v1.0.9.48 Param_Sets_GR4J example modified

DESCRIPTION

 Package: airGR
 Type: Package
 Title: Suite of GR Hydrological Models for Precipitation-Runoff Modelling
-Version: 1.0.9.47
+Version: 1.0.9.48
 Date: 2017-09-13
 Authors@R: c(
   person("Laurent", "Coron", role = c("aut", "trl")),

man/Param_Sets_GR4J.Rd

@@ -19,10 +19,10 @@
 
 
 \description{
-These parameter sets can be used for the grid-screening calibration procedure (i.e. first step in \code{\link{Calibration_Michel}}).
-Please note that the given GR4J X4u variable does not correspond to the actual GR4J X4 parameter.
-As explained in Andréassian \emph{et al.} (2014; section 2.1), the given GR4J X4u value has to be adjusted (rescaled) using catchment area (S) [km2] as follows: {X4 = X4u * S^0.3}.
-Please, see the example below.
+These parameter sets can be used as an alternative for the grid-screening calibration procedure (i.e. first step in \code{\link{Calibration_Michel}}).
+Please note that the given GR4J X4u variable does not correspond to the actual GR4J X4 parameter. As explained in Andréassian et al. (2014; section 2.1), the given GR4J X4u value has to be adjusted (rescaled) using catchment area (S) [km2] as follows: {X4 = X4u / 5.995 * S^0.3}.
+3 (please note that the formula is erroneous in the publication). Please, see the example below. \cr
+As shown in Andréassian et al. (2014; figure 4), only using these parameters sets as the tested values for calibration is more efficient than a classical calibration when the amount of data is low (6 months or less).
 }
 
 
@@ -48,8 +48,8 @@ data(L0123001)
 data(Param_Sets_GR4J)
 str(Param_Sets_GR4J)
 
-## generalist parameter sets with real GR4J X4
-Param_Sets_GR4J$X4 <- Param_Sets_GR4J$X4u * BasinInfo$BasinArea^0.3
+## computation of the real GR4J X4
+Param_Sets_GR4J$X4 <- Param_Sets_GR4J$X4u / 5.995 * BasinInfo$BasinArea^0.3
 Param_Sets_GR4J$X4u <- NULL
 Param_Sets_GR4J <- as.matrix(Param_Sets_GR4J)
 
@@ -57,33 +57,47 @@ Param_Sets_GR4J <- as.matrix(Param_Sets_GR4J)
 InputsModel <- CreateInputsModel(FUN_MOD = RunModel_GR4J, DatesR = BasinObs$DatesR, 
                                  Precip = BasinObs$P, PotEvap = BasinObs$E)
 
-## run period selection
-Ind_Run <- seq(which(format(BasinObs$DatesR, format = "\%d/\%m/\%Y \%H:\%M")=="01/01/1990 00:00"), 
-               which(format(BasinObs$DatesR, format = "\%d/\%m/\%Y \%H:\%M")=="31/12/1999 00:00"))
+## ---- calibration step
+
+## short calibration period selection (< 6 months)
+Ind_Cal <- seq(which(format(BasinObs$DatesR, format = "\%d/\%m/\%Y \%H:\%M")=="01/01/1990 00:00"), 
+               which(format(BasinObs$DatesR, format = "\%d/\%m/\%Y \%H:\%M")=="01/03/1990 00:00"))
+
+## preparation of the RunOptions object for the calibration period
+RunOptions_Cal <- CreateRunOptions(FUN_MOD = RunModel_GR4J,
+                               InputsModel = InputsModel, IndPeriod_Run = Ind_Cal)
+
+## simulation and efficiency criterion (Nash-Sutcliffe Efficiency) with all generalist parameter sets on the calibration period
+OutputsCrit_Loop <- apply(Param_Sets_GR4J, 1, function(Param) {
+  OutputsModel_Cal <- RunModel_GR4J(InputsModel = InputsModel, RunOptions = RunOptions_Cal, Param = Param)
+  InputsCrit  <- CreateInputsCrit(FUN_CRIT = ErrorCrit_NSE, InputsModel = InputsModel, 
+                                  RunOptions = RunOptions_Cal, Qobs = BasinObs$Qmm[Ind_Cal])
+  OutputsCrit <- ErrorCrit_NSE(InputsCrit = InputsCrit, OutputsModel = OutputsModel_Cal)
+  return(OutputsCrit$CritValue)
+})
 
-## preparation of RunOptions object
-RunOptions <- CreateRunOptions(FUN_MOD = RunModel_GR4J,
-                               InputsModel = InputsModel, IndPeriod_Run = Ind_Run)
+## best parameter set
+Param_Best <- unlist(Param_Sets_GR4J[which.max(OutputsCrit_Loop), ])
 
-## calibration criterion: preparation of the InputsCrit object
-InputsCrit <- CreateInputsCrit(FUN_CRIT = ErrorCrit_NSE, InputsModel = InputsModel, 
-                               RunOptions = RunOptions, Qobs = BasinObs$Qmm[Ind_Run])
 
-## preparation of CalibOptions object using the generalist parameter sets as starting point
-CalibOptions <- CreateCalibOptions(FUN_MOD = RunModel_GR4J, FUN_CALIB = Calibration_Michel,
-                                   StartParamList = Param_Sets_GR4J)
+## ---- validation step
+
+## validation period selection
+Ind_Val <- seq(which(format(BasinObs$DatesR, format = "\%d/\%m/\%Y \%H:\%M")=="01/01/1991 00:00"), 
+               which(format(BasinObs$DatesR, format = "\%d/\%m/\%Y \%H:\%M")=="31/12/1999 00:00"))
+
+## preparation of the RunOptions object for the validation period
+RunOptions_Val <- CreateRunOptions(FUN_MOD = RunModel_GR4J,
+                                   InputsModel = InputsModel, IndPeriod_Run = Ind_Val)
 
-## calibration
-OutputsCalib <- Calibration(InputsModel = InputsModel, RunOptions = RunOptions,
-                            InputsCrit = InputsCrit, CalibOptions = CalibOptions,
-                            FUN_MOD = RunModel_GR4J, FUN_CRIT = ErrorCrit_NSE, 
-                            FUN_CALIB = Calibration_Michel)
+## simulation with the best parameter set on the validation period
+OutputsModel_Val <- RunModel_GR4J(InputsModel = InputsModel, RunOptions = RunOptions_Val, Param = Param_Best)
 
-## simulation
-Param <- OutputsCalib$ParamFinalR
-OutputsModel <- RunModel(InputsModel = InputsModel, RunOptions = RunOptions, 
-                         Param = Param, FUN = RunModel_GR4J)
+## results preview of the simulation with the best parameter set on the validation period
+plot(OutputsModel_Val, Qobs = BasinObs$Qmm[Ind_Val])
 
-## results preview
-plot(OutputsModel, Qobs = BasinObs$Qmm[Ind_Run])
+## efficiency criterion (Nash-Sutcliffe Efficiency) on the validation period
+InputsCrit_Val  <- CreateInputsCrit(FUN_CRIT = ErrorCrit_NSE, InputsModel = InputsModel, 
+                                RunOptions = RunOptions_Val, Qobs = BasinObs$Qmm[Ind_Val])
+OutputsCrit_Val <- ErrorCrit_NSE(InputsCrit = InputsCrit_Val, OutputsModel = OutputsModel_Val)
 }
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