U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Dissipating Instabilities in Climate Models
Published: July 25, 2011
Posted: August 23, 2011

Climate model simulations are based on solving equations of motions in the atmosphere and ocean. To make the solutions feasible, the equations must be simplified, retaining only the most important terms. However, the solutions to these simpler equations can become unstable, resulting in unrealistic simulations. To address this issue, damping or dissipation is added to smooth out the unrealistic behaviors. Models either implement this dissipation directly, or the numerical methods used to solve the equations include smoothing effects. All climate models need smoothing, but there has not been a systematic evaluation of how various models achieve this. DOE-funded researchers have investigated and compared the dissipation processes used in the fluid dynamics component of climate models, providing a comprehensive survey of the diffusion, filters, and fixers in dynamical schemes of over 20 general circulation models. They focused on dissipation used in the Community Atmosphere Model (CAM), part of the DOE-supported Community Earth System Model (CESM) at the National Center for Atmospheric Research. Using idealized test cases, the investigators isolated causes and effects of individual dissipation mechanisms, demonstrating that the choice of the dissipation processes directly impacts the accuracy and stability of the simulations. Dissipation even has the potential to alter the large-scale circulation pattern and thereby the outcome of climate simulations. The survey reveals the important role that the stabilizing methods have on atmospheric dynamics and offers practical guidance in choosing adequate subgrid-scale mixing schemes.

Reference: Jablonowski, C., and D. L. Williamson. 2011. "The Pros and Cons of Diffusion, Filters, and Fixers in Atmospheric General Circulation Models," published in Lauritzen, P. H., C. Jablonowski, M. A. Taylor, R. D. Nair (Eds.), Numerical Techniques for Global Atmospheric Models, Lecture Notes in Computational Science and Engineering, Springer, Vol. 80, 381–493. DOI: 10.1007/978-3-642-11640-7_13. (Reference link).

Contact: Renu Joseph, SC-23.1, (301) 903-9237, Dorothy Koch, SC-23.1, (301) 903-0105
Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling

Division: SC-23.1 Climate and Environmental Sciences Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]

Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]

Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]

Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]

Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]

List all highlights (possible long download time)