Abstract
Abstract. 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.
Highlights
Surface albedo has been identified as an important parameter for climate change by the Working Group I within the Intergovernmental Panel on Climate Change (IPCC) (Foster et al, 2007)
The AErosol RObotic NETwork (AERONET) aerosol optical depth (AOD), which is specified for 675 nm, was referenced to 550 nm by using the Angstrom coefficient derived from concurrent observations at 870 nm
The ALBEDOVAL validation study has been performed to assess the quality of the data record
Summary
Surface albedo has been identified as an important parameter for climate change by the Working Group I within the Intergovernmental Panel on Climate Change (IPCC) (Foster et al, 2007). One of the terrestrial ECVs is the land surface albedo This parameter is defined as the ratio of the radiation flux reflected to the incident radiation flux impinging on the surface (SchaepmanStrub et al, 2006). Throughout this paper we use the variable directional hemispherical reflectance (DHR) to refer to black sky albedo and the variable bi-hemispherical albedo under isotropic illumination (BHRiso) to refer to white sky albedo. These two parameters can be used to estimate the actual albedo, the blue sky or BHR under ambient conditions (Pinty et al, 2005).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
