Pulse response model on precipitation as defined in Garcia-Mozo et al. 2009 (Agr. For. Meteorlogy)
GRP(par, data)
a vector of parameter values, this is functions specific
input data (see reference for detailed description), data should be formatted using flat_format()
raster or vector with estimated phenophase timing (in DOY)
if (FALSE) {
estimate <- GRP(data = data, par = par)
}