An Optimal Precursor of Northeast Pacific Marine Heatwaves and Central Pacific El Nino Events

The intensity of Northeast Pacific marine heatwaves (MHWs) has been related to local stochastic atmospheric forcing with limited predictability, but their evolution and persistence may be controlled by large-scale climate influences. A Linear Inverse Model containing both sea surface temperature and sea surface height (SSH) anomalies is used to identify the optimal conditions for observed Northeast Pacific MHW events that developed two-to-four seasons later. These optimal initial conditions include SSH anomalies that are responsible for most of the MHW growth, suggesting the relevance of subsurface ocean dynamics. Moreover, Northeast Pacific MHW growth occurs as part of a basin-scale dynamical mode that links the North Pacific to central equatorial Pacific El Nino events, whose subsequent development may lengthen MHW duration.

Automated summary

The intensity and persistence of Northeast Pacific marine heatwaves (MHWs) are influenced by both local atmospheric forcing and large-scale climate influences. Sea surface temperature and sea surface height anomalies play crucial roles in the development of MHWs, with subsurface ocean dynamics being relevant. The growth of Northeast Pacific MHWs is part of a basin-scale dynamical mode that connects the North Pacific with central equatorial Pacific El Nino events, potentially prolonging the duration of MHWs.