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

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)