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Under the concept of the conceptual HM, the amount of snowfall is always calculated by the temperature \(T\) and the precipitation \(P\) availability. The proportion of snowfall is always determined by the air temperature.

So we can give the function from:

\[P_s = f_{atmosSnow}(D_{atms})\]

to:

\[P_s = f_{atmosSnow}(P, T) = k^*P\] \[0 \leq k^* \leq 1\] where

  • \(P\) is atmos_precpitation_mm

  • \(T\) is atmos_teperature_Cel

  • \(k^*\) is estimated portion

Then the different atmosSnow methods will estimate the portion \(k^*\).

The output density distribution from 2 methods:

Usage

atmosSnow_ThresholdT(
  atmos_precipitation_mm,
  atmos_temperature_Cel,
  param_atmos_thr_Ts
)

atmosSnow_UBC(
  atmos_precipitation_mm,
  atmos_temperature_Cel,
  param_atmos_ubc_A0FORM
)

Arguments

atmos_precipitation_mm

(mm/m2/TS) precipitaion volum

atmos_temperature_Cel

(Cel) the average air temperature in the time phase

param_atmos_thr_Ts

<-1, 3> (Cel) threshold air temperature that snow, parameter for atmosSnow_ThresholdT()

param_atmos_ubc_A0FORM

<0.01, 3> (Cel) threshold air temperature that snow, it can not equal or small than 0, parameter for atmosSnow_UBC()

Value

atmos_snow_mm (mm/m2/TS) snowfall volume

_ThresholdT:

Only a temperature is as the threshold defined, so estimate the portion \(k^*\) as: \[k^{*}=1, \quad T \leq T_s\] where

  • \(T_s\) is param_atmos_thr_Ts

_UBC (Quick and Pipes 1977) :

estimate the portion \(k^*\) as: \[k^* = 1- \frac{T}{T_0}\] \[k^* \geq 0\] where

  • \(T_0\) is param_atmos_ubc_A0FORM

References

Quick MC, Pipes A (1977). “U.B.C. WATERSHED MODEL / Le Modèle Du Bassin Versant U.C.B.” Hydrological Sciences Bulletin, 22(1), 153--161. ISSN 0303-6936, doi:10.1080/02626667709491701 .