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| Titel |
Methanol from TES global observations: retrieval algorithm and seasonal and spatial variability |
| VerfasserIn |
K. E. Cady-Pereira, M. W. Shephard, D. B. Millet, M. Luo, K. C. Wells, Y. Xiao, V. H. Payne, J. Worden |
| 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 ; 12, no. 17 ; Nr. 12, no. 17 (2012-09-12), S.8189-8203 |
| Datensatznummer |
250011441
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| Publikation (Nr.) |
 copernicus.org/acp-12-8189-2012.pdf |
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| Zusammenfassung |
| We present a detailed description of the TES methanol (CH3OH) retrieval
algorithm, along with initial global results showing the seasonal and
spatial distribution of methanol in the lower troposphere. The full
development of the TES methanol retrieval is described, including
microwindow selection, error analysis, and the utilization of a priori and
initial guess information provided by the GEOS-Chem chemical transport
model. Retrieval simulations and a sensitivity analysis using the developed
retrieval strategy show that TES: (i) generally provides less than 1.0
piece of information, (ii) is sensitive in the lower troposphere with peak
sensitivity typically occurring between ~900–700 hPa
(~1–3 km) at a vertical resolution of ~5 km,
(iii) has a limit of detectability between 0.5 and 1.0 ppbv Representative
Volume Mixing Ratio (RVMR) depending on the atmospheric conditions,
corresponding roughly to a profile with a maximum concentration of at least
1 to 2 ppbv, and (iv) in a simulation environment has a mean bias of 0.16 ppbv
with a standard deviation of 0.34 ppbv. Applying the newly derived TES
retrieval globally and comparing the results with corresponding GEOS-Chem
output, we find generally consistent large-scale patterns between the two.
However, TES often reveals higher methanol concentrations than simulated in
the Northern Hemisphere spring, summer and fall. In the Southern Hemisphere,
the TES methanol observations indicate a model overestimate over the bulk of
South America from December through July, and a model underestimate during
the biomass burning season. |
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