Causes of variability in the summertime Antarctic boundary-layer climate
A high-resolution one-dimensional atmospheric model is used to assess the contribution of various surface characteristics and external forcings on the structure and dynamics of the atmospheric boundary layer (ABL) over the Antarctic Plateau in summer. The reference run simulates the boundary layer o...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/42728 2023-07-23T04:15:10+02:00 Causes of variability in the summertime Antarctic boundary-layer climate van As, D. van den Broeke, M.R. Marine and Atmospheric Research Afd Marine and Atmospheric Research Sub Dynamics Meteorology 2007 application/pdf https://dspace.library.uu.nl/handle/1874/42728 other unknown 0899-8418 https://dspace.library.uu.nl/handle/1874/42728 info:eu-repo/semantics/EmbargoedAccess Article 2007 ftunivutrecht 2023-07-01T23:40:57Z A high-resolution one-dimensional atmospheric model is used to assess the contribution of various surface characteristics and external forcings on the structure and dynamics of the atmospheric boundary layer (ABL) over the Antarctic Plateau in summer. The reference run simulates the boundary layer over a mildly sloping surface (1.5 m km-1) for a clear sky near the end of the Antarctic summer (31 January-3 February). The ABL depth is approximately 100 m. At night, a low-level jet forms due to the combined effect of katabatic forcing and an inertial oscillation. During the day a convective mixed layer is present. As expected, the ABL is very sensitive to surface slope; a larger slope forces higher wind speeds and a deeper boundary layer. Over a horizontal surface, a nocturnal jet is also found as a result of the inertial oscillation. A modest change in surface albedo alters the mixed-layer temperature and the height and strength of the nocturnal jet considerably. Rotating the large-scale wind relative to the slope direction also has a large impact on ABL depth and structure. The deepest boundary layer and largest wind speed over a northward down-sloping surface are found for an easterly (cross slope) large-scale wind, as is typical for Antarctica. A very shallow ABL with low wind speed is found for the opposite large-scale wind direction. ABL sensitivity to surface roughness was found to be small. For all experiments, the ABL sensitivity is enhanced due to the positive feedback between the cooling of the ABL and katabatic wind speed. Article in Journal/Newspaper Antarc* Antarctic Antarctica Utrecht University Repository Antarctic The Antarctic |
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Utrecht University Repository |
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description |
A high-resolution one-dimensional atmospheric model is used to assess the contribution of various surface characteristics and external forcings on the structure and dynamics of the atmospheric boundary layer (ABL) over the Antarctic Plateau in summer. The reference run simulates the boundary layer over a mildly sloping surface (1.5 m km-1) for a clear sky near the end of the Antarctic summer (31 January-3 February). The ABL depth is approximately 100 m. At night, a low-level jet forms due to the combined effect of katabatic forcing and an inertial oscillation. During the day a convective mixed layer is present. As expected, the ABL is very sensitive to surface slope; a larger slope forces higher wind speeds and a deeper boundary layer. Over a horizontal surface, a nocturnal jet is also found as a result of the inertial oscillation. A modest change in surface albedo alters the mixed-layer temperature and the height and strength of the nocturnal jet considerably. Rotating the large-scale wind relative to the slope direction also has a large impact on ABL depth and structure. The deepest boundary layer and largest wind speed over a northward down-sloping surface are found for an easterly (cross slope) large-scale wind, as is typical for Antarctica. A very shallow ABL with low wind speed is found for the opposite large-scale wind direction. ABL sensitivity to surface roughness was found to be small. For all experiments, the ABL sensitivity is enhanced due to the positive feedback between the cooling of the ABL and katabatic wind speed. |
author2 |
Marine and Atmospheric Research Afd Marine and Atmospheric Research Sub Dynamics Meteorology |
format |
Article in Journal/Newspaper |
author |
van As, D. van den Broeke, M.R. |
spellingShingle |
van As, D. van den Broeke, M.R. Causes of variability in the summertime Antarctic boundary-layer climate |
author_facet |
van As, D. van den Broeke, M.R. |
author_sort |
van As, D. |
title |
Causes of variability in the summertime Antarctic boundary-layer climate |
title_short |
Causes of variability in the summertime Antarctic boundary-layer climate |
title_full |
Causes of variability in the summertime Antarctic boundary-layer climate |
title_fullStr |
Causes of variability in the summertime Antarctic boundary-layer climate |
title_full_unstemmed |
Causes of variability in the summertime Antarctic boundary-layer climate |
title_sort |
causes of variability in the summertime antarctic boundary-layer climate |
publishDate |
2007 |
url |
https://dspace.library.uu.nl/handle/1874/42728 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_relation |
0899-8418 https://dspace.library.uu.nl/handle/1874/42728 |
op_rights |
info:eu-repo/semantics/EmbargoedAccess |
_version_ |
1772189176349851648 |