Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys
Idealized numerical simulations of thermally driven flows over various valley–plain topographies are performed under daytime conditions. Valley floor inclination and narrowing valley cross sections are systematically varied to study the influence of along-valley terrain heterogeneity on the developi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/15/6589/2015/acp-15-6589-2015.pdf |
| _version_ | 1819073156681302016 |
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| author | J. S. Wagner A. Gohm M. W. Rotach |
| author_facet | J. S. Wagner A. Gohm M. W. Rotach |
| author_sort | J. S. Wagner |
| collection | DOAJ |
| description | Idealized numerical simulations of thermally driven flows over various valley–plain topographies
are performed under daytime conditions. Valley floor inclination and narrowing valley cross sections
are systematically varied to study the influence of along-valley terrain
heterogeneity on the developing boundary layer structure, as well as horizontal and vertical
transport processes. Valley topographies with inclined valley floors of 0.86° increase
upvalley winds by a factor of about 1.9 due to smaller valley volumes (volume effect) and by a
factor of about 1.6
due to additional upslope buoyancy forces. Narrowing the valley cross section by 20 km per
100 km along-valley distance increases upvalley winds by a factor of about 2.6. Vertical mass fluxes out
of the valley are strongly increased by a factor between 1.8 and 2.8 by narrowing the valley cross sections
and by a factor of 1.2 by inclining the valley floor. Trajectory analysis shows
intensified horizontal transport of parcels from the foreland into the valley within the boundary
layer in cases with inclined floors and narrowing cross sections due to increased upvalley winds. |
| first_indexed | 2024-12-21T17:49:09Z |
| format | Article |
| id | doaj.art-c5ea9b89bc164c3c9627b71aee3ce5c2 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-21T17:49:09Z |
| publishDate | 2015-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-c5ea9b89bc164c3c9627b71aee3ce5c22022-12-21T18:55:25ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242015-06-0115126589660310.5194/acp-15-6589-2015Influence of along-valley terrain heterogeneity on exchange processes over idealized valleysJ. S. Wagner0A. Gohm1M. W. Rotach2Institute of Meteorology and Geophysics, University of Innsbruck, AustriaInstitute of Meteorology and Geophysics, University of Innsbruck, AustriaInstitute of Meteorology and Geophysics, University of Innsbruck, AustriaIdealized numerical simulations of thermally driven flows over various valley–plain topographies are performed under daytime conditions. Valley floor inclination and narrowing valley cross sections are systematically varied to study the influence of along-valley terrain heterogeneity on the developing boundary layer structure, as well as horizontal and vertical transport processes. Valley topographies with inclined valley floors of 0.86° increase upvalley winds by a factor of about 1.9 due to smaller valley volumes (volume effect) and by a factor of about 1.6 due to additional upslope buoyancy forces. Narrowing the valley cross section by 20 km per 100 km along-valley distance increases upvalley winds by a factor of about 2.6. Vertical mass fluxes out of the valley are strongly increased by a factor between 1.8 and 2.8 by narrowing the valley cross sections and by a factor of 1.2 by inclining the valley floor. Trajectory analysis shows intensified horizontal transport of parcels from the foreland into the valley within the boundary layer in cases with inclined floors and narrowing cross sections due to increased upvalley winds.http://www.atmos-chem-phys.net/15/6589/2015/acp-15-6589-2015.pdf |
| spellingShingle | J. S. Wagner A. Gohm M. W. Rotach Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys Atmospheric Chemistry and Physics |
| title | Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys |
| title_full | Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys |
| title_fullStr | Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys |
| title_full_unstemmed | Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys |
| title_short | Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys |
| title_sort | influence of along valley terrain heterogeneity on exchange processes over idealized valleys |
| url | http://www.atmos-chem-phys.net/15/6589/2015/acp-15-6589-2015.pdf |
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