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| Titel |
MISR empirical stray light corrections in high-contrast scenes |
| VerfasserIn |
J. A. Limbacher, R. A. Kahn |
| 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. 7 ; Nr. 8, no. 7 (2015-07-22), S.2927-2943 |
| Datensatznummer |
250116489
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| Publikation (Nr.) |
 copernicus.org/amt-8-2927-2015.pdf |
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| Zusammenfassung |
| We diagnose the potential causes for the Multi-angle Imaging
SpectroRadiometer's (MISR) persistent high aerosol optical depth (AOD) bias
at low AOD with the aid of coincident MODerate-resolution Imaging
Spectroradiometer (MODIS) imagery from NASA's Terra satellite. Stray light
in the MISR instrument is responsible for a large portion of the high AOD
bias in high-contrast scenes, such as broken-cloud scenes that are quite
common over ocean. Discrepancies among MODIS and MISR nadir-viewing blue,
green, red, and near-infrared images are used to optimize seven parameters
individually for each wavelength, along with a background reflectance
modulation term that is modeled separately, to represent the observed
features. Independent surface-based AOD measurements from the AErosol
RObotic NETwork (AERONET) and the Marine Aerosol Network (MAN) are compared
with MISR research aerosol retrieval algorithm (RA) AOD retrievals for 1118 coincidences to
validate the corrections when applied to the nadir and off-nadir cameras.
With these corrections, plus the baseline RA corrections and enhanced cloud
screening applied, the median AOD bias for all data in the mid-visible
(green, 558 nm) band decreases from 0.006 (0.020 for the MISR standard
algorithm (SA)) to 0.000, and the RMSE decreases by 5 % (27 % compared
to the SA). For AOD558 nm < 0.10, which includes about half
the validation data, 68th percentile absolute AOD558 nm errors for
the RA have dropped from 0.022 (0.034 for the SA) to < 0.02
(~ 0.018). |
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