Contribution of the Sea Surface Temperature over the Mediterranean-Black Sea to the Decadal Shift of the Summer North Atlantic Oscillation  

作　　者：孙建奇 袁薇 

机构地区：[1]Nansen-Zhu International Research Centre(NZC),Institute of Atmospheric Physics, Chinese Academy of Sciences [2]Climate Change Research Center(CCRC),Chinese Academy of Sciences [3]China Meteorological Administration Training Centre

出　　处：《Advances in Atmospheric Sciences》2009年第4期717-726,共10页大气科学进展（英文版）

基　　金：supported by National Basic Research Program of China(Grant No2009CB421406);the Chinese Academy of Sciences(Grant NosKZCX2-YW-Q1-02 and KZCX2-YW-BR-14);the National Natural Science Foundation of China(Grant Nos40631005 and 90711004)

摘　　要：Recent observational study has shown that the southern center of the summer North Atlantic Oscillation （SNAO） was located farther eastward after the late 1970s compared to before. In this study, the cause for this phenomenon is explored. The result shows that the eastward shift of the SNAO southern center after the late 1970s is related to the variability of the Mediterranean-Black Sea （MBS） SST. A warm MBS SST can heat and moisten its overlying atmosphere, consequently producing a negative sea level pressure （SLP） departure over the MBS region. Because the MBS SST is negatively correlated with the SNAO, the negative SLP departure can enhance the eastern part of the negative-phase of the SNAO southern center, consequently producing an eastward SNAO southern center shift. Similarly, a cold MBS SST produces an eastward positive-phase SNAO southern center shift. The reason for why the MBS SST has an impact on the SNAO after the late 1970s but why it is not the case beforehand is also discussed. It is found that this instable relationship is likely to be attributed to the change of the variability of the MBS SST on the decadal time-scale. In 1951 1975, the variability of the MBS SST is quite weak, but in 1978 2002, it becomes more active. The active SST can enhance the interaction between the sea and its overlying atmosphere, thus strengthening the connection between the MBS SST and the SNAO after the late 1970s. The above observational analysis results are further confirmed by sensitivity experiments.Recent observational study has shown that the southern center of the summer North Atlantic Oscillation （SNAO） was located farther eastward after the late 1970s compared to before. In this study, the cause for this phenomenon is explored. The result shows that the eastward shift of the SNAO southern center after the late 1970s is related to the variability of the Mediterranean-Black Sea （MBS） SST. A warm MBS SST can heat and moisten its overlying atmosphere, consequently producing a negative sea level pressure （SLP） departure over the MBS region. Because the MBS SST is negatively correlated with the SNAO, the negative SLP departure can enhance the eastern part of the negative-phase of the SNAO southern center, consequently producing an eastward SNAO southern center shift. Similarly, a cold MBS SST produces an eastward positive-phase SNAO southern center shift. The reason for why the MBS SST has an impact on the SNAO after the late 1970s but why it is not the case beforehand is also discussed. It is found that this instable relationship is likely to be attributed to the change of the variability of the MBS SST on the decadal time-scale. In 1951 1975, the variability of the MBS SST is quite weak, but in 1978 2002, it becomes more active. The active SST can enhance the interaction between the sea and its overlying atmosphere, thus strengthening the connection between the MBS SST and the SNAO after the late 1970s. The above observational analysis results are further confirmed by sensitivity experiments.

关 键 词：summer North Atlantic Oscillation Mediterranean-Black Sea sea surface temperature decadal variability 

分 类 号：P731.11[天文地球—海洋科学]