The variability of subsurface ocean in the tropical Pacific was analyzed based on the simple ocean data assimilation (SODA) dataset. The results indicate that the path of anomalous temperature signal transmitting to the western Pacific in an ENSO cycle has close relationship with the depth distribution of thennocline. The climatological thermocline was very shallow along 1()°N. Therefore, the thennocline was like a ridge through the eastern to western Pacific under the sea surface. As a result, the anomalous ENSO signal coming from the equator could not get across this area to the north, so the signal in the eastern Pacific could only transmit to the western Pacific along this region. On the contrary, the thennocline in the southern Pacific does not have such a character and could not block the signal's propagation from the equator to higher latitude. Further research indicates that the signal intensity of temperature anomaly changes in the ENSO cycle, especially when the signal is transmitted from the eastern Pacific to the western Pacific along KPN. Except for the temperature anomaly from 10°N in the eastern Pacific, the temperature anomaly that ultimately approaches the western Pacific warm pool was also affected by the local surface wind in the North Pacific and the temperature anomaly from higher latitude.%利用SODA等资料分析了热带太平洋次表层海洋要素的变化特征,结果表明,ENSO循环过程中次表层异常海温信号在赤道外向西传播的路径与温跃层深度的分布有一定关系,10°N附近是气候平均温跃层深度的极小值区域,温跃层在该区域形成了一个从东到西的阻隔带,阻挡了来自赤道地区的ENSO信号继续向北传播,从而转向西传播；而南半球温跃层深度的气候分布不具备这一特征,不利于ENSO信号在南半球的向西传播.进一步的研究还表明,ENSO信号在整个循环过程中,异常海温的主周期是变化的,特别是在沿10°N附近向西传播的过程中,ENSO信号的主周期变化较大.推断西太平洋暖池区域的ENSO信号除了在循环过程中自东太平洋10°N传来的以外,还受其他因素的影响,例如局地的大气变化引起的海温异常,以及来自中高纬度的异常海温信号等因素.
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