Monitoring of Climatic Factors Affecting on Dust & Sand Storm in Tehran Province

Abstract

In this study, according to the objectives and implementation method, climatic factors affecting ‎the dust phenomenon in active meteorological stations in Tehran province for a period of 30 years ‎were studied and analyzed. The results showed that in Mehrabad meteorological station, ‎temperature, humidity, rainfall, evaporation factors were directly related to DSI indices, wind ‎trend and dust storm changes, Lancaster, wind and storm diagrams, SPEI and the increase of ‎drought indices in the statistical period increased with temperature, evaporation and decrease. ‎Rainfall and humidity are proportional. DSI dust storm indexes were compared to 1 and ‎Lancaster drought index was compared to 50 and SPEI index was compared positively and ‎negatively in different years of the statistical period in the region and was classified in terms of ‎drought and wet season. The results of monthly and annual changes in wind trend and dust ‎storms showed that the region has no wind in all months and seasons with a speed of more than ‎‎20 meters per second. In terms of wind speed and frequency percentage, the highest wind speed ‎was related to late May and early June, and the lowest wind speed was related to late December ‎and early January. In addition, according to the changes in the wind trend and the documents of the ‎winds and thunderstorms, the prevailing wind direction in the region was from the west.‎