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

BER Research Highlights


Dust Cools Climate Due to Effects on High-Level Cloud Ice Particles
Published: February 19, 2013
Posted: April 18, 2013

Atmospheric particles, or aerosols, influence climate by blocking incoming solar radiation and by influencing clouds. One of the least understood effects of aerosols is their influence on very cold clouds, which exist toward polar regions and high in the atmosphere. High-atmosphere clouds trap long-wave radiation and warm climate. Dust from natural sources, such as deserts, and from human activities, including disruption of soils and some industrial activities, appears to have an important effect on cold clouds. Researchers, led by a U.S. Department of Energy scientist at Pacific Northwest National Laboratory, used the Community Atmospheric Model version 5 (CAM5) to study the effect of dust on upper tropospheric cirrus clouds through their tendency to enhance ice particle formation as vapor or droplets that freeze on dust (heterogeneous ice nucleation). These ice particles typically fall out or precipitate. Although scarce, heterogeneous ice nuclei could impact ice crystal number concentration, compared to standard droplet (homogeneous) freezing, by initiating ice nucleation earlier, depleting available water vapor, and hindering the occurrence of homogeneous freezing. Using two model formulations that consider homogeneous and heterogeneous nucleation and the competition between them, the team found heterogeneous nucleation on dust aerosols reduces the occurrence frequency of homogeneous nucleation and thus the ice crystal number concentration in the northern hemisphere. These results highlight the importance of quantifying the number concentrations and properties of heterogeneous ice nuclei (mainly dust) in the upper troposphere.

Reference: Liu, X., X. Shi, K. Zhang, E. J. Jensen, A. Gettelman, D. Barahona, A. Nenes, and P. Lawson. 2012. “Sensitivity Studies of Dust Ice Nuclei Effect on Cirrus Clouds with the Community Atmosphere Model CAM5,” Atmospheric Chemistry and Physics 12(24), 1206179. DOI: 10.5194/acp-12-12061-2012. (Reference link)

Contact: Dorothy Koch, SC-23.1, (301) 903-0105, Ashley Williamson, SC-23.1, (301) 903-3120
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)