Summary of the article on Convection:

Convective Mixing in Lakes

- Convective mixing is based on a coupled lake-atmosphere model that adjusts the lake temperature profile to maintain a stable density.
- For unfrozen lakes, if the density of a layer is greater than the layer above it, the layers are mixed to create a uniform temperature and density profile.
- For frozen lakes, the algorithm is generalized to conserve total enthalpy and ice content, maintaining a continuous ice layer at the top.
- If a layer with ice is below a layer without ice, these layers and all above are mixed to conserve enthalpy.
- The average ice fraction is calculated, and separate temperatures are determined for the frozen and unfrozen fractions of the mixed layers.
- If the total heat content is positive, the extra heat is assigned to the unfrozen layers, keeping the frozen layers at the freezing point.
- If the heat content is negative, the heat deficit is assigned to the ice, keeping the liquid layers at the freezing point.
- For layers containing both ice and liquid, a weighted average temperature is calculated.
- The ice is lumped together at the top of the lake profile.