Garden with Insight v1.0 Help: Hydrology  Snowmelt
If snow is present, it may be melted on days when the second soil layer temperature exceeds 0 degrees C.
Snow is melted as a function of the snow pack temperature using the equation [Equation 88] where SML
is the snowmelt rate in mm/day, SNO is the snow present in mm of water, T is the mean daily air
temperature in degrees C, and SPT is the snow pack temperature in degrees C.
Equation 88:
SML = T * (1.52 + 0.54 * SPT), 0 <= SML <= SNO
Code:
same
Variables:
SML = Snowmelt_mm
T = meanTempForDay_degC
SPT = snowPackTemp_degC
SNO = snowWaterContent_mm
The snow pack temperature is estimated with the equation [Equation 89] where T(s) is the temperature at
the top of the snow pack and T(2) is the temperature at the center of soil layer 2. The equations for
estimating T(s) and T(2) are presented in the soil temperature section. Melted snow is treated the same as
rainfall for estimating runoff volume and percolation, but rainfall energy is set to 0.0 and peak runoff rate
is estimated by assuming uniformly distributed rainfall for a 24hr duration.
Equation 89:
SPT = min(T(s), T(2))
Code:
SPT = (2.0 * T(surf) + T) / 3.0
Variables:
SPT = SnowPackTemp_degC
T(s) = tempAtTopOfSnowPack_degC
T(2) = tempAtCenterOfSoilLayerTwo_degC
T(surf) = soilSurfaceTemp_degC
T = meanTempForDay_degC
