Investigation on dynamical structure and moisture sources of heavy precipitation in south and south-west of Iran

Autor: Zainab Mohammadi, Mahnaz Jafari, Hassan Lashkari
Rok vydání: 2020
Předmět:
Zdroj: Arabian Journal of Geosciences. 13
ISSN: 1866-7538
1866-7511
DOI: 10.1007/s12517-020-06097-w
Popis: The purpose of this research is to study the structure and mechanism of heavy precipitation systems on the Arabian Peninsula and Iran and what is role of hot seas on providing moisture to these systems. To this end, precipitation data from 45 stations in the region during the period 1982–2017 were extracted. Based on local indices, the rainfall threshold of 30 mm was selected as the heavy rainfall criterion. By this criterion, 92 single-day systems with heavy rainfall were identified. By visual inspection of different atmospheric levels maps, one sample that comprised more than 80% of the samples were selected as the dominant model. The vertical structure and the moisture flux of this pattern were plotted in three boxes (system motion path). The results of this study showed that high humidity systems are supplied from three regions. In the first box (Sudan), the highest moisture advection in the lower troposphere comes from Intertropical Convergence Zone (ITCZ), the Indian Ocean, and the Arabian Sea; at second box comes from the Red Sea, Arab, and Oman; and the at third box comes from the Persian Gulf. The new finding of this research is the identification of a front line. This front line is caused by cold advection of polar side latitudes by a deep trough in the eastern Mediterranean and warm and humid advection of the southern warm seas, while so far it is thought that convection phenomenon to be the main cause of heavy rainfall and flooding in this region.
Databáze: OpenAIRE
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