Monthly mean sea level variations computed using a linear, reduced-gravity, multi-mode model are combined with satellite measurements to explore why Central Pacific (CP) ENSO events occur more frequently since 2000s. The pivot point for sea level (and hence thermocline) variations has shifted westward in response to an increase in zonal wind stress variance in the western equatorial Pacific. As a result, the Nino4 region is increasingly to the east of the pivot point enabling the thermocline feedback to operate there, strengthening the Bjerknes feedback mechanism in the Nino4 region and leading to an increase in the occurrence of CP events. The increased variance of wind stress in the western Pacific is, in turn, caused by the resulting increase in the frequency of CP events. These arguments imply a positive feedback in which CP events are self-maintaining and suggest that they may be part of the natural variability of the climate system and could occur without the need for changes in external forcing.

使用线性，减少重力的多模式模型计算的月平均海平面变化与卫星测量结果相结合，以探讨为什么自2000年代以来中太平洋（CP）ENSO事件发生的频率更高。响应赤道西太平洋纬向风应力变化的增加，海平面（以及因此的温跃层）变化的枢轴点已向西移动。结果，Nino4区域越来越多地位于枢轴点以东，从而使热跃线反馈能够在那里运行，从而增强了Nino4区域中的Bjerknes反馈机制，并导致了CP事件的发生。反过来，西太平洋风应力变化的增加是由CP事件发生频率的增加引起的。