan station in the same month. In summer, the highest amount of wind stress was observed in Ahvaz station in August and the lowest amount was observed in Sanandaj station in July. In autumn, the highest amount of stress was observed in Zanjan station in December and the lowest amount in Kermanshah station in the same month. Wind stress has a seasonal trend whose monthly changes are significant. There is a significant difference in the direction of wind stress flow due to the change of seasons.