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| Titel |
What can tracer observations in the continental boundary layer tell us about surface-atmosphere fluxes? |
| VerfasserIn |
C. Gerbig, J. C. Lin, J. W. Munger, S. C. Wofsy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 2 ; Nr. 6, no. 2 (2006-02-22), S.539-554 |
| Datensatznummer |
250003423
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| Publikation (Nr.) |
 copernicus.org/acp-6-539-2006.pdf |
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| Zusammenfassung |
| We analyze the potential for inferring spatially resolved surface fluxes
from atmospheric tracer observations within the mixed layer, such as from
monitoring towers, using a receptor oriented transport model (Stochastic
Time-Inverted Lagrangian Transport model - STILT) coupled to a simple
biosphere in which CO2 fluxes are represented as functional responses
to environmental drivers (radiation and temperature). Transport and
biospheric fluxes are coupled on a dynamic grid using a polar projection
with high horizontal resolution (~20 km) in near field, and low
resolution far away (as coarse as 2000 km), reducing the number of surface
pixels without significant loss of information. To test the system, and to
evaluate the errors associated with the retrieval of fluxes from atmospheric
observations, a pseudo data experiment was performed. A large number of
realizations of measurements (pseudo data) and a priori fluxes were generated, and
for each case spatially resolved fluxes were retrieved. Results indicate
strong potential for high resolution retrievals based on a network of tall
towers, subject to the requirement of correctly specifying the a priori
uncertainty covariance, especially the off diagonal elements that control
spatial correlations. False assumptions about the degree to which the
uncertainties in the a priori fluxes are spatially correlated may lead to a
strong underestimation of uncertainties in the retrieved fluxes, or, equivalently, to biased retrievals. The
framework presented here, however, allows a conservative choice of the off
diagonal elements that avoids biasing the retrievals. |
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