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Titel |
Application of infrared remote sensing to constrain in-situ estimates of ice crystal particle size during SPartICus |
VerfasserIn |
S. J. Cooper, T. J. Garrett |
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 ; 4, no. 8 ; Nr. 4, no. 8 (2011-08-18), S.1593-1602 |
Datensatznummer |
250002077
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Publikation (Nr.) |
copernicus.org/amt-4-1593-2011.pdf |
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Zusammenfassung |
In a prior paper (Cooper and Garrett, 2010), an infrared remote sensing technique was
developed that quantifies the effective radius re of ice crystals in
cirrus clouds. By accounting for a broad range of expected inversion
uncertainties, this retrieval scheme isolates those radiometric signatures
that can only occur if the cirrus has nominally "small" values of re below
20 μm. The method is applicable only for specific cloud and atmospheric
conditions. However, it can be particularly useful in constraining in-situ
estimates of cirrus cloud re obtained from aircraft. Recent studies
suggest that airborne measurements may be compromised by the shattering of
ice crystals on airborne instrument inlets, so robust, independent
confirmation of these measurements is needed. Here, we expand the
Cooper and Garrett (2010) retrieval scheme to identify ice clouds that are likely to
have "large" values of re greater than 20 μm. Using MODIS
observations, we then compare assessments of cirrus cloud re with in-situ
measurements obtained during three test cases from the 2010 SPartICus
campaign. In general, there is good agreement between retrievals and in-situ
measurements for a "small" and "large" crystal case. For a more ambiguously
"small" re case, the 2D-S cloud probe indicates values of re that are
slightly larger than expected from infrared retrievals, possibly indicating a
slight bias in the 2D-S results towards large particles. For our test cases,
there is no evidence to suggest that an FSSP-100 with unmodified inlets
produces measurements of re in cirrus that are strongly biased low. |
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