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Modal structure of variations in the tropical climate system. Pt. 1. Observations

Miscellaneous:

Abstract

We have investigated the modal structure of climate variability in the tropical Pacific by analyzing zonal surface wind stress, sea surface temperature, and upper ocean heat content during the period 1967 to 1986. Three principal climate modes could be indentified: The annual cycle, a quasi-biennial (QB) mode, and a low-frequency (LF) mode with a time scale of about 3 years. The annual cycle is mostly governed by the movement of the sun, local air-sea heat exchange and mixing processes. In the eastern equatorial Pacific, the annual cycle involves a westward propagating coupled mode which is caused by processes within the surface mixed layer. The quasi-biennial mode near the equator shows aspects of both mixed layer physics and shallow water wave dynamics and is therefore best described as a `mixed surface/subsurface dynamics` mode. Poleward of 10 degrees local air-sea heat exchange and mixing processes become also important. The low-frequency mode is the traditional ENSO mode, which is best described as the oceanic response to low-frequency atmospheric forcing. Equatorial wave dynamics is crucial for the low-frequency mode. The quasi-biennial mode shows some evidence for a phase-locking to the annual cycle. However, the period of the quasi-biennial mode is not steady, ranging from  More>>
Authors:
Latif, M; [1]  Barnett, T P; [2]  Mizuno, K [3] 
  1. Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)
  2. Climate Research Div., Cripps Institution of Oceanography, La Jolla, CA (United States)
  3. Far Sea Fisheries Research Lab., Shimizu (Japan)
Publication Date:
Sep 01, 1992
Product Type:
Miscellaneous
Report Number:
ETDE-mf-93744925
Reference Number:
SCA: 540100; PA: DE-92:016668; SN: 93000906398
Resource Relation:
Journal Issue: no. 91; Other Information: PBD: Sep 1992; Related Information: Max-Planck-Institut fuer Meteorologie. Report
Subject:
54 ENVIRONMENTAL SCIENCES; PACIFIC OCEAN; TROPICAL REGIONS; CLIMATES; ANNUAL VARIATIONS; AIR-WATER INTERACTIONS; SOUTHERN OSCILLATION; TIME-SERIES ANALYSIS; 540100; ENVIRONMENTAL SCIENCES, ATMOSPHERIC
OSTI ID:
10106599
Research Organizations:
Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Other: ON: DE93744925; TRN: DE9216668
Availability:
OSTI; NTIS (US Sales Only)
Submitting Site:
DE
Size:
28 p.
Announcement Date:
Jun 30, 2005

Miscellaneous:

Citation Formats

Latif, M, Barnett, T P, and Mizuno, K. Modal structure of variations in the tropical climate system. Pt. 1. Observations. Germany: N. p., 1992. Web.
Latif, M, Barnett, T P, & Mizuno, K. Modal structure of variations in the tropical climate system. Pt. 1. Observations. Germany.
Latif, M, Barnett, T P, and Mizuno, K. 1992. "Modal structure of variations in the tropical climate system. Pt. 1. Observations." Germany.
@misc{etde_10106599,
title = {Modal structure of variations in the tropical climate system. Pt. 1. Observations}
author = {Latif, M, Barnett, T P, and Mizuno, K}
abstractNote = {We have investigated the modal structure of climate variability in the tropical Pacific by analyzing zonal surface wind stress, sea surface temperature, and upper ocean heat content during the period 1967 to 1986. Three principal climate modes could be indentified: The annual cycle, a quasi-biennial (QB) mode, and a low-frequency (LF) mode with a time scale of about 3 years. The annual cycle is mostly governed by the movement of the sun, local air-sea heat exchange and mixing processes. In the eastern equatorial Pacific, the annual cycle involves a westward propagating coupled mode which is caused by processes within the surface mixed layer. The quasi-biennial mode near the equator shows aspects of both mixed layer physics and shallow water wave dynamics and is therefore best described as a `mixed surface/subsurface dynamics` mode. Poleward of 10 degrees local air-sea heat exchange and mixing processes become also important. The low-frequency mode is the traditional ENSO mode, which is best described as the oceanic response to low-frequency atmospheric forcing. Equatorial wave dynamics is crucial for the low-frequency mode. The quasi-biennial mode shows some evidence for a phase-locking to the annual cycle. However, the period of the quasi-biennial mode is not steady, ranging from about 20 to 30 months during the analysed period. Evidence was found that the annual cycle and the quasi-biennual mode together influence the low-frequency mode such that the low-frequency mode attains maximum amplitude several months after the annual cycle and the quasi-biennial mode were in phase. Our study confirms also the existence of non-linear interactions involving the QB and LF modes of interannual variability only. (orig.).}
issue = {no. 91}
place = {Germany}
year = {1992}
month = {Sep}
}