Details:

Journal Title:
Journal of Climate
Personal Author:
Wu, Xian ; Okumura, Yuko M. ; DiNezio, Pedro N. ; Yeager, Stephen G. ; Deser, Clara
Wu, Xian ; Okumura, Yuko M. ; DiNezio, Pedro N. ; Yeager, Stephen G. ; Deser, Clara Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research)
Description:
The mean-state bias and the associated forecast errors of the El Niño–Southern Oscillation (ENSO) are investigated in a suite of 2-yr-lead retrospective forecasts conducted with the Community Earth System Model, version 1, for 1954–2015. The equatorial Pacific cold tongue in the forecasts is too strong and extends excessively westward due to a combination of the model’s inherent climatological bias, initialization imbalance, and errors in initial ocean data. The forecasts show a stronger cold tongue bias in the first year than that inherent to the model due to the imbalance between initial subsurface oceanic states and model dynamics. The cold tongue bias affects not only the pattern and amplitude but also the duration of ENSO in the forecasts by altering ocean–atmosphere feedbacks. The predicted sea surface temperature anomalies related to ENSO extend to the far western equatorial Pacific during boreal summer when the cold tongue bias is strong, and the predicted ENSO anomalies are too weak in the central-eastern equatorial Pacific. The forecast errors of pattern and amplitude subsequently lead to errors in ENSO phase transition by affecting the amplitude of the negative thermocline feedback in the equatorial Pacific and tropical interbasin adjustments during the mature phase of ENSO. These ENSO forecast errors further degrade the predictions of wintertime atmospheric teleconnections, land surface air temperature, and rainfall anomalies over the Northern Hemisphere. These mean-state and ENSO forecast biases are more pronounced in forecasts initialized in boreal spring–summer than other seasons due to the seasonal intensification of the Bjerknes feedback.
Keywords:
[+]
Atmospheric Science
Source:
Journal of Climate, 35(11), 3261-3277
DOI:
https://doi.org/10.1175/jcli-d-21-0470.1
ISSN:
0894-8755;1520-0442;
Format:
PDF
Publisher:
American Meteorological Society
Document Type:
Journal Article
Funding:
Grant no. NA17OAR4310145 ; Grant no. NA17OAR4310149
Grant no. NA17OAR4310145 ; Grant no. NA17OAR4310149 Less -
Rights Information:
Other
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:355d330097860b32388144970c290c3dc1585c2782bf61873616eef8dad86f5f
Download URL:
https://repository.library.noaa.gov/view/noaa/60427/noaa_60427_DS1.pdf
File Type:

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