Vosper, SB, Hughes, JK, Lock, AP et al. (4 more authors) (2014) Cold-pool formation in a narrow valley. Quarterly Journal of the Royal Meteorological Society, 140 (679). pp. 699-714. ISSN 0035-9009
Abstract
A numerical model simulation of the formation of a cold pool within a narrow valley during a clear calm night is presented. The results are compared with measurements made during the COLd air Pooling EXperiment (COLPEX). It is demonstrated that the model provides a realistic simulation of the observed cold pool. The cold pool begins to form approximately 1.5 hours before sunset, when the near-surface air within the valley starts to cool more rapidly than the air on the surrounding hills. The model potential temperature budget is used to determine which physical processes are most important for the evolution of the cold pool. The results show that sheltering provided by the valley causes a turbulent heat flux divergence over the lowest 5 m above the valley floor, which is large compared with the other terms in the budget. This causes relatively rapid cooling of the air adjacent to the ground. On the surrounding hills the turbulent heat flux divergence is larger than in the valley, but the enhanced cooling this provides is approximately balanced by an almost equally large warming tendency from advection. The net effect of these two terms is small compared with that in the valley and therefore the cooling rate is smaller. Above 5 m, the cooling in the valley is dominated by local transport of cold air away from the surface into the interior valley atmosphere.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Keywords: | COLPEX; stable boundary layer; sheltering; drainage flow; orography |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/I007679/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 19 Aug 2014 15:03 |
Last Modified: | 29 Oct 2020 11:48 |
Published Version: | http://dx.doi.org/10.1002/qj.2160 |
Status: | Published |
Publisher: | Royal Meteorological Society |
Identification Number: | 10.1002/qj.2160 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80029 |