Document Type : Research Paper
Authors
1 Professor, Department of Geography, Faculty of Humanities, University of Zanjan, Zanjan, Iran
2 M.Sc., Department of Physical Geography, Faculty of Humanities, University of Zanjan, Zanjan, Iran
Abstract
The specific nature of heavy precipitation and its consequences have caused the phenomenon of particular importance in environmental planning and management of water. analysis Synoptic conditions of atmospheric circulation patterns and identifying factors affecting the occurrence of heavy precipitation are very important. In this study, to analyze the effect of low-pressure cut blocking system on the precipitation during 8 -13 March 2010, the weather maps of mean sea level pressure, geopotential height at 500 and 850 hPa level, wind components, moisture flux convergence and Omega indicators were analyzed. Using synoptic maps, position and movement of weather systems such as troughs and ridges, wind field, and high-pressure and low-pressure systems near the ground level were evaluated. The data of daily precipitation and hourly flow rate were analyzed for 29 meteorological stations and hydrometery within and outside the basin. The results suggest the establishment of Scut-off low in the East Mediterranean and its associated trough displacement and ground accompaniment during 8-13 March, which have provided the conditions for the creation of heavy rainfall. Wind field in atmospheric levels, especially at 850 hPa level, have an important role in humidity feeding of atmospheric systems. The negative values of Omega also resulted in the promotion of air aerodynamics in the atmospheric levels and strengthening of convective flows has led to precipitation.
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