Capotondi, A., P. D. Sardeshmukh, E. Di Lorenzo,
A. Subramanian and A. J. Miller, 2019:
Predictability of US West Coast Ocean Temperatures is not solely due to ENSO
Scientific Reports, 9, 10993.
Abstract.
The causes of the extreme and persistent warming in the Northeast Pacific from the winter of
2013/14 to that of 2014/15 are still not fully understood. While global warming may have
contributed, natural influences may also have played a role. El Nino events are often implicated in
anomalously warm conditions along the US West Coast (USWC). However, the tropical Pacific
sea surface temperature (SST) anomalies were generally weak during 2014, calling into question
their role in the USWC warming. In this study, we identify tropical Pacific “sensitivity patterns”
that optimally force USWC warming at a later time. We find that such sensitivity patterns do not
coincide with the mature SST anomaly patterns usually associated with ENSO, but also include
elements associated with ENSO SST precursors and SST anomalies in the central/western
equatorial Pacific. El Nino events that produce large USWC warming, irrespective of their
magnitude, do project on the sensitivity pattern and are characterized by a distinct evolution of the
North Pacific atmospheric and oceanic fields. However, even weak tropical SST anomalies in the
right location, and not necessarily associated with ENSO, can significantly influence USWC
conditions and enhance their predictability.
Reprint (pdf)