Surface Albedo of the inner Arctic: Validation of the Climate-SAF satellite Albedo Product with in-situ observations

This paper describes a validation study performed by comparing the AVHRR-based Climate-SAF Surface Albedo Product (SAL) to ground truth observations over Greenland (Greenland Climate Network) and the ice-covered Arctic Ocean (Tara floating ice station) over Arctic summer 2007. The AVHRR dataset consists of 2755 overpasses. The SAL algorithm derives the surface broadband albedo from AVHRR channels 1 and 2 using an atmospheric correction, temporal sampling of an observation geometry to smooth out anisotropy effects, and a narrow-to-broadband conversion algorithm. At the Summit and DYE-2 stations on the Greenland ice sheet, instantaneous SAL RMSE is 0.073, weekly RMSE is 0.053. The heterogeneous surface conditions at satellite pixel scale over the stations near the Greenland west coast increase RMSE to over 0.12. Over Tara, the instantaneous SAL RMSE is 0.069, and 0.045 for weekly means. Considering various sources of uncertainty for both satellite retrievals and in situ observations, we conclude that SAL agrees with in situ observations within their limits of accuracy and spatial representativeness.