Summary:

Precipitation, Evaporation, and Runoff in Land Types

- All precipitation reaches the ground, with no vegetated fraction.
- Snowfall accumulates until it exceeds a minimum thickness, at which point a resolved snow layer is initiated.
- The density of fresh snow is assigned based on the Snow Hydrology submodel.
- Solid precipitation is added immediately to the snow, while liquid precipitation is added to snow layers after accounting for dew, frost, and sublimation.
- If the snow depth exceeds 1000m, additional precipitation and frost deposition is added to the snow-capping.
- If there are resolved snow layers, "evaporation" (evaporation, dew, frost, and sublimation) is treated as over other land units, with unlimited allowed evaporation from the ground.
- If there are no resolved snow layers but snow mass is present, sublimation is calculated based on the minimum of the evaporation rate and the available snow mass.
- Frost production occurs when evaporation is negative and the ground temperature is at or below freezing, unless the top snow layer has completely thawed.
- The snowpack is updated for frost and sublimation, either using the Snow Hydrology submodel or by directly updating the snow ice mass and adjusting the snow depth accordingly.