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| Titel |
Probability density functions of long-lived tracer observations from satellite in the subtropical barrier region: data intercomparison |
| VerfasserIn |
E. Palazzi, F. Fierli, G. P. Stiller, J. Urban |
| 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 ; 11, no. 20 ; Nr. 11, no. 20 (2011-10-26), S.10579-10598 |
| Datensatznummer |
250010145
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| Publikation (Nr.) |
 copernicus.org/acp-11-10579-2011.pdf |
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| Zusammenfassung |
Past studies have shown that a clear relationship exists between the
field of a passive tracer and the Probability Distribution Function
(PDF) of tracer concentrations, which can be exploited to identify the
position and variability of stratospheric barriers to isentropic
mixing.
In the present study, we focus on the dynamical barrier located in the
subtropics. We calculate PDFs of the long-lived tracers nitrous oxide
(N2O) and methane (CH4) from different satellite
instruments: the Microwave Limb Sounder (MLS) on board Aura, the
Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on
board Envisat, the Sub-Millimetre Radiometre (SMR) on board Odin and
the Halogen Occultation Experiment (HALOE) on board UARS, overall
covering the time period of 1992–2009.
An analysis of the consistency among the different sets of data and
their capability of identifying mixing regions and barrier-to-transport
regions in the stratosphere and the subtropical barrier
location is a prime aim of the present study. This is done looking at
the morphological structure of the one- and two-dimensional PDFs of
tracer concentrations measured by the different instruments. The
latter differ in their spatial and temporal sampling and resolution,
and there are some systematic differences in the determination of the
subtropical barrier position that have been highlighted. However, the
four satellite instruments offer an overall consistent picture of the
subtropical barrier annual cycle. There is a strong seasonality
consistently represented, characterized by the wintertime shift of the
subtropical edge toward the summer hemisphere. However, the influence
of the Quasi Biennial Oscillation (QBO) on isentropic transport and
mixing, and by consequence, on the position of the subtropical
barrier, is not equally represented in all satellite data using the
methodology proposed. |
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