Beaudin, E., E. Di Lorenzo, A. J. Miller, H. Seo and Y. Joh, 2023:
Impact of extratropical Northeast Pacific SST on U.S.
West Coast precipitation.
Geophysical Research Letters, 50, e2022GL102354.
Abstract.
The rainfall over the U.S. West Coast is known to be highly influenced by large-scale
atmospheric circulation and tropical climate teleconnections. However, the role of North
Pacific oceanic variability is less understood. Using high-resolution regional atmospheric
model simulations forced by sustained positive and negative phases of the extratropical
Pacific Decadal Oscillation sea surface temperature anomalies (SSTa), we diagnose the
precipitation changes over the U.S. West Coast during 2010-2020. We find that precipitation
anomalies are up to 60% stronger (weaker) for the warm (cold) cases, especially
over Northern and Central California during wintertime, and Baja California in the
summertime. In both seasons, precipitation is predominantly modulated through changes
in the water vapor flux, which are directed towards the coast in wintertime and away
from the coast during summertime. These flux anomalies are primarily driven by large-scale
changes in the wind associated with the atmospheric adjustment to the strong ocean
SSTa.
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