R/par_derive.R

In RHydro: Classes and methods for hydrological modelling and analysis

par_derive <- function(smodl,mparam) {
   # Computes derived model parameters (bucket sizes, etc.)
   # Author: Claudia Vitolo
   #
   # Args:
   #   smodl:                         list of model components
   #   mparam:                        list of model parameters containing the following:
   #                                     rferr_add = additive rainfall error (mm day-1)
   #                                     rferr_mlt = multiplicative rainfall error (-)
   #                                     frchzne   = prms: frac tension storage in recharge zone (-)
   #                                     fracten   = frac total storage as tension storage (-)
   #                                     maxwatr_1 = maximum total storage in layer1 (mm)
   #                                     percfrac  = fraction of percolation to tension storage (-)
   #                                     fprimqb   = sac: fraction of baseflow in primary resvr (-)
   #                                     qbrate_2a = baseflow depletion rate for primary resvr (day-1)
   #                                     qbrate_2b = baseflow depletion rate for secondary resvr (day-1)
   #                                     qb_prms   = baseflow depletion rate (day-1)
   #                                     maxwatr_2 = maximum total storage in layer2 (mm)
   #                                     baserte   = baseflow rate (mm day-1)
   #                                     rtfrac1   = fraction of roots in the upper layer (-)
   #                                     percrte   = percolation rate (mm day-1)
   #                                     percexp   = percolation exponent (-)
   #                                     sacpmlt   = multiplier in the sac model for dry lower layer (-)
   #                                     sacpexp   = exponent in the sac model for dry lower layer (-)
   #                                     iflwrte   = interflow rate (mm day-1)
   #                                     axv_bexp  = arno/vic "b" exponent
   #                                     sareamax  = maximum saturated area
   #                                     loglamb   = mean value of the log-transformed topographic index (m)
   #                                     tishape   = shape parameter for the topo index gamma distribution (-)
   #                                     qb_powr   = baseflow exponent (-)
   #                                     fraclowz  = fraction of soil excess to lower zone (-) # NOT USED
   #
   # Returns:
   #   List of derived parameters.

   # BUCKETSIZE
   maxtens_1  <- mparam$fracten * mparam$maxwatr_1           # derive maximum tension water in upper layer
   maxfree_1  <- (1-mparam$fracten) * mparam$maxwatr_1       # derive maximum free water in upper layer

   maxtens_2  <- mparam$fracten * mparam$maxwatr_2           # derive maximum tension water in lower layer
   maxfree_2  <- (1-mparam$fracten) * mparam$maxwatr_2       # derive maximum free water in lower layer
   
   # derive capacities of the recharge and lower zone (only used if upper tension is divided in two)
   maxtens_1a <- mparam$frchzne * maxtens_1
   maxtens_1b <- (1-mparam$frchzne) * maxtens_1

   # derive capacities of the primary and secondary parallel baseflow reservoirs
   maxfree_2a <- mparam$fprimqb * maxfree_2
   maxfree_2b <- (1-mparam$fprimqb) * maxfree_2

   # fraction of roots in the lower layer (-)
   if (smodl$esoil == 61) {
     rtfrac2 <- 1 - mparam$rtfrac1
   }else{
     rtfrac2 <- 0
   }

   # mean of the power-transformed topographic index
   temp    <- mean_tipow(mparam$tishape, mparam$loglamb, mparam$qb_powr)
   maxpow  <- temp[1]    #in fortran code maxpow/10, why??? 
   powlamb <- temp[2]

   # compute baseflow at saturation (used in the sac percolation model)
   qbsat <- qbsaturatn(smodl$arch2,mparam,maxfree_2a,maxfree_2b,powlamb)

   return(list("maxtens_1"   = maxtens_1,
               "maxtens_2"   = maxtens_2,
               "maxfree_1"   = maxfree_1,
               "maxfree_2"   = maxfree_2,
               "maxtens_1a"  = maxtens_1a,
               "maxtens_1b"  = maxtens_1b,
               "maxfree_2a"  = maxfree_2a,
               "maxfree_2b"  = maxfree_2b,
               "maxpow"      = maxpow,
               "powlamb"     = powlamb,
               "qbsat"       = qbsat,
               "rtfrac2"     = rtfrac2))

}