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Title: Are Greenhouse Gases Changing ENSO Precursors in the Western North Pacific?

Using multiple observational and modeling datasets, we document a strengthening relationship between boreal winter sea surface temperature anomalies (SSTA) in the western North Pacific (WNP) and the development of the El Nino-Southern Oscillation (ENSO) one year later. The increased WNP-ENSO association emerged in the mid 20th century and has grown through the present, reaching correlation coefficients as high as ~0.70 in recent decades. Fully coupled climate experiments with the Community Earth System Model (CESM) replicate the WNP-ENSO association and indicate that greenhouse gases (GHG) are largely responsible for the observed increase. We speculate that shifts in the location and amplitudes of positive SST trends in the subtropical-tropical western Pacific impacts the low-level circulation so that WNP variability is increasingly influencing the development of ENSO one year later. A strengthened GHG-driven relationship between the WNP and ENSO provides an example of how anthropogenic climate change can potentially improve the skill of intraseasonal-to-interannual climate prediction.
Authors:
 [1] ; ;
  1. (Simon)
Publication Date:
OSTI Identifier:
1094946
Report Number(s):
PNNL-SA-88640
KP1703020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Climate, 26(17):6309-6322
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
global; warming; changing; ENSO; precursors; western; north pacific; ocean