Sensitivity of the Southern Hemisphere Semiannual Oscillation in surface pressure to changes in surface boundary conditions

David J. Walland; Ian H. Simmonds

doi:10.3402/tellusa.v50i4.14542

Sensitivity of the Southern Hemisphere Semiannual Oscillation in surface pressure to changes in surface boundary conditions

Tellus

Volume 50 (1998): Issue 4

By: David J. Walland and Ian H. Simmonds

Open Access

|Jan 1998

Abstract

The Melbourne University General Circulation Model has been used to simulate the climateof the Southern Hemisphere and its portrayal of the Semiannual Oscillation (SAO) in surfacepressure has been assessed. The model is shown to underestimate the amplitude of the SAOslightly but simulate its general structure quite well. To assess the relative importance of variousfactors in determining the characteristics of the SAO, we perform several anomaly experiments.In particular, we conduct an experiment where the Antarctic topography is leveled, an experimentwhere the sea ice surrounding the Antarctic continent is removed and also an experimentthat combines the two changes. The impact on the SAO is examined as a means to attempt todetermine what the mechanisms for the changes are. The removal of topography, in particular, is demonstrated to have a great effect on the SAO, while the sea ice makes a more modestimpact but of the opposite nature. Some possible mechanisms are suggested.

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Articles in this issue

DOI: https://doi.org/10.3402/tellusa.v50i4.14542 | Journal eISSN: 3035-9554

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Language: English

Page range: 424 - 441

Submitted on: Sep 10, 1997

Accepted on: Feb 2, 1998

Published on: Jan 1, 1998

Published by: Stockholm University Press

In partnership with: Paradigm Publishing Services

© 1998 David J. Walland, Ian H. Simmonds, published by Stockholm University Press
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 50 (1998): Issue 4