abstraction
instantiates an object from class of abstraction
# S3 method for base
abstraction(rainfall,abstractionParams)
a vector : a time series of precipitation hyetograph (mm)
a list: including parameters of simple surface and simple canopy methods.
canopyAbstraction
depth of canopy abstraction in (mm). default to zero
surfaceAbstraction
depth of surface abstraction in (mm). default to zero
a list: an object from class of abstraction