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The variability of the Southern Annular Mode and associations with high latitude weather and climate
Entry ID: ASAC_2540

Abstract: Metadata record for data from ASAC Project 2540
See the link below for public details on this project.

The hemispheric and regional atmospheric circulation influences the Southern Ocean in many and profound ways, including intense air-sea fluxes of momentum, energy, fresh water and dissolved gases. The Southern Ocean ventilates a large fraction of the world ocean and hence these influences are spread globally. We use the NCEP-2 reanalysis dataset to diagnose aspects of the large-scale atmospheric structure and variability and explore how these impact on the Southern Ocean. We discuss how the 'Southern Annular Mode' and the 'Pacific-South American' pattern influence the Southern Ocean, particularly in the Eastern Pacific. We review the importance of atmospheric eddies in Southern Ocean climate, and the role they play in transport of mechanical energy into the ocean. The fluxes of fresh water across the air-sea boundary influence strongly the processes of water mass formation. It is shown that climatological precipitation exceeds evaporation over most of the Southern Ocean. When averaged over the ocean from 50S to the Antarctic coast the annual mean excess is 0.8 mm per day. The magnitude of the flux displays only a small measure of seasonality, and it's largest value of 0.92 mm per day occurs in summer.

In this project, the NCEP reanalysis datasets were sourced from: NOAA/National Weather Service, National Centers for Environmental Prediction (5200 Auth Road, Camp Springs, Maryland, 20746 USA).

Two NCEP reanalysis data sets were used in this study. The first was NCEP/NCAR, with 6-hourly data available from 1958 (see the URL provided below for further information). The second was the NCEP/DOE set, with 6-hourly data available from 1979 (see the URL provided below for further information).

The ERA-40 is a 're-analysis' of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions.

The HadISST1.1 data set was the first version of the global sea-ice and sea surface temperature dataset produced by the Hadley Centre at the United Kingdom Meteorological Office.

In this project the following model/analysis was applied:

Application of The University of Melbourne cyclone tracking scheme (Simmonds et al., 2003, Monthly Weather Review, 131, 272-288) and a broad range of statistical tests. Brief details are provided in the Summary. See the link for the pdf document for more detailed information.

These complex statistical analyses were run over the entire length of the project (2004/05 - 2006/07). They were run on Dell PCs in the School of Earth Sciences, The University of Melbourne.

Related URL
Link: View Related Information
Description: Download point for the data - pdf document detailing the model used - AAAD Staff Only

Link: View Related Information
Description: Public information for ASAC project 2540

Link: View Related Information
Description: NCEP/NCAR, with 6-hourly data available from 1958

Link: View Related Information
Description: NCEP/DOE set, with 6-hourly data available from 1979

Link: View Related Information
Description: Citation reference for this metadata record and dataset

Geographic Coverage
 N: -50.0 S: -70.0  E: 180.0  W: -180.0

Data Set Citation
Dataset Originator/Creator: Simmonds, I.
Dataset Title: The variability of the Southern Annular Mode and associations with high latitude weather and climate
Dataset Series Name: CAASM Metadata
Dataset Publisher: Australian Antarctic Data Centre
Online Resource:

Temporal Coverage
Start Date: 2004-07-01
Stop Date: 2007-06-30

Location Keywords

Science Keywords
CRYOSPHERE >SEA ICE    [Definition]
OCEANS >SEA ICE    [Definition]
OCEANS >SEA ICE >SEA ICE AGE    [Definition]

ISO Topic Category

SATELLITES    [Information]

The dates provided in temporal coverage are approximate only.

See the links for the source data for further information about the quality of the original datasets.

Access Constraints
A pdf copy of the paper describing the model used is available for download from the provided URL to AAD staff only. Links to the metadata records describing the original data sources are also available at the URLs given below.

Use Constraints
This data set conforms to the PICCCBY Attribution License

Please follow instructions listed in the citation reference provided at when using these data.

Data Set Progress

Originating Center
University of Melbourne

Data Center
Australian Antarctic Data Centre, Australia    [Information]
Data Center URL:

Data Center Personnel
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: metadata at
Contact Address:
Australian Antarctic Division
203 Channel Highway
City: Kingston
Province or State: Tasmania
Postal Code: 7050
Country: Australia

Distribution_Media: HTTP
Distribution_Size: 9.3 MB
Distribution_Format: pdf
Fees: free

Phone: +61 3 9344 7216
Fax: +61 3 9344 7761
Email: simmonds at
Contact Address:
University of Melbourne
School of Earth Sciences
Province or State: Victoria
Postal Code: 3052
Country: Australia

Simmonds, I., K. Keay and E.-P. Lim (2003), Synoptic activity in the seas around Antarctica., Monthly Weather Review, 131, 272-288

Uppala et al. (2005), The ERA-40 re-analysis, Quarterly Journal of the Royal Meteorological Society, 131, 2961-3012

Rayner, N. A., D. E. Parker, P. Frich, E. B. Horton, C. K. Folland and L. V. Alexander (2000), The HadISST1 Global Sea-Ice and Sea Surface Temperature Dataset, 1871-1999., Hadley Centre Technical Note, 17, United Kingdom Meteorological Office

Rayner, N. A., P. Brohan, D. E. Parker, C. K. Folland, J. J. Kennedy, M. Vanicek, T. J. Ansell and S. F. B. Tett (2006), Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century: The HadSST2 dataset, Journal of Climate, 19, 446-469

Creation and Review Dates
DIF Creation Date: 2005-03-02
Last DIF Revision Date: 2016-11-18

Link to Web Site