E3SM session
E2
Abstract
Land use and land cover changes (LULCCs) play a center role in the societal and earth system modelling. The Integrated Assessment Models (IAMs), which run at the regional scale, are used to simulate the human system dynamics, including the regional LULC demand. Meanwhile, the Earth System Models (ESMs) require gridded LULCC data to study the effects of LULCC on biogeophysics, biogeochemistry and climate. Therefore, it is of great importance to develop LULCC downscaling tools to link the IAMs with ESMs. A limited number of such tools, which downscale the regional LULC to grid scale, are available in the literature. A systemic comparison of different downscaling tools is still lacking. In this study, we use the Spatial Dynamic Allocation Model (SDAM) to downscale the LULC data at the historical time and in the future under the Socio-Economic Pathway scenarios, and compare the downscaled results with other land use and land cover downscaling results such as the Land-Use Harmonization 2. In addition, we use the Energy Exascale Earth System Model (E3SM) Land Model (ELM) to quantify and compare the carbon, energy and water fluxes calculated SDAM-based LULCC data and other LULCC data products. We identify the hotspot regions with great uncertainties in the ELM outputs. We further discuss the possible reasons for these differences based on the different characters of the LULCC products. This study provides a comprehensive understanding of the impacts of global LULCC products and their implications on the land processes.