The Relationship Between EAP Wave Train And AO/NAO In The Northern Hemisphere In Summer And Its Impact On My Country's Continuous Precipitation

East Asia Pacific teleconnection pattern(EAP)is one of the most important teleconnection patterns affecting summer climate change in East Asia,which reflects the distribution of circulation systems in East Asia from low latitude to high latitude.The persistent anomalous precipitation is a kind of extreme climate event with strong destructiveness.The flood disaster caused by it has occurred frequently in our country in recent years,which has seriously affected the normal life of our people and made a huge threat to their lives.At the same time,social and economic development has suffered huge losses.Based on the NCEP/NCAR reanalysis data and precipitation data of China station,this paper studies the spatial and temporal characteristics of EAP teleconnection pattern in summer,and analyzes the anomaly of EAP teleconnection pattern and its influence on summer climate in China from the point of view of large-scale circulation.The relationship between the EAP type and the persistent anomalous precipitation in summer is mainly discussed.At the same time,The possible connection between the three modes is also revealed between the EAP type and the Arctic Oscillation(AO)and the North Atlantic Oscillation(NAO).The main conclusions are summarized as follows:(1)The EAP teleconnection in summer in the Northern Hemisphere is mainly quasi-3-year periodic variation,so the interdecadal variation is not obvious,mainly interannual.The spatial modes of the teleconnection type are reflected in all levels and heights,especially in the middle troposphere,and the center positions are very close,showing an obvious rather barotropic structure.There are obvious differences between high and low EAP index years in large scale circulation field.The distribution pattern in East Asia in high index year is basically "-+ +-",while that in low index year is just the opposite.The EAP teleconnection pattern has obvious relation to meteorological factors such as sea surface temperature,temperature and precipitation,which has further influence on the climate of China and the whole East Asia.(2)The correlation between EAP teleconnection type and AO and NAO is obvious,and the correlation between NAO and AO is greater than AO.By studying the different positive and negative correlation configurations of AO/NAO,it is found that the polar regions and the main ones are AO/NAO,which mainly reflects the state of AO/NAO when it is high or low.The high value is negative anomaly,but the low value is positive anomaly,but the middle and low latitude area is mainly EAP.At the high value,the East Asian region basically presents the "+-+" anomaly distribution,but the low value valueis "-+-" distribution situation.(3)The two types of anomalous precipitation processes occur mostly in the Yangtze River Basin and South China,and the frequency of occurrence in the northern part of China is relatively small,and the sustained precipitation duration and intensity of the Yangtze River Basin and South China are long and strong.Regional persistent torrential rain also occurs frequently in the central and southern regions of China.(4)By studying the circulation situation before and after the occurrence of two kinds of regional continuous torrential rain in the central and southern regions,it is found that the central subtropical high of the western Pacific Ocean is more westward than the southern region,and the upper jet region is more easterly.The position of the east ridge of the South Asia High is also relatively easterly,and the general circulation situation is inclined to the circulation situation of the low EAP index year.On the contrary,the southern region is inclined to the circulation situation of EAP high index year.