ScalePar: Scale 'par.txt' files to different model time step

Description

ScalePar scales time step-dependent parameters and recession coefficients in an imported HYPE 'par.txt' parameter file to a new target time step. See HYPE wiki tutorial on sub-daily time steps.

Usage

ScalePar(
  x = NULL,
  timestep.ratio = 1/24,
  digits = 3,
  verbose = TRUE,
  print.par = FALSE
)

Value

A list() object as supplied in x, with re-scaled parameters and recession coefficients, or nothing if print.par = TRUE.

Arguments

x: List containing HYPE parameters. Typically imported with ReadPar().
timestep.ratio: Numeric, time step scaling factor. Defaults to (1/24) to scale from daily to hourly time steps. To scale from hourly to daily time steps use 24.
digits: Integer, number of significant digits in scaled parameter values to export. See signif().
verbose: Logical, if TRUE, then information will be printed.
print.par: Logical, print known time-scale dependent parameters and recession coefficients instead of scaling a parameter list.

Details

ScalePar applies a user-specified scaling factor, timestep.ratio, to all time scale-dependent parameters and recession coefficients in a HYPE parameter list. Parameters are matched against an inbuilt set of parameter names. To see these parameters, call ScalePar(print.par = TRUE). Please notify us if you find any missing parameters.

If parameters are not timestep-dependent recession coefficients, then scaling is performed using the ratio between the two time step lengths (e.g. 1/24 when scaling from daily to hourly time steps). If parameters are timestep-dependent recession coefficients, then scaling is performed using the relationship described in: Nalbantis, Ioannis (1995). “Use of multiple-time-step information in rainfall-runoff modelling”, Journal of Hydrology 165, 1-4, pp. 135–159.

new_parameter_value = 1 - (1 - old_parameter_value)^time_step_ratio

ScalePar does not scale the values for the "gratk", "ilratk", "olratk", or "wetrate" rating curve parameters in par.txt because they are not limited to the range 0-1. Likewise, HYPEtools does not provide any scaling function for the "RATE" columns in DamData.txt and LakeData.txt because these values are not limited to the range 0-1. We recommend looking at the results from the lakes/wetlands and recalibrating these parameters and their related power coefficients as needed.

Use the ScaleAquiferData and ScaleFloodData functions to scale the time-dependent recession coefficients in AquiferData.txt and FloodData.txt files, respectively.

Examples

Run this code

# Import daily HYPE parameter file
par <- ReadPar(filename = system.file("demo_model", "par.txt", package = "HYPEtools"))
# Scale to hourly time steps
ScalePar(x = par)
# Print all time scale-dependent parameters known to the function
ScalePar(print.par = TRUE)