Poleward Expansion of jet stream in the Northern Hemisphere in Mid-Latitude

Document Type : Original Article


1 PhD student in Climatology, Zanjan university, Zanjan, Iran

2 Assistant Professor of Geogeraphy and Urban Planning Group of Kosar University Bojnourd, Iran

3 Department geography, Zanjan university Zanjan, Iran



In this study, the European Centre for Medium-Range Weather Forecasts (ECMWF) Version (ERA5) reanalysis forecast data with 0/25 * 0/25 spatial resolution and 40 years interval (1979-2018) from Vwind and Uwind using MATLAB, GrADS From programming in software in level 400-100hpa. Findings showed that the average vertical structure of jet stream subtropical northern hemisphere in summer is located in the northernmost latitude; And is observed from latitudes of 41 to 45 degrees north. In winter, it has shifted to the southernmost latitudes, and the subtropical core is more intense in winter than in other seasons. The seconds are observed at latitudes between 20 to 30 degrees north. This study polewaard that the jet stream of the northern hemisphere had two periods of increase during the years 1979 to 1997 in the amount of 1 to 2 degrees latitude also from 1999 to 2017 in the amount of 2 to 3 degrees latitude.


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