Publication Date:
2017-02-28
Description:
Clouds play a central role in the Earth's atmosphere, and satellite observations are crucial to monitor clouds and understand their impact on the energy budget and water cycle. Within the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF) a new cloud property data record was derived from geostationary Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) measurements for the time frame 2004–2015. The resulting CLAAS-2 (CLoud property dAtAset using SEVIRI, Edition 2) data record is publicly available via the CM SAF website (doi:10.5676/EUM_SAF_CM/CLAAS/V002). In this paper we present an extensive evaluation of the CLAAS-2 cloud products, which include cloud fractional coverage, thermodynamic phase, cloud top properties, liquid/ice cloud water path and corresponding optical thickness and particle effective radius. Validation and comparisons were performed on both level 2 (native SEVIRI grid and repeat cycle) and level 3 (daily and monthly averages and histograms) data, with reference data sets derived from lidar, microwave and passive imager measurements. The evaluation results show a very good overall agreement, with matching spatial distributions and temporal variability, and small biases attributed mainly to differences in sensor characteristics, retrieval approaches, spatial/temporal samplings and viewing geometries. No major discrepancies were found. Underpinned by the good evaluation results, CLAAS-2 proves its fitness for the envisaged applications such as process studies, e.g. studies of the diurnal cycle of clouds, and the evaluation of regional climate models. The data record is planned to be extended and updated in the future.
Electronic ISSN:
1866-3591
Topics:
Geosciences
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