Goddard Institute for Space Studies. Parameter derived from direct measurements and satellite observations. B. W. Meeson, F. E. Corprew, J.M.P. McManus, D.M. Myers, J.W. Closs, K.-J. Sun, D.J. Sunday, P.J. Sellers, 1995. Global Precipitation Climatology Project. International Satellite Land Surface Climatology Project.
Mass fraction is the ratio of the mass of water to the mass of dry soil.
Bulletin of the American Meteorological Society, March 1996. National Center for Environmental Predication. National Center for Atmospheric Research. Vegetation index represents the fraction of available light used by plants for photosynthesis. Parameter derived from satellite observations.