A note on the interception loss equation

Interception is the process in which precipitation is caught by a vegetative canopy and redistributed to the ground, to the atmosphere, or into the plant. Interception loss is that portion of the precipitation which is returned to the atmosphere through evaporation from plant surfaces or is absorbed into the plant. Thus, it is the difference between the precipitation actually occurring over an area and that which reaches the ground. Horton [1919] presented the first comprehensive discussion of the interception process and summarized data collected by himself as well as data published by others. He observed that interception loss was the sum of (1) the stored on the plant surfaces at the end of a storm (and subsequently returned to the atmosphere by evaporation) and (2) the evaporation from wet plant surfaces during a storm.