Climate Modeling

Earth System Modeling

The Earth System Modeling (ESM) program (website) supports the development of coupled global climate models to project climate change in support of the Department of Energy's (DOE) missions in energy and environments. ESM collaborates with the Terrestrial Ecosystem Science (TES) program to build climate-relevant representations of physical and biogeochemical processes in land models. The field, observational, and process-resolving modeling activities in TES are used to develop and test global-scale land modeling representations. In turn, uncertainties or errors in ESM land simulations point to requirements for in-depth TES research.   ESM serves as a climate system integrator, combining land with other system components for climate projections, study of system feedbacks, and tipping points.  Most recently, ESM is supporting a new high-resolution, coupled climate simulation and projection capability, the Accelerated Climate Model for Energy (ACME), which will be particularly designed to run efficiently on DOE’s Leadership Class Computing facilities.  ACME developments will be coordinated with TES research needs and contributions. ACME will be integrating recently developed subsurface flow capabilities, soil biogeochemistry (including phosphorus, together with carbon and nitrogen) and soil moisture improvements. ACME’s energy and human components also will involve land, for example, by implementing water management and improved crops.

The program’s general goals are to improve the detailed physical and biogeochemical processes in the Community Earth System Model (CESM); to implement and test variable and high-resolution model components, both individually and in the coupled system; and to optimize model performance with respect to model resolution, model complexity, and scalability on DOE Leadership Class computer architectures. Model development strategies are formulated to enhance climate projection capabilities, improving competencies in simulating climate feedbacks, tipping points, and responses to past and possible future energy pathways. These enhancements are then analyzed more extensively within the Regional and Global Climate Modeling program, which provides feedback to ESM with respect to analysis-driven model development requirements. Specifically, ESM and its collaborations with other Climate and Environmental Sciences Division research activities will advance a capability for improved climate system predictability through advances within the CESM model components (e.g., Consequence Assessment Modeling [CAM], Community Ice CodE [CICE], Ocean Model and Community Seal Ice Model [CSIM]). In collaboration with TES, CLM development priorities include improving model soil moisture, tropical ecosystem dynamics, and evolution of boreal and Arctic land and ecosystems. Additional priorities include improving land-atmosphere interactions, including terrestrial sources of radiatively active gases and aerosols, soil moisture impacts on atmospheric processes, and precipitation influence on terrestrial systems. Global land models will be evaluated and used to guide TES process research by discerning those geographic regions and system representations that are characterized by significant parametric uncertainty.

• Modeling of the full terrestrial-ocean-atmospheric carbon cycle to enable comprehensive understanding of the fluxes and reservoirs of carbon and the relative importance of natural and combustion sources. CESM isotopic capabilities will be enhanced and developed and compared to measurements to further enable this distinction.
• Effective coupling of the human and natural systems within ESMs, building upon partnerships with Integrated Assessment Research. This modeling collaboration develops and couples CESM components to explore critical human-climate interactions, such as the impacts of water and land use on the climate system and the implications of water availability on human adaptation and energy choices, as well as an improved understanding of the impacts that energy byproducts have on the climate system.

Contact: Dorothy Koch, Ph.D., Program Manager

Regional and Global Climate Modeling

The focus of the Regional and Global Climate Modeling (RGCM) program (website) is to advance a predictive process-level understanding of climate variability and change over a variety of scales by diagnosing and analyzing state-of-the-science for climate and ESMs. As the representation of terrestrial and oceanic carbon cycles and other biogeochemical processes become increasingly complex within ESMs, there is a critical need to develop effective ways to use new observational and experimental data to constrain model projections and inform model development. The  Biogeochemistry (BGC) Feedbacks (website) Scientific Focus Area (SFA), sponsored by the RGCM program, are to identify and quantify the feedbacks between biogeochemical cycles and the climate system, and to quantify and reduce the uncertainties in ESMs associated with those feedbacks. Five objectives drive the research efforts of the BGC Feedbacks SFA: 1) development of new hypothesis-driven approaches for evaluation of ESM representations of biogeochemical processes at site, regional, and global scales; 2) investigation of the degree to which contemporary observations can be used to reduce uncertainties in future scenarios, using an “emergent constraint” approach that draws upon an ensemble of model simulations; 3) development of an open-source benchmarking software system that leverages the growing collection of laboratory, field, and remote-sensing datasets for systematic evaluation of ESM biogeochemical processes; 4) evaluation of the performance of different ESMs using the benchmarking software system; and 5) providing international leadership for biogeochemistry model evaluation and benchmarking.

As part of the benchmarking efforts, this SFA supports the International Land Model Benchmarking (website; ILAMB) project.  ILAMB is a model-data intercomparison and integration project designed to assess and improve the performance of land models and, in parallel, improve the design of new measurement campaigns to reduce uncertainties associated with key land surface processes. Building upon past model evaluation studies, the goals of ILAMB are to: 1) develop internationally accepted benchmarks for land model performance; 2) promote the use of these benchmarks by the international community for model intercomparison; 3) strengthen linkages between experimental, remote sensing, and climate modeling communities in the design of new model tests and new measurement programs; and 4) support the design and development of a new, open-source, benchmarking software system for use by the international community. This effort is expected to contribute to the Coupled Model Intercomparison Project (CMIP) by providing model analysis and evaluation capabilities for future modeling experiments. ILAMB invites scientists in the TES community to contribute to its development and use.

Contact: Renu Joseph, Ph.D., Program Manager

Visit our sister program, BER Subsurface Biogeochemical Research