skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Ocean wave dynamics and El Nino

Abstract

The response of an ocean general circulation model to specified wind stress is used to understand the role of ocean wave propagation in the evolution of El Nino events in sea surface temperatures (SST) in the equatorial Pacific Ocean. In a control experiment the ocean model reproduces observed equatorial Pacific interannual variability in response to forcing by the observed wind stress. The ocean model is then forced with the same wind stress but with the time evolution of the wind stress forcing reversed. An analysis of the anomalies from the annual cycle in these two experiments delineates the parts of the response that are in equilibrium with and out of equilibrium with the wind stress forcing. The experiment demonstrates that the heat content is not in equilibrium with the wind stress forcing either on or near the equator. Very close to the equator the slope of the thermocline is in equilibrium with the wind stress, but the mean heat content is far from equilibrium. Slightly off of the equator in the western Pacific westward propagating heat content anomalies appear to originate in regions of strong wind stress forcing and then propagate to the western boundary. These westward propagating anomalies alsomore » depart significantly from equilibrium with the wind stress forcing. Additional experiments allow these westward propagating anomalies to be identified as freely propagating Rossby waves. The Rossby waves are shown to determine the equatorial heat content response to the wind stress forcing when they arrive at the western boundary and to be responsible for the nonequilibrium behavior of the equatorial mean heat content. A simplified coupled model is derived by fitting the results and estimating parameter values from the numerical experiments. 45 refs., 16 figs.« less

Authors:
; ;  [1]
  1. Center for Ocean-Land-Atmosphere, Calverton, MD (United States)
Publication Date:
OSTI Identifier:
171724
Resource Type:
Journal Article
Journal Name:
Journal of Climate
Additional Journal Information:
Journal Volume: 8; Journal Issue: 10; Other Information: PBD: Oct 1995
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; WIND; WAVE PROPAGATION; FORCING FUNCTIONS; OCEANIC CIRCULATION; DYNAMICS; GENERAL CIRCULATION MODELS; PACIFIC OCEAN; TIME DELAY; SOUTHERN OSCILLATION

Citation Formats

Schneider, E K, Huang, B, and Shukla, J. Ocean wave dynamics and El Nino. United States: N. p., 1995. Web. doi:10.1175/1520-0442(1995)008<2415:OWDAEN>2.0.CO;2.
Schneider, E K, Huang, B, & Shukla, J. Ocean wave dynamics and El Nino. United States. https://doi.org/10.1175/1520-0442(1995)008<2415:OWDAEN>2.0.CO;2
Schneider, E K, Huang, B, and Shukla, J. 1995. "Ocean wave dynamics and El Nino". United States. https://doi.org/10.1175/1520-0442(1995)008<2415:OWDAEN>2.0.CO;2.
@article{osti_171724,
title = {Ocean wave dynamics and El Nino},
author = {Schneider, E K and Huang, B and Shukla, J},
abstractNote = {The response of an ocean general circulation model to specified wind stress is used to understand the role of ocean wave propagation in the evolution of El Nino events in sea surface temperatures (SST) in the equatorial Pacific Ocean. In a control experiment the ocean model reproduces observed equatorial Pacific interannual variability in response to forcing by the observed wind stress. The ocean model is then forced with the same wind stress but with the time evolution of the wind stress forcing reversed. An analysis of the anomalies from the annual cycle in these two experiments delineates the parts of the response that are in equilibrium with and out of equilibrium with the wind stress forcing. The experiment demonstrates that the heat content is not in equilibrium with the wind stress forcing either on or near the equator. Very close to the equator the slope of the thermocline is in equilibrium with the wind stress, but the mean heat content is far from equilibrium. Slightly off of the equator in the western Pacific westward propagating heat content anomalies appear to originate in regions of strong wind stress forcing and then propagate to the western boundary. These westward propagating anomalies also depart significantly from equilibrium with the wind stress forcing. Additional experiments allow these westward propagating anomalies to be identified as freely propagating Rossby waves. The Rossby waves are shown to determine the equatorial heat content response to the wind stress forcing when they arrive at the western boundary and to be responsible for the nonequilibrium behavior of the equatorial mean heat content. A simplified coupled model is derived by fitting the results and estimating parameter values from the numerical experiments. 45 refs., 16 figs.},
doi = {10.1175/1520-0442(1995)008<2415:OWDAEN>2.0.CO;2},
url = {https://www.osti.gov/biblio/171724}, journal = {Journal of Climate},
number = 10,
volume = 8,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 1995},
month = {Sun Oct 01 00:00:00 EDT 1995}
}