Throughfall of precipitation
Throughfall in case of only one canopy storage is calculated as:
where fth,d is the fraction of the precipitation that directly reaches the soil surface without being affected by the vegetation.
In case of multiple canopies the throughfall is separated in a direct fraction, fth,d, and a bypassing fraction, fth,b, i.e. drops from one canopy to the other. The flux is calculated from above and downwards splitting the canopy storage into two equally high segments. The direct fraction of throughfall is passing each mid point of canopies from top to bottom. The indirect fraction is always bypassing one segment. The bypassing fraction, fth,b, is calculated as:
where cmax and cLAIsens are parameters given in a table. See viewing function Rain Interception Canopy Cover Function.