摘要
The decadal variation of the intensity of the interannual opposite connection （seesaw） between the Somali and Australian cross-equatorial flows （CEFs） is investigated. During the period prior to the mid-1960s, and after the early-2000s, the intensity of the interannual seesaw connection is significantly weaker relative to the period between. Such interdecadal shifts in the interannual seesaw intensity bear a resemblance to the decadal shift in ENSO＇s strength, and can be further attributed to the phase transition of the Atlantic Multidecadal Oscillation （AMO）. When the AMO is in a positive phase, the ENSO amplitude reduces and the seesaw strength becomes weakened, and vice versa.The historical simulation outputs of the CMIP5 models are used to verify the connection, and a similar result was obtained. Thus, the notion that the intensity of the interannual opposite connection （seesaw） between the CEFs is modulated by the AMO is robust.
夏季索马里越赤道气流与澳大利亚越赤道气流之间存在翘翘板式的反向变化。本文利用NCEP/NCAR月平均再分析资料(1948–2013),分析了这种翘翘板式反向变化强度的年代际演变特征,并讨论了可能原因。结果表明:越赤道气流之间的反向变化强度在1966年左右和2002年左右分别发生了明显的转折。这种转折与其受ENSO强度的调制有关,在很大程度上可归于大西洋海温长周期年代际振荡(AMO)。因为AMO调制ENSO的强度,故而影响越赤道气流之间翘翘板式反向变化的强度。当AMO处于正(负)位相时,ENSO事件倾向于偏弱(偏强),越赤道气流之间翘翘板式反向变化关系变得相对较弱(较强)。它们三者间的关系在CMIP5历史试验(1860–2005)中依然存在。
基金
supported by the National Key Basic Research Program of China[grant number 973 Program,2015CB453202]
the National Natural Science Foundation of China[grant number 41375085],[grant number 41421004]
