Decadal changes in the basin-wide heat budget of the mid-latitude North Pacific Ocean

Abstract Research has indicated that the meridional heat transport (MHT) in North Pacific Ocean (NP) across 24°N increased 1980s and 1990s, resulting different distributions: ocean content (OHC) 1980s, while net surface release was strengthened 1990s; however, reasons for these differences remained unclear. The authors revisited investigation of budget NP mainly using hydrographic observations to understand why distribution between 2 decades extend analysis 2010s. OHC upper 700 m north east 137°E exhibited sharp increases around 1990 as well 2010s, it nearly stable between. northward retreat subarctic gyre boundary coincided with spin-up subtropical late thereby allowing warm anomaly from subtropics propagate northeastward. Meanwhile, concurrent weakening wintertime westerlies resulted suppression loss western NP. In contrast, southward shift front suppressed rise, despite MHT increase 1990s. unprecedented warming occurred eastern estimation based on indicates must have been since did not increase; latest atmospheric reanalysis datasets failed reproduce this.