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Titel |
Quality assessment and improvement of the EUMETSAT Meteosat Surface Albedo Climate Data Record |
VerfasserIn |
A. Lattanzio, F. Fell, R. Bennartz, I. F. Trigo, J. Schulz |
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. 10 ; Nr. 8, no. 10 (2015-10-30), S.4561-4571 |
Datensatznummer |
250116654
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Publikation (Nr.) |
copernicus.org/amt-8-4561-2015.pdf |
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Zusammenfassung |
Surface albedo has been identified as an important parameter for
understanding and quantifying the Earth's radiation budget. EUMETSAT
generated the Meteosat Surface Albedo (MSA) Climate Data Record (CDR)
currently comprising up to 24 years (1982–2006) of continuous
surface albedo coverage for large areas of the Earth. This CDR has
been created within the Sustained, Coordinated Processing of
Environmental Satellite Data for Climate Monitoring (SCOPE-CM)
framework. The long-term consistency of the MSA CDR is high and meets
the Global Climate Observing System (GCOS) stability requirements for
desert reference sites. The limitation in quality due to non-removed
clouds by the embedded cloud screening procedure is the most relevant
weakness in the retrieval process. A twofold strategy is applied to
efficiently improve the cloud detection and removal. The first step
consists of the application of a robust and reliable cloud mask, taking
advantage of the information contained in the measurements of the
infrared and visible bands. Due to the limited information available
from old radiometers, some clouds can still remain undetected. A second
step relies on a post-processing analysis of the albedo seasonal
variation together with the usage of a background albedo map in order
to detect and screen out such outliers. The usage of a reliable cloud
mask has a double effect. It enhances the number of high-quality
retrievals for tropical forest areas sensed under low view angles and
removes the most frequently unrealistic retrievals on similar surfaces
sensed under high view angles. As expected, the usage of a cloud mask
has a negligible impact on desert areas where clear conditions
dominate. The exploitation of the albedo seasonal variation for cloud
removal has good potentialities but it needs to be carefully
addressed. Nevertheless it is shown that the inclusion of cloud
masking and removal strategy is a key point for the generation of the
next MSA CDR release. |
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