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Titel |
Ozone sonde cell current measurements and implications for observations of near-zero ozone concentrations in the tropical upper troposphere |
VerfasserIn |
H. Vömel, K. Diaz |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 3, no. 2 ; Nr. 3, no. 2 (2010-04-29), S.495-505 |
Datensatznummer |
250000978
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Publikation (Nr.) |
copernicus.org/amt-3-495-2010.pdf |
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Zusammenfassung |
Laboratory measurements of the Electrochemical Concentration Cell (ECC)
ozone sonde cell current using ozone free air as well as defined amounts of
ozone reveal that background current measurements during sonde preparation
are neither constant as a function of time, nor constant as a function of
ozone concentration. Using a background current, measured at a defined timed
after exposure to high ozone may often overestimate the real background,
leading to artificially low ozone concentrations in the upper tropical
troposphere, and may frequently lead to operator dependent uncertainties.
Based on these laboratory measurements an improved cell current to partial
pressure conversion is proposed, which removes operator dependent
variability in the background reading and possible artifacts in this
measurement. Data from the Central Equatorial Pacific Experiment (CEPEX)
have been reprocessed using the improved background treatment based on these
laboratory measurements. In the reprocessed data set near-zero ozone events
no longer occur. At Samoa, Fiji, Tahiti, and San Cristóbal, nearly all
near-zero ozone concentrations occur in soundings with larger background
currents. To a large extent, these events are no longer observed in the
reprocessed data set using the improved background treatment. |
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