Summary of the Article:

Transient Land Use and Land Cover Change in CLM

1. Land Use and Land Cover Change (LULCC) Representation in CLM
- CLM uses an annual time series of the spatial distribution of natural and crop land units, along with the distribution of Plant Functional Types (PFTs) and Crop Functional Types (CFTs) within those land units.
- Additional land use changes are prescribed through crop-specific management of nitrogen fertilizer, irrigation, and wood harvest on tree PFTs.

2. Biogeophysical Impacts of LULCC
- CLM simulates the biogeophysical impacts of LULCC through changes in surface properties, which affect surface albedo, hydrology, and roughness, ultimately impacting energy, moisture, and momentum fluxes to the atmosphere.
- Changes in the distribution of natural and crop vegetation also lead to small fluxes of energy and moisture to the river and atmosphere.

3. Biogeochemical Impacts of LULCC
- CLM simulates the biogeochemical impacts of LULCC through changes in carbon pools and fluxes, as described in Chapter 2.16 of the documentation.

4. LULCC and Ice Sheet Changes
- CLM can also respond to changes in ice sheet areas and elevations when coupled to an evolving ice sheet model, such as the Community Ice Sheet Model (CISM).
- Conservation of water, energy, carbon, and nitrogen is handled similarly for glacier-vegetation transitions as for natural vegetation-crop transitions.