The Impact of Mean State Errors on Equatorial Atlantic Interannual Variability in a Climate Model.

Ding, Hui, Keenlyside, Noel S., Latif, Mojib, Park, Wonsun and Wahl, Sebastian (2015) The Impact of Mean State Errors on Equatorial Atlantic Interannual Variability in a Climate Model. Open Access Journal of Geophysical Research - Oceans, 120 (2). pp. 1133-1151. DOI 10.1002/2014JC010384.

[img]
Preview
Text
jgrc21103.pdf - Published Version

Download (2502Kb) | Preview

Supplementary data:

Abstract

Observations show that the Equatorial Atlantic Zonal Mode (ZM) obeys similar physics to the El Niño Southern Oscillation (ENSO): positive Bjerknes and delayed negative feedbacks. This implies the ZM may be predictable on seasonal timescales, but models demonstrate little prediction skill in this region. In this study using different configurations of the Kiel Climate Model (KCM) exhibiting different levels of systematic error, we show that a reasonable simulation of the ZM depends on realistic representation of the mean state, i.e., surface easterlies along the equator, upward sloping thermocline to the east, with an equatorial SST cold tongue in the east. We further attribute the differences in interannual variability among the simulations to the individual components of the positive Bjerknes and delayed negative feedbacks. Differences in the seasonality of the variability are similarly related to the impact of seasonal biases on the Bjerknes feedback. Our results suggest that model physics must be enhanced to enable skillful seasonal predictions in the Tropical Atlantic Sector, although some improvement with regard to the simulation of Equatorial Atlantic interannual variability may be achieved by momentum flux correction. This pertains especially to the seasonal phase locking of interannual SST variability.

Document Type: Article
Funder compliance: info:eu-repo/grantAgreement/EC/FP7/603521
Additional Information: WOS:000352154800034
Keywords: mean state errors;Atlantic Nino;tropical Atlantic variability
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2014JC010384
ISSN: 0148-0227
Projects: RACE, SACUS, PREFACE, STEPS
Expeditions/Models/Experiments:
Date Deposited: 19 Jan 2015 10:11
Last Modified: 13 Apr 2017 08:43
URI: http://oceanrep.geomar.de/id/eprint/27005

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...