Summary of the article on the multiple elevation class scheme for glacier land units:

## Multiple Elevation Class Scheme for Glacier Land Units

- Glacier land units in the model contain multiple columns based on surface elevation, known as elevation classes. This is referred to as the "glacier_mec" land unit.
- The default configuration has 10 elevation classes, with lower limits at 0, 200, 400, 700, 1000, 1300, 1600, 2000, 2500, and 3000 m.
- Each column is characterized by a fractional area and surface elevation, which can be overridden by the ice sheet model as the simulation progresses.
- Each glacier_mec column within a grid cell has distinct ice and snow temperatures, snow water content, surface fluxes, and surface mass balance (SMB).
- Atmospheric variables like temperature, humidity, and precipitation are downscaled from the mean grid cell elevation to the elevation of each glacier_mec column, using a specified lapse rate and assuming uniform relative humidity.
- This downscaling allows lower-elevation columns to experience surface melting while higher-elevation columns remain frozen, providing a more accurate simulation of summer melting.
- The same downscaling procedure is applied to non-urban land units within the ice sheet model domain to maintain consistency between the glaciated and non-glaciated portions.
- Glacier_mec columns can be "virtual", meaning they can be active and have model calculations run even if their fractional area is zero. This facilitates the representation of glacial advance and retreat in the two-way coupled case.