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利用一个全球海气耦合模式(BCM),结合观测资料,讨论了热带太平洋强迫对北大西洋年际气候变率的影响。研究表明,BCM能够相对合理地模拟赤道太平洋的年际变率模态及相应的海温距平型和大气遥相关型,尽管其准3年的振荡周期过于规则。来自数值模式和观测上的证据都表明,北大西洋冬季海温的主导性变率模态,即自北而南出现的“-+-”的海温距平型,受到来自热带太平洋强迫的显著影响,其正位相与赤道中东太平洋冷事件相对应。换言之,赤道太平洋暖事件的发生,在太平洋-北美沿岸激发出PNA遥相关型,进而通过在北大西洋产生类似NAO负位相的气压距平型,削弱本来与NAO正位相直接联系的三核型海温距平。北大西洋三核型海温距平对热带太平洋强迫的响应,要滞后2—3个月的时间。
Using a global coupled model of ocean-atmosphere (BCM) and observational data, the effects of tropical Pacific compaction on the interannual variability of the North Atlantic Ocean are discussed. The results show that BCM can relatively reasonably simulate the interannual variability modes of the equatorial Pacific and the corresponding SST anomalies and atmospheric teleconnections, although their quasi-3-year oscillation periods are too regular. Both numerical and observational evidence suggest that the predominant variability of the winter Atlantic SST in the North Atlantic, ie the “- + -” SST anomalies that occur from north to south, are strongly impacted by the tropical Pacific Impact, its positive phase corresponds with the equatorial central and eastern Pacific cold events. In other words, the occurrence of the equatorial Pacific warm event triggered a PNA teleconnection over the Pacific-North American coast and then weakened the trinocular-type sea that was directly linked to the NAO anomaly by generating an anomalous pressure anomaly similar to the NAO in the North Atlantic Temperature level. The response of the North Atlantic Trinocular SST to the forced tropical Pacific should lag 2-3 months.