Document Type : Original Article
Assistant Professor of Geography, Payame Noor University, Iran
PhD student in Meteorology, Islamic Azad University, Ahvaz Branch, Ahvaz, Iran.
The purpose of this study was to analyze the long-term mean of precipitation (P) and evapotranspiration (PET) based on climate drought in Aliabadektol, Gorgan, Bandar-e-Gaz, Bandar-e-Turkmen, Kalaleh, Gomishan, Minoodasht, Incheh-e-Borun, Gonbad-e-Kavous using Tavosi monthly drought indices. The rainfall of Ingot (K) and UNEP (UNEP) is used to detect changes in the period of 30 years. Also in this study, Hargreaves-Samani method was used to estimate the potential evapotranspiration. The U-U´ criterion was used to show the significance of the trend. U-U´ values were estimated for all months and whole years in Excel software environment. The study areas were divided into less than +1/96 or more than +1/96 or areas with trend using the Menkendal method. . After calculating the drought factor (AI) for the urban areas through Excel software, using the kriging distance method, the map of land area changes in the study area in the ArcGis software environment was drawn. For this purpose, to select the best interpolation method, the statistical indices of root mean square error RMS absolute value of MAE error were used. The results showed that the risk of drought and dust pollution in each study area is not far from expectation. In all studied cities, it seems that with decreasing and changing the trend of rainfall, the intensity of evapotranspiration increased by the same amount. The phenomenon of drought manifests itself far more. This phenomenon can affect the trend of agricultural products and reduce the amount of production and area under cultivation of products in Golestan province and reduce their yield.