نوع مقاله : مقاله پژوهشی
نویسندگان
گروه جغرافیای طبیعی، دانشکده علوم جغرافیایی و برنامه ریزی، دانشگاه اصفهان، اصفهان، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Aim: Extreme rainfall fluctuations are one of Iran's environmental challenges. The spatial and temporal distribution of this amount also shows the uneven distribution of rainfall in the Iran.The heavy rains of 2019 and the relatively drought of 2018 and 2021 show the unevenness of rainfall.
Material & Method: To analyze this Iranian rainfall anomaly, the daily rainfall data of 360 weather stations in 1990-2021 and the synoptic indices of the winter seasons of 2019 and 2021, latitude N 10-90, and longitude E º 10-90 were used.
Finding: The findings showed that the probability of drought is 42%, drought is 35.5% and normal conditions are 22.5%. The results of the Markov chain show the highest probability of occurrence of normal drought to drought at 57% and consecutive drought at 46.2%. ANOVA showed that there is a significant difference between the climatic variables of wet and dry years. Observational conditions showed that in the sample year of wet year (2019), the operator of the Siberian high-pressure center had more pressure (1054 megabytes) in 2019 and 1032 mb in 2021. In the wet year, the frequency of cyclone and the temperature difference at the level of 500-1000 are higher, but the omega values are lower. These conditions are for the drought (2021), the amount of pressure in Siberia, the temperature difference between 500 and 1000 is less and Omega is more (stable air).
Conclusion: The results showed that the amount of rainfall in Iran fluctuates from year to year and the occurrence of low rainfall years is more than high rainfall.
Innovation: Therefore, planners should increase the risk of water supply and development and plan based on the minimum amount of precipitation. The physical capacity of the country's ecology should be reviewed and population concentration in limited areas should be avoided in order to reduce the vulnerability of the country's geographical environment.
کلیدواژهها [English]
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