Investigation of the role of Stratosphere - Troposphere cover of Polar Vortex in the occurrence of heavy and widespread rainfall in Iran

10.22034/jmas.2022.342246.1173
Volume 4, Issue 2 - Serial Number 2
Summer 2021
Pages 147-160

Document Type : Original Article

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Abstract
In recent decades, new theories have emerged to identify the interaction between the Stratosphere and Troposphere currents. In this regard, an attempt was made to investigate the role of Stratosphere and Troposphere coercions of Polar Vortex in relation to heavy and pervasive rainfall in Iran. For this purpose, GPM Gridded data were used for the spatial pattern of precipitation and data from the National Center for Environmental Prediction / Atmospheric Science (NCEP / NCAR) and the European Center Medium-Range Weather Forecasting (ECMWF). The results showed that the rotation of the Stratosphere cover of the Polar Vortex basin has entered the upper Troposphere by deforming to an elliptical shape and by deepening the central core of the polar pan, the potential Vorticity and the anomaly of the geopotential height of the Lower Stratosphere cover. With the increase of potential Vorticity and flux from its maximum center from the northeast of Russia to the region, it has caused Tropopuse folding and finally the decrease of geopotential over the Middle East. The formation of anomalies in periods with heavy and widespread rainfall in Iran can be predicted between 18 to 20 days before the occurrence of this event in the middle and upper spheres. On the other hand, the change of Tropopuse pressure in the Arctic and Middle East region showed that by increasing the pressure in the polar Tropopuse with a delay of 2 to 3 days on days with heavy rainfall, it reduces the height of the Troposphere geopotential.

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