西太平洋次表层海温异常与北赤道流异常海温西传

Sub-surface ocean temperature anomalies in the western Pacific and the anomalous ocean temperature westward transferring in the north equatorial current

通过对热带太平洋上层XBT温度资料分析 ,探讨了对厄尔尼诺 (ElNino)事件发生起重要作用的西太平洋暖池区次表层海温变暖异常的变化规律 ,揭示了影响西太平洋暖池区次表层海温变暖异常的形成机制。分析表明 :西太平洋暖池区的次表层海温异常变暖与赤道太平洋的北赤道流 ( 1 0°N)的海温异常存在密切关系。在ElNino事件发生的前期 ,位于赤道中东太平洋的异常暖水沿北赤道流温跃层潜沉向西太平洋暖池区输送 ,在西太平洋暖池堆积并向赤道西太平洋扩展 ,当异常暖水达到一定强度 ,并在大气的强迫下 ,异常暖水沿温跃层东传至赤道中东太平洋并上浮于海面 ,最终导致ElNino事件的爆发。北赤道流的异常海温西传是导致西太平洋暖池区次表层海温异常的重要机制 。

Based on XBT temperature data during 1955-1999 in the tropical Pacific, the regularity of the warm anomalous signals of the sub-surface ocean temperature in the warm pool region that play important role to the El Nino event occurred in the western Pacific has been analyzed and discussed.The formating mechanism of sub-surface ocean temperature anomaly in the warm pool region in the western Pacific has been announced. The analysis indicates that the relationship between the sub-surface anomalous warming in the western Pacific warm pool and the temperature anomalies in the northern equatorial current ( 10°N ) is close.In the earlier stage of the El Nino event, the anomalous warm water located in the equator central and eastern Pacific subducts toward the warm pool region of the western Pacific along thermocline of the northern equatorial current.Then piles up in the warm pool region and expands toward the equator western Pacific thoroughly. The eastward transport of warm water to the equator central and eastern Pacific will float to the sea surface along the sloping thermocline under the forcing of atmosphere.When anomalous warm water achieves a certain strength,it finally leads to the eruption of El Nino event.The westward transport of anomalous temperature in the northern equatorial current is right the important factor to trigger the sub-surface temperature anomalies in the warm pool region in the western Pacific.So it leads to the key interpreting that El Nino event occurs.