The Impact Of The Shift Of The Arctic Stratospheric Polar Vortex On The Arctic Oscillation In The Troposphere

This paper uses three kinds of reanalysis data(ERA-Interim?NCEP/NCAR and JRA-55)to analyze the relationship between the polar vortex position in the Arctic stratosphere and Arctic Oscillation(AO)in the troposphere in winter from the synoptic scale and interdecadal time scale.The influence of stratospheric pole vortex position on the intensity,duration and spatial pattern of AO in troposphere is analyzed,and the mechanism of abnormal signal of stratospheric pole vortex position affecting AO in troposphere is discussed.The main conclusions are as follows:1.When the stratospheric polar vortex shifts,the frequency of the AO negative phase in the troposphere is higher,and the frequency of the AO positive phase is lower.In other words,the stratospheric polar vortex shift favors the occurance of AO negative phase in the troposphere.2.The stratospheric polar vortex shift enhances the overall intensity of AO events,and the duration of AO events is significantly enhanced.3.Comparing the two kinds of AO events,the intensity of the three action centers during the shift of the stratospheric polar vortex is stronger than that during the non-shift of the stratospheric polar vortex.4.During the AO-shift event,there is a significant westward movement of the Arctic action center,in which the average location of the Arctic action center from day 0 to day 3 is located in the north of the Chukchi Sea.Furthermore,the relationship between the polar vortex position and the AO in the Arctic stratosphere is analyzed at the interdecadal time scale.The study found that:1.During the 1960 s and 1970 s,the intensity of the Arctic Oscillation Center in the North Pacific was weak,and after the 1980 s,the North Pacific action center was strong,and the action center showed obvious interdecadal changes.2.The stratospheric polar vortex position may be the reason of significant inter-decadal changes in the North Pacific action center.The shift of the stratospheric polar vortex causes the eastern Pacific wave train intensity in the troposphere to increase significantly,and then causes the intensity of the North Pacific action center of the AO pattern to increase significantly.Moreover,using the simulation results of 12 CMIP5 coupling models,the paper analyzed the possible trends of RCP4.5 intensity of the Arctic Oscillation and the intensity of the two action centers in the future and finds that:1.The AO index showed an obvious downward trend in 2006-2035,and the AO index showed a significant upward trend in 2070-2100.During the whole time period.2.Between 2006 and 2100,the intensity of the North Pacific and North Atlantic action centres in Arctic waves showed a significant upward trend.Among the 12CMIP5 coupling modes,the variation of the North Pacific action center is higher than that of the North Atlantic action center.By studying the impact of the stratospheric polar vortex shift on the Arctic Oscillation,this paper helps to further improve the understanding of the interaction between the stratosphere and the troposphere,and to improve the accuracy of the prediction of the extension period in the troposphere and the short-term climate prediction.