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

Title: Reconstructing the South Pacific Convergence Zone Position during the Presatellite Era: A La Niña Case Study

Abstract

Sixty-four southwest Pacific island meteorological stations were utilized to develop ENSO-related austral warm season (November–April) rainfall climatologies for 1961–90. Historical data for the same station set were then examined for 1955/56, one of the strongest La Niñas of the twentieth century. The pattern for that event was typical of a well-coupled protracted La Niña, with above-normal rainfall (>150%) observed for 17 stations in the case study. Tropical cyclone tracks were also used to illustrate the proximal effects of historical storms on station rainfall. Several stations that were located along the northern edge of the tropical cyclone swarm, but south of a region of anomalously low rainfall, were selected as possible candidates having been close to the mean South Pacific convergence zone (SPCZ) location. Linear interpolations between those stations highlighted a likely SPCZ position for the 1955/56 event. The reconstructed SPCZ location suggested a position southwest of normal, consistent with many La Niñas observed during the satellite era. The 1955/56 SPCZ reconstruction compared favorably with NOAA Cooperative Institute for Research in Environmental Sciences (CIRES) twentieth-century reanalysis (20CR) positions of maximum atmospheric water content and omega (time derivative of pressure that illustrates vertical velocity, and a proxy for convection and SPCZ location)more » at 500 hPa. Comparisons between Global Precipitation Climatology Project (GPCP) warm season rainfall composite plots for several satellite era La Niñas and one well-coupled La Niña event that occurred during 2010/11 to omega at 500 hPa and maximum rainfall amounts suggest that the 1955/56 reconstruction from in situ rainfall measurements captured the SPCZ location. Our results suggest that use of the 20CR could help to identify hemispheric-scale atmospheric circulation features like the SPCZ and improve understanding of ENSO dynamics prior to the satellite era.« less

Authors:
 [1];  [2];  [3];  [4];  [2]
  1. National Inst. of Water and Atmospheric Research Ltd., Auckland (New Zealand)
  2. Inst. of Biometeorology (IBIMET)-Italian National Research Council (CNR), Rome (Italy)
  3. National Inst. of Water and Atmospheric Research Ltd., Wellington (New Zealand)
  4. Univ. of Auckland (New Zealand)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1565090
Resource Type:
Accepted Manuscript
Journal Name:
Monthly Weather Review
Additional Journal Information:
Journal Volume: 140; Journal Issue: 11; Journal ID: ISSN 0027-0644
Publisher:
American Meteorological Society
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Convergence/divergence; La Nina; Rainfall; Summer/warm season; Tropical cyclones; Surface observations

Citation Formats

Lorrey, Andrew, Dalu, Giovanni, Renwick, James, Diamond, Howard, and Gaetani, Marco. Reconstructing the South Pacific Convergence Zone Position during the Presatellite Era: A La Niña Case Study. United States: N. p., 2012. Web. doi:10.1175/mwr-d-11-00228.1.
Lorrey, Andrew, Dalu, Giovanni, Renwick, James, Diamond, Howard, & Gaetani, Marco. Reconstructing the South Pacific Convergence Zone Position during the Presatellite Era: A La Niña Case Study. United States. doi:10.1175/mwr-d-11-00228.1.
Lorrey, Andrew, Dalu, Giovanni, Renwick, James, Diamond, Howard, and Gaetani, Marco. Thu . "Reconstructing the South Pacific Convergence Zone Position during the Presatellite Era: A La Niña Case Study". United States. doi:10.1175/mwr-d-11-00228.1. https://www.osti.gov/servlets/purl/1565090.
@article{osti_1565090,
title = {Reconstructing the South Pacific Convergence Zone Position during the Presatellite Era: A La Niña Case Study},
author = {Lorrey, Andrew and Dalu, Giovanni and Renwick, James and Diamond, Howard and Gaetani, Marco},
abstractNote = {Sixty-four southwest Pacific island meteorological stations were utilized to develop ENSO-related austral warm season (November–April) rainfall climatologies for 1961–90. Historical data for the same station set were then examined for 1955/56, one of the strongest La Niñas of the twentieth century. The pattern for that event was typical of a well-coupled protracted La Niña, with above-normal rainfall (>150%) observed for 17 stations in the case study. Tropical cyclone tracks were also used to illustrate the proximal effects of historical storms on station rainfall. Several stations that were located along the northern edge of the tropical cyclone swarm, but south of a region of anomalously low rainfall, were selected as possible candidates having been close to the mean South Pacific convergence zone (SPCZ) location. Linear interpolations between those stations highlighted a likely SPCZ position for the 1955/56 event. The reconstructed SPCZ location suggested a position southwest of normal, consistent with many La Niñas observed during the satellite era. The 1955/56 SPCZ reconstruction compared favorably with NOAA Cooperative Institute for Research in Environmental Sciences (CIRES) twentieth-century reanalysis (20CR) positions of maximum atmospheric water content and omega (time derivative of pressure that illustrates vertical velocity, and a proxy for convection and SPCZ location) at 500 hPa. Comparisons between Global Precipitation Climatology Project (GPCP) warm season rainfall composite plots for several satellite era La Niñas and one well-coupled La Niña event that occurred during 2010/11 to omega at 500 hPa and maximum rainfall amounts suggest that the 1955/56 reconstruction from in situ rainfall measurements captured the SPCZ location. Our results suggest that use of the 20CR could help to identify hemispheric-scale atmospheric circulation features like the SPCZ and improve understanding of ENSO dynamics prior to the satellite era.},
doi = {10.1175/mwr-d-11-00228.1},
journal = {Monthly Weather Review},
number = 11,
volume = 140,
place = {United States},
year = {2012},
month = {11}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 11 works
Citation information provided by
Web of Science

Save / Share: