Decadal Variability of the Pacific Shallow Overturning Circulation and the Role of Local Wind Forcing

Abstract The Pacific shallow meridional overturning circulations, known as subtropical cells (STCs), link subduction in the regions to equatorial upwelling, suggesting possibility for winds influence sea surface temperatures (SSTs) by altering STCs’ strength. Indeed, STC variability provides basis one of mechanisms proposed explain origin tropical decadal (TPDV). While relationship between strength, measured their subsurface transport convergence, and SST variations is well documented, location wind forcing most influential on still being debated. In this study, we use output an ocean reanalysis examine Ocean changes during recent decades relate them forcing. Our results indicate that interior at each latitude largely controlled rather than induced remote variations. We also show establishment anomalous associated with westward propagation oceanic wind-forced Rossby waves, part adjustment process leads a zonal redistribution upper-ocean heat content both interannual time scales. These provide guidance understanding TPDV elucidating underlying dynamics can have practical implications monitoring Pacific. Significance Statement Slow temperature been shown affect global climate. study aims better these anomalies taking closer look upper circulation its Unlike previous studies, which related outside Pacific, here are primarily driven local winds. This result not only clarifies important, but suggests approach from observations.