The surface climatology of an ordinary katabatic wind regime in Coats Land, Antarctica

Renfrew, Ian A. ORCID: https://orcid.org/0000-0001-9379-8215 and Anderson, Philip S. (2002) The surface climatology of an ordinary katabatic wind regime in Coats Land, Antarctica. Tellus A, 54 (5). pp. 463-484.

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Abstract

The surface climatology of Coats Land, Antarctica, is described through observations from automatic weather stations, from Halley station, from upper air soundings and from satellite remote sensing. Coats Land consists of the Brunt Ice Shelf and the adjoining continent to the south. The topography of this region is typical of much of the Antarctic coastal fringes: a modest slope (5% at most) and relative uniformity across the slope. A basic climatology broken into site and season is presented. In winter, and to an extent in the equinoctial seasons, the region clearly divides into two dynamical regimes. Over theice shelf winds are usually from the east or occasionally from the west, whereas over the continental slopes winds are from the east to south quadrant. Over the ice shelf the surface layer is about 10 K colder, in terms of potential temperature, than on the continent, and is also more stable than on the steeper parts of the slope. Motivated by case studies, three criteria are developed to select a subset of the data that are katabatic in the sense that the flow is believed to be primarily due to a downslope buoyancy forcing. On the continental slope, the criteria pick out a coherent subset of the data that aretightly clustered in wind speed and wind direction. Typical katabatic winds are from 10° to the east ofthe fall line and 7.5 m s-1 at the steepest part of the slope (5.1 m s-1 higher up). They are rarely morethan 15 m s-1 in this region; hence their description as ordinary, in contrast with those extraordinary katabatic regimes that have been the focus of previous studies. The katabatic flow remains close to adiabatic as it moves down the slope, and is relatively dry near the slope foot. We estimate the flow tobe primarily katabatic at most 40—50% of the time, although it may appear to be katabatic, from windspeed and wind direction characteristics, some 60—70% of the time. There is no coherent katabatic-flow signature on the ice shelf.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups: Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Faculty of Science > Research Groups > Marine and Atmospheric Sciences (former - to 2017)
Faculty of Science > Research Groups > Meteorology, Oceanography and Climate Dynamics (former - to 2017)
Faculty of Science > Research Groups > Climate, Ocean and Atmospheric Sciences (former - to 2017)
Depositing User: Rosie Cullington
Date Deposited: 22 Mar 2011 14:39
Last Modified: 24 Jul 2024 08:32
URI: https://ueaeprints.uea.ac.uk/id/eprint/26892
DOI: 10.3402/tellusa.v54i5.12162

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