fitsnowdepth: Derives snow melt coefficient from empirical data

In ilyamaclean/microsnow: Below or above canopy microclimate modelling with R in snowy environments

Derives snow melt coefficient from empirical data

Description

The function fitsnowdepth estimates the snow melt coefficient from empirical data (or the outputs of a more complex model) and returns this along with estimates of snow depth and the RMS error

Usage

fitsnowdepth(
  weather,
  snowdepth,
  precd,
  snowenv = "Taiga",
  STparams,
  plotout = T,
  snowem = 0.99,
  zm = 0.002,
  umin = 0.5,
  astc = 1.5
)

Arguments

weather	a data.frame of weather variables (see details).
snowdepth	a vector fo measured snow depths (cm). Can be interpolated.
precd	a vector of daily precipitation (mm).
snowenv	one of Alpine, Maritime, Prairie, Taiga or Tundra (see details)
STparams	an object of class SnowTparams as returned by fitsnowtemp()
plotout	optional logical indicating whether to plot observed and predicted data
snowem	optionally, numeric value of snow emissivity
zm	optionally, numeric value of roughness length for momentum transfer of snow surface (m)
umin	optionally, numeric value indicating minimum wind speed used in conductivity calculations (m/s)
astc	optionally, numeric value indicating the temperature at which precipitation falls as snow (deg C)

Details

The format and and units of weather must follow that in the example dataset climdata. The entries in weather need to be hourly. If hourly snow depth data are unavailable, they should be derived by interpolation. The paramater snowenv is used to compute snow density following Sturm et al (2010) J Hydrometeorology 11: 1380-1393.

Value

a list of the following:

psnowdepth predicted snow depth (cm)

RMS Root-mean-square error of predicted snow depths (cm)

meltfact a snow melt factor for use with pSnow()

Examples

# Fit snow depth
require(NicheMapR)
# Derive estimates of snow temperature using NicheMapR in place of observed data
nmrout<-runNMRSnow(climdata, precd, 67.367, 26.629, ALTT = 199)
# Derive Snow temperature parameters
STparams<-fitsnowtemp(climdata,precd,nmrout$SNOWDEP,nmrout$SNOWTEMP)
# Fit snow depth model and plot result (red = Observed)
meltfact<-fitsnowdepth(climdata,snowdepth$snowdepth,precd,STparams=STparams)$meltfact

ilyamaclean/microsnow documentation built on April 7, 2023, 8:55 a.m.