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| Titel |
Systematic errors in global air-sea CO2 flux caused by temporal averaging of sea-level pressure |
| VerfasserIn |
H. Kettle, C. J. Merchant |
| 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 ; 5, no. 6 ; Nr. 5, no. 6 (2005-06-15), S.1459-1466 |
| Datensatznummer |
250002897
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| Publikation (Nr.) |
 copernicus.org/acp-5-1459-2005.pdf |
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| Zusammenfassung |
| Long-term temporal averaging of meteorological data, such as wind speed and
air pressure, can cause large errors in air-sea carbon flux estimates. Other
researchers have already shown that time averaging of wind speed data creates
large errors in flux due to the non-linear dependence of the gas transfer
velocity on wind speed (Bates and Merlivat, 2001). However, in general, wind
speed is negatively correlated with air pressure, and a given fractional
change in the pressure of dry air produces an equivalent fractional change in
the atmospheric partial pressure of carbon dioxide (pCO2air). Thus
low pressure systems cause a drop in pCO2air, which together with
the associated high winds, promotes outgassing/reduces uptake of CO2 from
the ocean. Here we quantify the errors in global carbon flux estimates caused
by using monthly or climatological pressure data to calculate
pCO2air (and thus ignoring the covariance of wind and pressure)
over the period 1990-1999, using two common parameterisations for gas
transfer velocity. Results show that on average, compared with estimates made
using 6 hourly pressure data, the global oceanic sink is systematically
overestimated by 7% (W92) and 10% (WM99) when monthly mean pressure is
used, and 9% (W92) and 12% (WM99) when climatological pressure is used. |
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