Estimation of the advection effects induced by surface heterogeneities in the surface energy budget
The effect of terrain heterogeneities in one-point measurements is a continuous subject of discussion. Here we focus on the order of magnitude of the advection term in the equation of the evolution of temperature as generated by documented terrain heterogeneities and we estimate its importance a...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/9489/2016/acp-16-9489-2016.pdf |
| Summary: | The effect of terrain heterogeneities in one-point measurements is a
continuous subject of discussion. Here we focus on the order of magnitude of
the advection term in the equation of the evolution of temperature as
generated by documented terrain heterogeneities and we estimate its
importance as a term in the surface energy budget (SEB), for which the
turbulent fluxes are computed using the eddy-correlation method. The
heterogeneities are estimated from satellite and model fields for scales near
1 km or broader, while the smaller scales are estimated through direct
measurements with remotely piloted aircraft and thermal cameras and also by
high-resolution modelling. The variability of the surface temperature fields
is not found to decrease clearly with increasing resolution, and consequently
the advection term becomes more important as the scales become finer. The
advection term provides non-significant values to the SEB at scales larger
than a few kilometres. In contrast, surface heterogeneities at the metre
scale yield large values of the advection, which are probably only
significant in the first centimetres above the ground. The motions that seem
to contribute significantly to the advection term in the SEB equation in our
case are roughly those around the hectometre scales. |
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| ISSN: | 1680-7316 1680-7324 |