Simulate snow mass accumulation and melt based on Orth et al. (2013) https://www.jstor.org/stable/24914341
simulate_snow(df, varnam_temp, varnam_prec, varnam_snow)
A data frame containing columns for air temperature (deg. C), precipitation in liquid form (rain, mm d-1), and precipitation in solid form (snow water equivalents, mm d-1). The column names of the respective variables are provided by the other arguments.
A character string specifying the variable name for air temperature.
A character string specifying the variable name for rain.
A character string specifying the variable name for snow.
Returns a data frame with two added columns: (1) liquid_to_soil
is the rain plus snow melt in mm d-1; (2) snow_pool
is the snow mass
in water equivalents (mm) for each day.