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| Titel |
Improving satellite-retrieved aerosol microphysical properties using GOCART data |
| VerfasserIn |
S. Li, R. Kahn, M. Chin, M. J. Garay, Y. Liu |
| 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 ; 8, no. 3 ; Nr. 8, no. 3 (2015-03-09), S.1157-1171 |
| Datensatznummer |
250116207
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| Publikation (Nr.) |
 copernicus.org/amt-8-1157-2015.pdf |
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| Zusammenfassung |
| The Multi-angle Imaging SpectroRadiometer (MISR) aboard
the NASA Earth Observing System's Terra satellite can provide more reliable
aerosol optical depth (AOD) and better constraints on particle size
(Ångström exponent, or ANG), sphericity, and single-scattering albedo (SSA) than many other satellite instruments. However, many aerosol mixtures
pass the algorithm acceptance criteria, yielding a poor constraint, when the
particle-type information in the MISR radiances is low, typically at low
AOD. We investigate adding value to the MISR aerosol product under these
conditions by filtering the list of MISR-retrieved mixtures based on
agreement between the mixture ANG and absorbing AOD (AAOD) values, and
simulated aerosol properties from the Goddard Chemistry Aerosol Radiation
and Transport (GOCART) model. MISR–GOCART ANG difference and AAOD ratio
thresholds for applying GOCART constraints were determined based on
coincident AOD, ANG, and AAOD measurements from the AErosol RObotic NETwork (AERONET). The results were validated by comparing the adjusted MISR aerosol
optical properties over the contiguous USA between 2006 and 2009 with
additional AERONET data. The correlation coefficient (r) between the
adjusted MISR ANG derived from this study and AERONET improves to 0.45,
compared to 0.29 for the MISR Version 22 standard product. The ratio of the
adjusted MISR AAOD to AERONET increases to 0.74, compared to 0.5 for the
MISR operational retrieval. These improvements occur primarily when
AOD < 0.2 for ANG and AOD < 0.5 for AAOD. Spatial and temporal
differences among the aerosol optical properties of MISR V22, GOCART, and
the adjusted MISR are traced to (1) GOCART underestimation of AOD and ANG in
polluted regions; (2) aerosol mixtures lacking in the MISR Version 22
algorithm climatology; (3) low MISR sensitivity to particle type under some
conditions; and (4) parameters and thresholds used in our method. |
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