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| Titel |
A soil diffusion–reaction model for surface COS flux: COSSM v1 |
| VerfasserIn |
W. Sun, K. Maseyk, C. Lett, U. Seibt |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 10 ; Nr. 8, no. 10 (2015-10-02), S.3055-3070 |
| Datensatznummer |
250116594
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| Publikation (Nr.) |
 copernicus.org/gmd-8-3055-2015.pdf |
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| Zusammenfassung |
| Soil exchange of carbonyl sulfide (COS) is the second largest COS flux in
terrestrial ecosystems. A novel application of COS is the separation of gross
primary productivity (GPP) from concomitant respiration. This method requires
that soil COS exchange is relatively small and can be well quantified.
Existing models for soil COS flux have incorporated empirical temperature and
moisture functions derived from laboratory experiments but not explicitly
resolved diffusion in the soil column. We developed a mechanistic
diffusion–reaction model for soil COS exchange that accounts for COS uptake
and production, relates source–sink terms to environmental variables, and has
an option to enable surface litter layers. We evaluated the model with field
data from a wheat field (Southern Great Plains (SGP), OK, USA) and an oak
woodland (Stunt Ranch Reserve, CA, USA). The model was able to reproduce all
observed features of soil COS exchange such as diurnal variations and
sink–source transitions. We found that soil COS uptake is strongly diffusion
controlled and limited by low COS concentrations in the soil if there is COS
uptake in the litter layer. The model provides novel insights into the
balance between soil COS uptake and production: a higher COS production
capacity was required despite lower COS emissions during the growing season
compared to the post-senescence period at SGP, and unchanged COS uptake
capacity despite the dominant role of COS emissions after senescence. Once
there is a database of soil COS parameters for key biomes, we expect the
model will also be useful to simulate soil COS exchange at regional to global
scales. |
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