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| Titel |
Spatial structures in the heat budget of the Antarctic atmospheric boundary layer |
| VerfasserIn |
W. J. Berg, M. R. Broeke, E. Meijgaard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 2, no. 1 ; Nr. 2, no. 1 (2008-01-08), S.1-12 |
| Datensatznummer |
250000412
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| Publikation (Nr.) |
 copernicus.org/tc-2-1-2008.pdf |
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| Zusammenfassung |
| Output from the regional climate model RACMO2/ANT is used to calculate the heat
budget of the Antarctic atmospheric boundary layer (ABL). The main feature of
the wintertime Antarctic ABL is a persistent temperature deficit compared to
the free atmosphere. The magnitude of this deficit is controlled by the heat
budget. During winter, transport of heat towards the surface by turbulence
and net longwave emission are the primary ABL cooling terms. These processes
show horizontal spatial variability only on continental scales. Vertical and
horizontal, i.e. along-slope, advection of heat are the main warming terms.
Over regions with convex ice sheet topography, i.e. domes and ridges, warming
by downward vertical advection is enhanced due to divergence of the ABL wind
field. Horizontal advection balances excess warming caused by vertical
advection, hence the temperature deficit in the ABL weakens over domes and
ridges along the prevailing katabatic wind. Conversely, vertical advection is
reduced in regions with concave topography, i.e. valleys, where the ABL
temperature deficit enlarges along the katabatic wind. Along the coast,
horizontal and vertical advection is governed by the inability of the
large-scale circulation to adapt to small scale topographic features.
Meso-scale topographic structures have thus a strong impact on the ABL winter
temperature, besides latitude and surface elevation. During summer, this
mechanism is much weaker, and the horizontal variability of ABL temperatures
is smaller. |
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