The ALBEDO product corresponds to the amount of solar energy reflected by a surface and provides information on the radiative balance, thus on temperature and water balance. The required quantity for these models is the spectrally integrated albedo over 300-3000 nm spectral domain also called broadband albedo . The spectral albedo corresponds to hemispherical reflectance of the canopy, i.e. the bidirectional reflectance integrated over the hemisphere with regards of the view directions.

A simple approach consists in estimating two sorts of albedo:

1. the directional-hemispherical albedo corresponding only to the direct radiation coming from the sun. This albedo is computed for the local solar noon.
2. the bihemispherical albedo corresponding roughly to the diffuse radiation assumed isotropic (Strahler and Muller, 1995).

The albedo is one of the most interesting variable required as a primary input for global circulation models used to forecast short term weather and long term climatic change (Dickinson 1983). It is also mandatory for local to regional estimates of energy and mass exchanges between the earth surface and the atmosphere as described by soil vegetation atmosphere transfer models (SVAT). Most GCMs are still using prescribed field of surface albedo that are often 5%-15% in error from place to place and time to time (Sato et al., 1989).

This product is currently not yet provided operationnally from the VEGETATION instrument but it already exists from another sensor (MODIS). It is also well adapted for real time processing due to possible strong temporal variations.

Properties of the ALBEDO product:

Spatial resolution	1km²
Product accuracy	300m
Projection	Geographic projection (Lat/lon)
Frequency delivery	10 days
Ancillary data	No
Archive available	Albedo archive will only cover the last months of 2007.
Size of Africa	Approx. 120 MB

For more elaborate technical information please take a look at the ALBEDO Product sheet.