Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica
Katabatic winds dramatically affect the climate of the McMurdo dry valleys, Antarctica. Winter wind events can increase local air temperatures by 30°C. The frequency of katabatic winds largely controls winter (June to August) temperatures, increasing 1°C per 1% increase in katabatic frequency, and i...
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ftportlandstate:oai:pdxscholar.library.pdx.edu:geog_fac-1008 2023-05-15T13:58:46+02:00 Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica Nylen, Thomas H. Fountain, Andrew G. Doran, Peter T. 2004-01-14T08:00:00Z application/pdf https://pdxscholar.library.pdx.edu/geog_fac/9 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1008&context=geog_fac unknown PDXScholar https://pdxscholar.library.pdx.edu/geog_fac/9 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1008&context=geog_fac Geography Faculty Publications and Presentations Katabatic winds -- Antarctica McMurdo Dry Valleys (Antarctica) Climatology -- Antarctica Environmental Sciences text 2004 ftportlandstate 2022-01-09T19:25:32Z Katabatic winds dramatically affect the climate of the McMurdo dry valleys, Antarctica. Winter wind events can increase local air temperatures by 30°C. The frequency of katabatic winds largely controls winter (June to August) temperatures, increasing 1°C per 1% increase in katabatic frequency, and it overwhelms the effect of topographic elevation (lapse rate). Summer katabatic winds are important, but their influence on summer temperature is less. The spatial distribution of katabatic winds varies significantly. Winter events increase by 14% for every 10 km up valley toward the ice sheet, and summer events increase by 3%. The spatial distribution of katabatic frequency seems to be partly controlled by inversions. The relatively slow propagation speed of a katabatic front compared to its wind speed suggests a highly turbulent flow. The apparent wind skip (down-valley stations can be affected before up-valley ones) may be caused by flow deflection in the complex topography and by flow over inversions, which eventually break down. A strong return flow occurs at down-valley stations prior to onset of the katabatic winds and after they dissipate. Although the onset and termination of the katabatic winds are typically abrupt, elevated air temperatures remain for days afterward. We estimate that current frequencies of katabatic winds increase annual average temperatures by 0.7° to 2.2°C, depending on location. Seasonally, they increase (decrease) winter average temperatures (relative humidity) by 0.8° to 4.2° (−1.8 to −8.5%) and summer temperatures by 0.1° to 0.4°C (−0.9% to −4.1%). Long-term changes of dry valley air temperatures cannot be understood without knowledge of changes in katabatic winds. Text Antarc* Antarctica Ice Sheet McMurdo Dry Valleys Victoria Land Portland State University: PDXScholar Victoria Land McMurdo Dry Valleys |
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Open Polar |
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Portland State University: PDXScholar |
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ftportlandstate |
language |
unknown |
topic |
Katabatic winds -- Antarctica McMurdo Dry Valleys (Antarctica) Climatology -- Antarctica Environmental Sciences |
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Katabatic winds -- Antarctica McMurdo Dry Valleys (Antarctica) Climatology -- Antarctica Environmental Sciences Nylen, Thomas H. Fountain, Andrew G. Doran, Peter T. Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica |
topic_facet |
Katabatic winds -- Antarctica McMurdo Dry Valleys (Antarctica) Climatology -- Antarctica Environmental Sciences |
description |
Katabatic winds dramatically affect the climate of the McMurdo dry valleys, Antarctica. Winter wind events can increase local air temperatures by 30°C. The frequency of katabatic winds largely controls winter (June to August) temperatures, increasing 1°C per 1% increase in katabatic frequency, and it overwhelms the effect of topographic elevation (lapse rate). Summer katabatic winds are important, but their influence on summer temperature is less. The spatial distribution of katabatic winds varies significantly. Winter events increase by 14% for every 10 km up valley toward the ice sheet, and summer events increase by 3%. The spatial distribution of katabatic frequency seems to be partly controlled by inversions. The relatively slow propagation speed of a katabatic front compared to its wind speed suggests a highly turbulent flow. The apparent wind skip (down-valley stations can be affected before up-valley ones) may be caused by flow deflection in the complex topography and by flow over inversions, which eventually break down. A strong return flow occurs at down-valley stations prior to onset of the katabatic winds and after they dissipate. Although the onset and termination of the katabatic winds are typically abrupt, elevated air temperatures remain for days afterward. We estimate that current frequencies of katabatic winds increase annual average temperatures by 0.7° to 2.2°C, depending on location. Seasonally, they increase (decrease) winter average temperatures (relative humidity) by 0.8° to 4.2° (−1.8 to −8.5%) and summer temperatures by 0.1° to 0.4°C (−0.9% to −4.1%). Long-term changes of dry valley air temperatures cannot be understood without knowledge of changes in katabatic winds. |
format |
Text |
author |
Nylen, Thomas H. Fountain, Andrew G. Doran, Peter T. |
author_facet |
Nylen, Thomas H. Fountain, Andrew G. Doran, Peter T. |
author_sort |
Nylen, Thomas H. |
title |
Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica |
title_short |
Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica |
title_full |
Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica |
title_fullStr |
Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica |
title_full_unstemmed |
Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica |
title_sort |
climatology of katabatic winds in the mcmurdo dry valleys, southern victoria land, antarctica |
publisher |
PDXScholar |
publishDate |
2004 |
url |
https://pdxscholar.library.pdx.edu/geog_fac/9 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1008&context=geog_fac |
geographic |
Victoria Land McMurdo Dry Valleys |
geographic_facet |
Victoria Land McMurdo Dry Valleys |
genre |
Antarc* Antarctica Ice Sheet McMurdo Dry Valleys Victoria Land |
genre_facet |
Antarc* Antarctica Ice Sheet McMurdo Dry Valleys Victoria Land |
op_source |
Geography Faculty Publications and Presentations |
op_relation |
https://pdxscholar.library.pdx.edu/geog_fac/9 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1008&context=geog_fac |
_version_ |
1766267104937377792 |