SWE2HS Documentation#
This is the documentation of the swe2hs Python package.
SWE2HS is a conceptual snow density model for transferring daily snow water equivalent (SWE) of the snow cover to snow depth (HS). Some people informally call it JOPACK, which is an acronym for Just density Of the snowPACK.
The density model calculates snow depth at a daily resolution and is driven by the daily snow water equivalent of the snow cover only. The model creates a new layer with a fixed new snow density \(\rho_{new}\) for every increase in SWE such that, over time, a snowpack of individual layers builds up. The density of a layer increases with an exponential decay function towards a time-varying maximum density. The maximum density starts with an initial value at creation time of the layer and subsequently increases towards a higher value based on the overburden a layer has experienced and the occurrence of SWE losses in the snow pack. When SWE decreases, the model removes layers from the top of the snowpack. The layer number \(n\) can thus undergo changes over time based on the number of SWE increases and losses in the snowpack. The model neglects constructive metamorphism, refreezing, and is not able to capture rain-on-snow events which might lead to an increase in SWE but no increase in snow depth.
Citation#
For more information on the model and how it was calibrated, please refer to the model description paper:
Aschauer, J.; Michel, A.; Jonas, T.; Marty, C., 2023: An empirical model to calculate snow depth from daily snow water equivalent: SWE2HS 1.0. Geoscientific Model Development, 16, 14: 4063-4081. doi: 10.5194/gmd-16-4063-2023
The figure shows the schematic modeled snow pack evolution for the station Kühtai in the winter 2001/02. The red dotted line is the measured snow depth (HS), the black solid line bounding the colored area is the modeled snow depth, the thin black lines depict the layer borders within the modeled snowpack, and the coloring refers to the modeled layer densities. The bottom panel shows the daily snow water equivalent time series which was used to force the model. The data for station Kühtai is available from Krajci et al. (2017) [1].