The Precipitation Changes on the Western and Eastern Aspects of Zagros Mountains

Zagros is one of the few Mountain ranges in western Asia. The amounts of precipitation are different in the eastern and western aspects of Zagros. The purpose of this study is to investigate the precipitation changes on the western and eastern aspects of the Zagros Mountains using orographic due to data from 1996-2017. The study area consists of 11 meteorological stations at an altitude of 232 to 1906 m. The results is represents that, that on the west aspects of Zagros there is an increasing trend in precipitation from 1200 to 1567 m. The amounts of precipitation are decreases to Mountain ridge. Towards the eastern slopes due to the decrease in humidity contents the precipitation is lesser than Western aspects.This study is show that the monthly precipitation averages on eastern aspects stations have been a decreasing trend has been decreasing at some of the locations since 2012-2017. According to this analysis, the precipitation on Western aspects has been increasing from Kouhdasht (379 mm) up to Alshtar (462mm) but then decreased gradually from Boroujerd (447mm) toward Kaboudarahang (300 mm) on Eastern aspects. precipitation changes on the Zagros aspects are related to the westerlies,moisture sources location and movement Paths of precipitation systems.