The origins of the anomalous warming in the C alifornia coastal ocean and S an F rancisco B ay during 2014–2016 Journal of Geophysical Research: Oceans

During 2014 exceptionally warm water temperatures developed across a wide area off the Cali- fornia coast and within San Francisco Bay (SFB) and persisted into 2016. Observations and numerical model output are used to document this warming and determine its origins. The coastal warming was mostly con-fined to the upper 100 m of the ocean and was manifested strongly in the two leading modes of upper ocean (0–100 m) temperature variability in the extratropical eastern Pacific. Observations suggest that the coastal warming in 2014 propagated into nearshore regions from the west while later indicating a warminginfluence that propagated from south to north into the region associated with the 2015–2016 El Ni ~no event. An analysis of the upper ocean (0–100 m) heat budget in a Regional Ocean Modeling System (ROMS) simu- lation confirmed this scenario. The results from a set of sensitivity runs with the model in which the lateralboundary conditions varied supported the conclusions drawn from the heat budget analysis. Concerning