Knowledge of albedo is of critical importance to land surface monitoring and modelling, particularly with regard to considerations of climate and 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 have shown
that it can vary significantly both spatially and temporally. That said, being an angular and spectral integral, it is relatively conservative inter-annually,
other than due to factors such as snow and possibly fire and dramatic land cover change. As particularly high changes in albedo occur due to the
presence of absence of snow, modellers tend to consider these two cases separately: a snow free albedo and one with snow included.
Descriptions of what is proposed to be done by a small group of different end users is described HERE.
Leaf Area Index (LAI) and fAPAR (fraction of Photosynthetically Active
Radiation) are important measures for the monitoring of plant canopies.
They can be used in vegetation models to restrain primary production and the
terrestrial CO_2 sink. LAI is an Essential Climate Variable (ECV) in the sense
of the WMO, important both for adaption and modeling.