Solar radiation interacts differently with various clouds depending on the clouds’ thickness, water content and particle sizes and shapes. Lately, aerosols have gained attention in the climate science community as another mystery in the mix, as they have been found to alter both the lifecycle and properties of clouds.

Together, these field studies will obtain data from various cloud types—cirrus, marine and mixed-phase (ice and water)—to help improve the computer models that simulate climate change.

The four new research projects are:

Cloud, Aerosol and Precipitation in the Marine Boundary Layer. Scientists will take advantage of the user facility’s ARM Mobile Facility—a heavily instrumented portable atmospheric laboratory—to study low marine clouds and aerosols in the Azores. Led by Dr. Robert Wood from the University of Washington, the new award extends an original 9-month project duration on Graciosa Island from March 2009 to November 2010. Doubling the length of the deployment will provide significantly greater statistical reliability of the relationships between aerosol and cloud properties required for evaluation of climate and process models.

Arctic Lower-Troposphere Observed Structure. This 2-month campaign in 2010 will focus on the fall transition season, when sea ice begins to form and dramatic changes in aerosol and cloud properties occur. Led by Dr. Johannes Verlinde from the Pennsylvania State University, the science team will use a heavily instrumented tethered balloon to make routine ascents and descents in the lower 2 kilometers of the atmosphere at Oliktok Point, Alaska. Supplemented with measurements from an instrumented ground station, this campaign will be the first to capture a full atmospheric profile of in situ cloud microphysics, aerosols and radiative measurements during the Arctic transition season. The unique data set will provide a thorough case for testing Arctic cloud processes used in climate models, and for testing the algorithms used to retrieve these measurements.

Small Particles in Cirrus Clouds. Mid-latitude cirrus clouds are the focus of this study that will use instrumented aircraft to sample clouds above the user facility’s Southern Great Plains site in Oklahoma. Led by Dr. Jay Mace from the University of Utah, this field campaign will occur between October 2009 and June 2010, spanning the time of year when cirrus clouds are shown to be most prevalent above the site. Data from the campaign will help scientists to address many outstanding questions regarding mid-latitude cirrus properties and processes, and to validate and implement improved algorithms for measurements of cirrus clouds at all the user facility’s research sites.

An intensive phase of the project will focus more on microphysical processes and field a more extensive set of experimental probes that observe the aerosol and ice nuclei properties of the upper troposphere. DOE and NASA will jointly conduct the intensive phase of the experiment.

Storm Peak Lab Cloud Property Validation Experiment. Dr. Mace is also the lead scientist for the study of liquid and mixed-phase clouds at the Storm Peak Laboratory near Steamboat Springs, Colorado. This campaign will debut the user facility’s second mobile unit, which is currently under development. It will be deployed from approximately October 2010 through March 2011 at a location near the laboratory, which operates at an elevation of 3210 meters above sea level. The close proximity of the mobile facility and the laboratory’s instrument platform is expected to result in a correlative data set equivalent to between 200 and 300 aircraft flights in liquid and mixed-phase clouds.

Funding for the field campaigns is subject to appropriation. The ARM Program is funded through the US Department of Energy’s Office of Science.