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The antarctic winter; simulations with climatological and reduced sea‐ice extents
Author(s) -
Mitchell J. F. B.,
Senior C. A.
Publication year - 1989
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49711548602
Subject(s) - climatology , sea ice , southern hemisphere , geology , trough (economics) , troposphere , atmospheric sciences , climate model , northern hemisphere , antarctic sea ice , environmental science , arctic ice pack , climate change , oceanography , economics , macroeconomics
The southern hemisphere climatology of a recent version of the Meteorological Office 11‐layer general circulation model is presented. The simulated climate is compared with observational data, including Meteorological Office operational analyses for the period 1983‐1987. The surface temperatures and depth and position of the antarctic circumpolar trough are substantially more realistic than found in earlier climate models, but the high latitude upper troposphere is still colder than observed giving an excessively strong westerly jet. The sensitivity of the model to changes in the distribution of sea‐ice is investigated and compared with that found in other models. In a first experiment, all southern hemisphere sea‐ice equatorward of 67.5°S was replaced by sea at 271.2 K, and the surface roughness length was reduced from 10 −1 m to 10 −4 m. In a second experiment only the roughness length was changed. It is found that the change in surface roughness contributes substantially to the response to reduced sea‐ice extents. The specification of surface roughness over sea‐ice in numerical models is discussed.