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Title: Interdecadal variability of the Pacific Ocean: Model response to observed heat flux and wind stress anomalies

Abstract

Variability of the Pacific Ocean is examined in numerical simulations with an ocean general circulation model forced by observed anomalies of surface heat flux, wind stress and turbulent kinetic energy TKE over the period 1970-88. The model captures the 1976-1977 winter time climate shift in sea surface temperature, as well as its monthly, seasonal and longer term variability as evidenced in regional time series and empirical orthogonal function analyses. Examination of the surface mixed-layer heat budget reveals that the 1976-77 shift was caused by a unique concurrance of sustained heat flux input anomalies and very strong horizontal advection anomalies during a multi-month period preceding the shift in both the central Pacific region (where cooling occurred) and the California coastal region (where warming occurred). In the central Pacific, the warm conditions preceding and the cold conditions following the shift tend to be maintained by anomalous vertical mixing due to increases in the atmospheric momentum flux (TKE input) into the mixed layer (which deepens in the model after the shift) from the early 1970s to the late 1970s and 1980s. Since the ocean model does not contain feedback to the atmosphere and its succeeds in captureing the major feature of the 1976-77more » shift, it appears that the midlatitude part of the shift was driven by the atmosphere, although effects of midlatitude ocean-atmosphere feedback are still possible. The surface mixed-layer heat budget also reveals that, in the central Pacific, the effects of heat flux input and vertical mixing anomalies are comparable in amplitude while horizontal advection anomalies are roughly half that size. In the California coastal region, in contrast, where wind variability is much weaker than in the central Pacific, horizontal advection and vertical mixing effects on the mixed layer heat budget are only one-quarter the size of typical heat flux input anomalies. 62 refs., 13 figs.« less

Authors:
; ;  [1]
  1. Scripps Institution of Oceanography, La Jolla, CA (United States) [and others
Publication Date:
OSTI Identifier:
241225
Resource Type:
Journal Article
Journal Name:
Climate Dynamics
Additional Journal Information:
Journal Volume: 9; Journal Issue: 6; Other Information: PBD: Mar 1994
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; PACIFIC OCEAN; ANNUAL VARIATIONS; GENERAL CIRCULATION MODELS; HEAT FLUX; WIND

Citation Formats

Miller, A.J., Cayan, D.R., and Barnett, T.P.. Interdecadal variability of the Pacific Ocean: Model response to observed heat flux and wind stress anomalies. United States: N. p., 1994. Web. doi:10.1007/s003820050026.
Miller, A.J., Cayan, D.R., & Barnett, T.P.. Interdecadal variability of the Pacific Ocean: Model response to observed heat flux and wind stress anomalies. United States. doi:10.1007/s003820050026.
Miller, A.J., Cayan, D.R., and Barnett, T.P.. Tue . "Interdecadal variability of the Pacific Ocean: Model response to observed heat flux and wind stress anomalies". United States. doi:10.1007/s003820050026.
@article{osti_241225,
title = {Interdecadal variability of the Pacific Ocean: Model response to observed heat flux and wind stress anomalies},
author = {Miller, A.J. and Cayan, D.R. and Barnett, T.P.},
abstractNote = {Variability of the Pacific Ocean is examined in numerical simulations with an ocean general circulation model forced by observed anomalies of surface heat flux, wind stress and turbulent kinetic energy TKE over the period 1970-88. The model captures the 1976-1977 winter time climate shift in sea surface temperature, as well as its monthly, seasonal and longer term variability as evidenced in regional time series and empirical orthogonal function analyses. Examination of the surface mixed-layer heat budget reveals that the 1976-77 shift was caused by a unique concurrance of sustained heat flux input anomalies and very strong horizontal advection anomalies during a multi-month period preceding the shift in both the central Pacific region (where cooling occurred) and the California coastal region (where warming occurred). In the central Pacific, the warm conditions preceding and the cold conditions following the shift tend to be maintained by anomalous vertical mixing due to increases in the atmospheric momentum flux (TKE input) into the mixed layer (which deepens in the model after the shift) from the early 1970s to the late 1970s and 1980s. Since the ocean model does not contain feedback to the atmosphere and its succeeds in captureing the major feature of the 1976-77 shift, it appears that the midlatitude part of the shift was driven by the atmosphere, although effects of midlatitude ocean-atmosphere feedback are still possible. The surface mixed-layer heat budget also reveals that, in the central Pacific, the effects of heat flux input and vertical mixing anomalies are comparable in amplitude while horizontal advection anomalies are roughly half that size. In the California coastal region, in contrast, where wind variability is much weaker than in the central Pacific, horizontal advection and vertical mixing effects on the mixed layer heat budget are only one-quarter the size of typical heat flux input anomalies. 62 refs., 13 figs.},
doi = {10.1007/s003820050026},
journal = {Climate Dynamics},
number = 6,
volume = 9,
place = {United States},
year = {1994},
month = {3}
}