Joint Center for Earth Systems Technology

UMBC Atmospheric Scientists Use New Instrumentation

To Study Cloud and Aerosols in Exploratory NASA Aircraft Campaigns

The science teams and ER-2 pilot staff for the ACEPOL campaign, huddled in front of the NASA ER-2 aircraft. (Image: ACEPOL Science Team)

Aerosol-cloud interaction continues to puzzle climate scientists. It is among the most significant contributors to our climate but least understood. Aerosol-cloud processes are poorly represented in climate models and measurement requires high accuracy, narrow resolution, and cooperation between different instruments.

Several studies converge on the idea that a multi-angle imaging polarimeter, with high accuracy and narrow spatial and angular resolution, is the strongest candidate to sample cloud and aerosol properties at the level required for climate study. The Hyper-Angular Rainbow Polarimeter (HARP) is a wide field-of-view camera, designed and developed by J. Vanderlei Martins and the Laboratory for Aerosol and Cloud Optics (LACO) Group at UMBC to fill this role.

Over the past year, AirHARP, the HARP instrument adapted for aircraft, flew on two NASA research campaigns: the Lake Michigan Ozone Study (LMOS) and the Aerosol Characterization from Polarimeter and LIDAR (ACEPOL). The LMOS campaign was a joint NASA-NOAA-EPA effort to explore the connection between lake breezes and high ozone exceedance levels on the eastern coastline of Wisconsin in the summer months. AirHARP took data on many B-200 flights alongside the NASA Langley Research Center (LaRC) GeoTASO instrument, a trace gas experiment that measures ozone pre-cursors, such as NO₂, through the entire atmospheric column. Brent McBride, a Ph.D candidate in Martins’ group, operated AirHARP on-board the B-200 and led field operations on the ground throughout the campaign, while LACO group members engaged remotely from UMBC. While AirHARP does not have trace gas sensitivity, measurements of convective clouds and low aerosol levels over eastern Wisconsin will be compared to co-incident observations made by AERONET sun photometer sites and the Advanced Baseline Imager (ABI) on the GOES-R geosynchronous satellite.

Read more:   UMBC Atmospheric Scientists Use New Instrumentation

UMBC Physicists Discover Unexpected Effect of African

Wildfires on Climate

African Fires Effect Climate

Clouds play a prominent role in moderating Earth’s climate, but their role is still poorly understood. Generally, clouds cool the Earth by reflecting incoming sunlight back out into space. Reducing the clouds’ reflectivity—with a layer of pollution, for example—reduces the cooling effect. However, new research in Proceedings of the National Academy of Sciences by Zhibo Zhang, associate professor of atmospheric physics at UMBC, two of his students, and collaborators from University of Wyoming, University of Science and Technology of China, Universities Space Research Association, and University of Michigan adds another level of complexity to this model.

Every fall, fires race across central and southern Africa. Many are wildfires; others are intentionally set by humans to clear farmland. They create so much smoke that it’s clearly visible from space. Wind sweeps the smoke westward over the Atlantic Ocean, where it rises above the largest semi-permanent gathering of clouds in the world. For years, scientists believed that overall, the smoke diminishes the clouds’ cooling effect by absorbing light that the clouds beneath otherwise would reflect. The new study by Zhang and colleagues doesn’t dispute the existence of this effect, but introduces a new mechanism that counteracts it by making the clouds more reflective.

Read more:  UMBC Physicists’ New Discovery