Spatially explicit downscaling of future land use change from GLOBIOM model in the case study region of Heihe River Basin

Xinxin Zhang of the Beijing Forestry University, China, discusses her YSSP project in which she integrated a dynamic recursive cross-entropy-based probabilistic downscaling model with IIASA's GLOBIOM model to downscale global or regional scale land use change assessments to the local level.

X. Zhang

X. Zhang

Introduction

Land use and land cover changes have become a major driver of global and local environmental changes. They particularly affect water consumption and quality, which is  of great concern to international, national, and local policymakers. International and national policymaking will continue to influence land use and to have implication for local land users. Identification of future land use changes can help planners cope with the uncertainty associated with planning for future landscape development. Over the last decades, a range of models of land use changes have been developed to meet land management needs. But many models focus on specific land use changes at global and regional scale, which is insufficient to establish a link with local case studies. Hence, deriving detailed spatio-temporal estimates at the required resolutions at local scale remains a challenge. The Heihe River Basin, a typical inland river basin located in the arid regions of Northwest China, was selected as the basis for studying a downscaling model to project future land use changes from global/regional level to local level at fine resolution.

Methods

We applied an integrated methodology combining the GLOBIOM model with a dynamic recursive cross-entropy-based probabilistic downscaling model to derive spatially detailed projections of land use changes from 2000 to 2050 in the Heihe river basin at 1x1 km resolution, consistent  with aggregate land demand projections generated by GLOBIOM. The SSP 2 and SSP 3 scenarios were selected to study the future land use changes. The simulated land use in 2000 was then compared with the observed land use in 2000 to validate the downscaling model by Kappa statistic. The results of downscaling will be used by the GEPIC/SWAT model to project future water use and to analyze water security in the case study region.

Results

Different dynamic land uses changes in the Heihe river basin (including cropland, grassland, forest, planted forest, deserts, wetlands, permanent ice and snow) from 2000 to 2050 with a time step of 10 years under different SSP scenarios were derived using the downscaling model at 1 km resolution.

Conclusion

This dynamic recursive cross-entropy-based probabilistic downscaling model integrated with the GLOBIOM model allows downscaling of global or regional scale land use change assessments to the local level. The model provides strategic planners with the tools required to envisage the outcome of global and national trends and assess the implications of alternative decisions and planning strategies at fine spatial scales for the analysis of local sustainable land use and water management strategies.

Note

Xinxin Zhang is a citizen of China. She was funded by IIASA's National Member Organization for China and worked in the Ecosystems Services and Management (ESM) Program during the YSSP.

Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.


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Last edited: 19 August 2015

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