The relationship between the Arctic Oscillation and ENSO as simulated by CCSM4

The correlation between the Arctic Oscillation （AO） and ENSO reflects the strength of the interaction between climate systems in the low and high latitudes. Based on the long-term （501 years） control simulation of CCSM4, the authors investigated the linkage between the AO and ENSO in boreal winter. Based on the correlation coefficients between them, the authors divided the entire period into two groups： one that included the years with statistically significant correlations （G1）, and the other the years with insignificant correlations （G2）. in G1, the AO-related atmospheric circulation pattern resembles the ENSO-related one. The Aleutian Low （AL） acts as a bridge linking these two modes, in G2, however, the AO and ENSO signals are confined to the mid-high and mid-low latitudes, respectively. There is no significant linkage between the AO and ENSO in boreal winter, showing a low correlation coefficient. Further analysis suggests that changes in the climatological features, including the strengthened AO, the negative Pacific Decadal Oscillation phase, and the weakened AL, may be responsible for the enhanced relationships.

北极涛动(AO)和ENSO可以显著影响我国冬季气候。我们基于CCSM4的长期(501年)参照试验结果,揭示了冬季AO和ENSO间的关系存在年代际变化。在二者相关显著时期,二者对我国南、北气温均有显著影响;而在相关不显著时期,二者分别主要影响我国北部和南部的气温。气候态上出现的正位相AO、负位相太平洋年代际振荡和减弱的阿留申低压,可能有利于高低纬之间异常信号的传播,导致AO和ENSO的联系显著。