U.S. Department of Energy

Pacific Northwest National Laboratory

Demeter - A Land Use Land Cover Downscaling Model

Demeter is a fully extensible, community-based land use land cover (LULC) downscaling and change detection model that allows for customization and/or additions from its user base. The model was created to generate high-resolution gridded time series representations of LULC projections from global, national, and regional models. The downscaling is based on a number of user-defined rules and drivers, including transitions priorities (i.e., crop expansion preferentially into grasslands rather than forests) and spatial constraints (e.g., nutrient availability). Demeter downscales land allocation projections for a region and/or zone to the resolution of the observed spatial data (MODIS, NLCD, etc.) using an intensification and expansion process applied to each LULC type. Land classes from both the observed and projected data are harmonized by a user-defined binning of each class into the desired output LULC types. Continued model development is underway that will accommodate expanded output formats to enable coupling with the Soil and Water Assessment Tool (SWAT), the Community Land Model (CLM), and others. Integration with the Community Surface Dynamics Modeling System (CSDMS) is also underway by wrapping Demeter in a Basic Model Interface (BMI) to allow for component-based coupling.

Downscaling method
Overview of the downscaling method. The figure shows the successive computational steps to downscale a LULC change scenario from 2005 to 2100 (Fig. 3 from Le Page et al. 2016).

Agro-ecological zones used in global change assessment model
Agro-ecological zones (AEZ) used in the global change assessment model (GCAM) for estimation of current and future land productivity. AEZs are delineated based on a combination of climate zones and moisture regimes (Monfreda et al 2009) with the first six AEZs corresponding to tropical climate, the second six corresponding to temperate climate, and the last six corresponding to boreal climate (Fig. 2 from West et al. 2014).

Point of Contact: Chris Vernon

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References

Le Page Y, TO West, R Link, and P Patel. 2016. "Downscaling Land Use and Land Cover from the Global Change Assessment Model for Coupling with Earth System Models." Geoscience Model Development. 9. 3055-3069. DOI:10.5194/gmd-9-3055-2016.

West TO, Y Le Page, M Huang, J Wolf, and AM Thomson. 2014. "Downscaling Global Land Cover Projections from an Integrated Assessment Model for Use in Regional Analyses: Results and Evaluation for the US from 2005-2095. Environmental Research Letters. 9. 064004. DOI:10.1088/1748-9326/9/6/064004.

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