مخاطرات محیط طبیعی (Sep 2020)
Evaluation of Subtropical Jet Position Displacement on Iran and its Predictability Based on Two Climate Models including CanESM2 and GFDL-CM3
Abstract
Iran's location in the latitude of 25 to 40ºN in the northern hemisphere has made the subtropical jet stream a factor in regulating humidity systems in Iran, making it easy for humidity systems to enter the country when this jet stream is in Southern Iran. But as it moves northward, its strength decreases. In recent years, it has been reported that the positioning of subtropical jet streams in the Northern Hemisphere is shifting. Therefore, the purpose of this study is to evaluate the position of subtropical jet stream location and its variability over Iran. In this study, data on zoning wind velocity ranged between 30 and 80ºE in the Northern Hemisphere, at levels between 1000 and 10 hPa from NOAA, as well as outputs of circulation models including CanESM2 and GFDL-CM3 for the historical period 1948 to 2005 and periods Future from 2006 to 2100 were received from IPCC in two scenarios RCP4.5 and RCP8.5. In this study, the main components of the jet stream include the central core velocity of the jet stream and its latitude position. Investigation of the position and velocity of the jet stream indicates that the subtropical jet position changes in Iran and its eastern regions are followed by significant incremental changes. Whereas in west Iran, there is a significant decline in jet stream velocity changes. The future of Jet Stream positioning in Iran based on the CanESM2 and GFDL-CM3 climate models in both rcp4.5 and rcp8.5 scenarios indicates that relative to the base period in both scenarios as well as the near and far future of its position to the north Moves.
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