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Summary:

2.8.6.3. Compaction by Melt

The compaction rate due to melting (C_R3,i) is calculated as the ratio of the change in snow ice mass after melting to the mass before melting. This is expressed as:

(2.8.39) C_R3,i = -[1/Δz_i * ∂Δz_i/∂t]_melt = -1/Δt * max(0, (W_sno,i^n - W_sno,i^(n+1)) / W_sno,i^n)

Melting is identified during the phase change calculations (section 2.6.2). Since snow depth is defined as the average depth of the snow-covered area, the snow depth must also be updated for changes in f_sno when W_sno has changed.

(2.8.40) C_R4,i = [1/Δz_i * ∂Δz_i/∂t]_fsno = -1/Δt * max(0, (f_sno,i^n - f_sno,i^(n+1)) / f_sno,i^n)

Key Points:
- Compaction rate due to melting (C_R3,i) is calculated as the ratio of change in snow ice mass after and before melting.
- Melting is identified during phase change calculations.
- Snow depth must be updated for changes in snow-covered fraction (f_sno) when snow mass (W_sno) changes.
- Compaction rate due to changes in f_sno (C_R4,i) is also calculated.