R/NPPmodel.R

In soilassessment: Assessment Models for Agriculture Soil Conditions and Crop Suitability

NPPmodel=function(rain,temperature,model="miami"){
  if(model=="miami"){
  npprain=3000*(1-exp(-0.000664*rain))
  npptemp=3000/(1+exp(1.315-0.119*temperature))
  npp=min(npprain,npptemp)}
  else if(model=="schuur"){
    npprain=(0.005215*(rain)^1.12363)/exp(0.000459532*rain)
    npptemp=17.6243/(1+exp(1.3496-0.071514*temperature))
    npp=min(npprain,npptemp)*200
  }
  else if(model=="NCEAS"){
    npprain=(0.551*(rain)^1.055)/exp(0.000306*rain)
    npptemp=2540/(1+exp(1.584-0.0622*temperature))
    npp=min(npprain,npptemp)*2
  }
  return(npp)
}