Enhancement of the Summer North Atlantic Oscillation Influence on Northern Hemisphere Air Temperature  

作　　者：袁薇 孙建奇 

机构地区：[1]China Meteorological Administration Training Centre [2]Institute of Atmospheric Physics,Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2009年第6期1209-1214,共6页大气科学进展（英文版）

基　　金：supported by Chinese Academy of Sciences(Grant Nos.KZCX2-YW-Q1-02 and KZCX2-YW-217);the National Natural Science Foundation of China(Grant Nos.40905041,40631005,and 90711004);the IAP innovation program(Grant No.IAP07412)

摘　　要：This study investigates the relationship between the summer North Atlantic Oscillation （SNAO） and the simultaneous Northern Hemisphere （NH） land surface air temperature （SAT） by using the Climate Research Unit （CRU） data. The results show that the SNAO is related to NH land SAT, but this linkage has varied on decadal timescales over the last 52 years, with a strong connection appearing after the late 1970s, but a weak connection before. The mechanism governing the relationship between the SNAO and NH land SAT is discussed based on the NCEP/NCAR reanalysis data. The results indicate that such a variable relationship may result from changes of the SNAO mode around the late 1970s. The SNAO pattern was centered mainly over the North Atlantic before the late 1970s, and thus had a weak influence on the NH land SAT. But after the late 1970s, the SNAO pattern shifted eastward and its southern center was enhanced in magnitude and extent, which transported the SNAO signal to the North Atlantic surrounding continents and even to central East Asia via an upper level wave train along the Asian jet.This study investigates the relationship between the summer North Atlantic Oscillation （SNAO） and the simultaneous Northern Hemisphere （NH） land surface air temperature （SAT） by using the Climate Research Unit （CRU） data. The results show that the SNAO is related to NH land SAT, but this linkage has varied on decadal timescales over the last 52 years, with a strong connection appearing after the late 1970s, but a weak connection before. The mechanism governing the relationship between the SNAO and NH land SAT is discussed based on the NCEP/NCAR reanalysis data. The results indicate that such a variable relationship may result from changes of the SNAO mode around the late 1970s. The SNAO pattern was centered mainly over the North Atlantic before the late 1970s, and thus had a weak influence on the NH land SAT. But after the late 1970s, the SNAO pattern shifted eastward and its southern center was enhanced in magnitude and extent, which transported the SNAO signal to the North Atlantic surrounding continents and even to central East Asia via an upper level wave train along the Asian jet.

关 键 词：Summer North Atlantic Oscillation surface air temperature wave train 

分 类 号：P461[天文地球—大气科学及气象学]