Albedo

Knowledge of albedo is of critical importance to land surface monitoring and modelling, particularly with regard to considerations of climate forecasting and energy exchanges within the biosphere. When albedo is used in models, it has often been specified as a fixed number for some given land cover type. However, many years of monitoring from single instruments, such as MODIS, have shown that it can vary significantly both spatially and temporally. The International Climate Observing System (ICOS) specifies that albedo should be produced both spectrally and at a higher spatial resolution (50m initially). High resolution albedo is also of great utility to many agricultural and forestry scientists and engineers.

In HR-Albedomap, we exploit the high spectral and spatial resolution of Sentinel-2 MSI (10m, 20m) and the global coverage of the MODIS sensor (500m) to generate a 10m/20m spectral and 20m broadband land surface albedo product for every Sentinel-2 overpass (typically every 5 days).

Sentinel-2 tiles were processed by the UCL team to provide spectral albedos at 6 spectral bands (10m - bands 2-4; 20m - bands 8A, 10 & 12) alongside broadband albedos covering the visible (0.4-7μm), NIR/SWIR (0.7μm) and shortwave (0.3-3μm).

Preliminary assessments indicate that using the JRC TIP modelling system it is possible to generate fAPAR at 20m spatial resolution from these products so opening up the possibility of being able to identify drought conditions which could be translated into target areas for irrigation as well as areas of potential fire hazard.