Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model
The ACASA (Advanced Canopy–Atmosphere–Soil Algorithm) model, with a higher-order closure for tall vegetation, has already been successfully tested and validated for homogeneous spruce forests. The aim of this paper is to test the model using a footprint-weighted tile approach for a clearing with...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-05-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/2945/2018/bg-15-2945-2018.pdf |
| _version_ | 1828527591948025856 |
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| author | K. Gatzsche K. Gatzsche K. Gatzsche W. Babel W. Babel W. Babel E. Falge E. Falge R. D. Pyles K. T. Paw U A. Raabe T. Foken T. Foken |
| author_facet | K. Gatzsche K. Gatzsche K. Gatzsche W. Babel W. Babel W. Babel E. Falge E. Falge R. D. Pyles K. T. Paw U A. Raabe T. Foken T. Foken |
| author_sort | K. Gatzsche |
| collection | DOAJ |
| description | The ACASA (Advanced Canopy–Atmosphere–Soil Algorithm) model, with
a higher-order closure for tall vegetation, has already been
successfully tested and validated for homogeneous spruce
forests. The aim of this paper is to test the model using
a footprint-weighted tile approach for a clearing with
a heterogeneous structure of the underlying surface. The comparison
with flux data shows a good agreement with a footprint-aggregated
tile approach of the model. However, the results of a comparison
with a tile approach on the basis of the mean land use
classification of the clearing is not significantly different. It is
assumed that the footprint model is not accurate enough to separate
small-scale heterogeneities. All measured fluxes are corrected by
forcing the energy balance closure of the test data either by
maintaining the measured Bowen ratio or by the attribution of the
residual depending on the fractions of sensible and latent heat flux
to the buoyancy flux. The comparison with the model, in which the
energy balance is closed, shows that the buoyancy correction for
Bowen ratios > 1.5 better fits the measured data. For lower Bowen
ratios, the correction probably lies between the two methods, but the
amount of available data was too small to make a conclusion. With an
assumption of similarity between water and carbon dioxide fluxes,
no correction of the net ecosystem exchange is necessary for Bowen
ratios > 1.5. |
| first_indexed | 2024-12-11T21:40:35Z |
| format | Article |
| id | doaj.art-c29ffdbed27a498aa227c8770272bd0a |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-11T21:40:35Z |
| publishDate | 2018-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-c29ffdbed27a498aa227c8770272bd0a2022-12-22T00:49:52ZengCopernicus PublicationsBiogeosciences1726-41701726-41892018-05-01152945296010.5194/bg-15-2945-2018Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA modelK. Gatzsche0K. Gatzsche1K. Gatzsche2W. Babel3W. Babel4W. Babel5E. Falge6E. Falge7R. D. Pyles8K. T. Paw U9A. Raabe10T. Foken11T. Foken12University of Bayreuth, formerly the Department of Micrometeorology, Bayreuth, GermanyUniversity of Leipzig, Leipzig Institute for Meteorology, Leipzig, Germanynow at: Leibniz Institute for Tropospheric Research (TROPOS), Department Modelling of Atmospheric Processes, Leipzig, GermanyUniversity of Bayreuth, formerly the Department of Micrometeorology, Bayreuth, GermanyUniversity of Bayreuth, Bayreuth Center of Ecology and Environmental Research (BayCEER), Bayreuth, Germanynow at: University of Bayreuth, Micrometeorology Group, Bayreuth, GermanyMax Planck Institute of Chemistry, Biogeochemistry Department, Mainz, Germanynow at: German Meteorological Service, Agrometeorological Research Center, Braunschweig, GermanyUniversity of California, Department of Land, Air and Water Resources, Davis, California, USAUniversity of California, Department of Land, Air and Water Resources, Davis, California, USAUniversity of Leipzig, Leipzig Institute for Meteorology, Leipzig, GermanyUniversity of Bayreuth, formerly the Department of Micrometeorology, Bayreuth, GermanyUniversity of Bayreuth, Bayreuth Center of Ecology and Environmental Research (BayCEER), Bayreuth, GermanyThe ACASA (Advanced Canopy–Atmosphere–Soil Algorithm) model, with a higher-order closure for tall vegetation, has already been successfully tested and validated for homogeneous spruce forests. The aim of this paper is to test the model using a footprint-weighted tile approach for a clearing with a heterogeneous structure of the underlying surface. The comparison with flux data shows a good agreement with a footprint-aggregated tile approach of the model. However, the results of a comparison with a tile approach on the basis of the mean land use classification of the clearing is not significantly different. It is assumed that the footprint model is not accurate enough to separate small-scale heterogeneities. All measured fluxes are corrected by forcing the energy balance closure of the test data either by maintaining the measured Bowen ratio or by the attribution of the residual depending on the fractions of sensible and latent heat flux to the buoyancy flux. The comparison with the model, in which the energy balance is closed, shows that the buoyancy correction for Bowen ratios > 1.5 better fits the measured data. For lower Bowen ratios, the correction probably lies between the two methods, but the amount of available data was too small to make a conclusion. With an assumption of similarity between water and carbon dioxide fluxes, no correction of the net ecosystem exchange is necessary for Bowen ratios > 1.5.https://www.biogeosciences.net/15/2945/2018/bg-15-2945-2018.pdf |
| spellingShingle | K. Gatzsche K. Gatzsche K. Gatzsche W. Babel W. Babel W. Babel E. Falge E. Falge R. D. Pyles K. T. Paw U A. Raabe T. Foken T. Foken Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model Biogeosciences |
| title | Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model |
| title_full | Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model |
| title_fullStr | Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model |
| title_full_unstemmed | Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model |
| title_short | Footprint-weighted tile approach for a spruce forest and a nearby patchy clearing using the ACASA model |
| title_sort | footprint weighted tile approach for a spruce forest and a nearby patchy clearing using the acasa model |
| url | https://www.biogeosciences.net/15/2945/2018/bg-15-2945-2018.pdf |
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