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| Titel |
Fast simulators for satellite cloud optical centroid pressure retrievals; evaluation of OMI cloud retrievals |
| VerfasserIn |
J. Joiner, A. P. Vasilkov, P. Gupta, P. K. Bhartia, P. Veefkind, M. Sneep, J. Haan, I. Polonsky, R. Spurr |
| 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 ; 5, no. 3 ; Nr. 5, no. 3 (2012-03-08), S.529-545 |
| Datensatznummer |
250002627
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| Publikation (Nr.) |
 copernicus.org/amt-5-529-2012.pdf |
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| Zusammenfassung |
| The cloud Optical Centroid Pressure (OCP) is a satellite-derived
parameter that is commonly used in trace-gas retrievals to
account for the effects of clouds on near-infrared through
ultraviolet radiance measurements. Fast simulators are desirable
to further expand the use of cloud OCP retrievals into the
operational and climate communities for applications such as
data assimilation and evaluation of cloud vertical structure in
general circulation models. In this paper, we develop and
validate fast simulators that provide estimates of the cloud
OCP given a vertical profile of optical extinction. We use a
pressure-weighting scheme where the weights depend upon optical
parameters of clouds and/or aerosols. A cloud weighting function
is easily extracted using this formulation. We then use fast
simulators to compare two different satellite cloud OCP
retrievals, from the Ozone Monitoring Instrument (OMI), with
estimates based on collocated cloud extinction profiles from a
combination of CloudSat radar and MODIS visible radiance data.
These comparisons are made over a wide range of conditions to
provide a comprehensive validation of the OMI cloud OCP
retrievals. We find generally good agreement between OMI cloud
OCPs and those predicted by CloudSat. However, the OMI cloud
OCPs from the two independent algorithms agree better with each
other than either does with the estimates from CloudSat/MODIS.
Differences between OMI cloud OCPs and those based on
CloudSat/MODIS may result from undetected snow/ice at the
surface, cloud 3-D effects, cases of low clouds obscurred by ground-clutter
in CloudSat observations and by opaque high clouds in CALIPSO lidar
observations, and the fact that CloudSat/CALIPSO only
observes a relatively small fraction of an OMI field-of-view. |
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