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

BER Research Highlights


Improved Assessment of Climate Model Clouds
Published: August 01, 2012
Posted: August 20, 2012

Direct comparison of climate-model simulated clouds with satellite observations has been difficult because there are not direct equivalents between the model representation of clouds and what satellites are able to see. To largely solve this issue, a diagnostic tool—the Cloud Feedback Model Intercomparison Project Observation Simulator Package (COSP)—was developed by a group of scientists worldwide, including scientists at Lawrence Livermore National Laboratory (LLNL). By mimicking the satellite view of an atmospheric column with model-specified physical properties, COSP enables a meaningful comparison between modelled clouds and satellite observations overcoming the significant ambiguities in the direct comparison of model simulations with satellite retrievals. LLNL scientists, working with scientists at the National Center for Atmospheric Research (NCAR), have used COSP to assess the latest version of the NCAR/DOE Community Atmosphere Model (CAM5). Multiple independent satellite datasets and their corresponding instrument simulators in COSP were combined to systematically evaluate the model performance. Compared with the earlier atmospheric model version (CAM4), the new CAM5 model, with its more advanced physics, significantly reduces the long-standing errors in simulated clouds by increasing the total cloud fraction, decreasing optically thick clouds, and increasing mid-level clouds. The COSP diagnostics revolutionize the comparison technique, enabling consistent inter-model and observation-model comparisons. Ultimately, by better identifying model cloud biases, COSP will help to reduce uncertainty in climate predictions. This paper was included in the CCSM Earth System Model CESM1 special collection.

Reference: Kay, J. E., B. R. Hillman, S. A. Klein, Y. Zhang, B. Medeiros, R. Pincus, A. Gettelman, B. Eaton, J. Boyle, R. Marchand, and T. P. Ackerman. 2012. "Exposing Global Cloud Biases in the Community Atmosphere Model (CAM) Using Satellite Observations and Their Corresponding Instrument Simulators, Journal of Climate 25, 5190-5207. DOI: 10.1175/JCLI-D-11-00469.1. Community Earth System Model Special Issue. (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
  • Research Area: Atmospheric System Research

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)