Summary of the article:

Glacier Regions and Their Behaviors

The world's glaciers and ice sheets are divided into different regions that vary in three key aspects:

1. Elevation class representation:
   - Some regions have multiple elevation classes, while others have a single elevation class matching the atmospheric topographic height.
   - Some regions also include virtual elevation classes.

2. Glacial melt water treatment:
   - In some regions, glacial melt water runs off and is replaced by ice, assuming an infinite store of glacial ice.
   - In other regions, glacial melt water remains in place until it refreezes, avoiding negative ice runoff but producing less realistic glacier physics.

3. Ice runoff from snow capping:
   - In some regions, the ice runoff remains ice, simulating iceberg calving.
   - In other regions, the ice runoff is melted and runs off as liquid, avoiding unrealistic cooling of the ocean.

The default behaviors for different glacier and ice sheet regions are summarized in a table, highlighting the specific configurations for Greenland, areas inside the standard CISM grid but outside Greenland, Antarctica, and all other regions.

The article notes that the combination of "replaced by ice" melt behavior and "melted" ice runoff in regions inside the standard CISM grid but outside Greenland can lead to non-physical effects, and it recommends limiting the extent of this combined behavior.