Summary:

### Modifications to Snow Layer Logic for Lake Columns

The article discusses the modifications made to the snow layer logic in the climate model to account for differences between lake columns and non-lake columns.

Key points:

1. A thickness difference (z_lsa) is used to adjust the minimum resolved snow layer thickness for lake columns compared to non-lake columns. This is done to satisfy the CFL (Courant-Friedrichs-Lewy) condition for the model timestep.

2. The rules for combining and subdividing snow layers are adjusted for lakes to maintain minimum thicknesses of s_min and to increase all target layer thicknesses by z_lsa.
   - The layer combination rules are modified by increasing the layer thickness thresholds by z_lsa.
   - The layer subdivision rules are modified by increasing the thickness thresholds triggering subdivision by 2z_lsa for type (a) subdivisions, and by z_lsa for type (b) shifts.

3. In rare instances where resolved snow layers are present over an unfrozen top lake body layer, the snow layers may be eliminated if enough heat is present in the top layer to melt the snow.

The article references Subin et al. (2012a) for further discussion on these modifications.