The Aerosol Cloud Meteorology Interactions Over the Western Atlantic Experiment (ACTIVATE) gathered data on the relationships between aerosols and clouds to expand understanding of different cloud properties and their impact on climate and weather.
Two aircraft were deployed throughout the campaign—the King Air and the HU-25 Falcon—to conduct statistical surveys over the northwestern Atlantic Ocean. The King Air was equipped with remote sensing instrumentation and dropsondes, while the HU-25 was equipped with an in situ payload for measurements of aerosols, cloud properties, trace gases, and meteorological parameters.
The dual aircraft approach allowed for a more comprehensive characterization of aerosol and cloud properties in a single atmospheric column at the same time. Both aircraft operated on the same flight path but flew at different altitudes: the King Air flew at about 9 km, and the HU-25 flew in the lower troposphere (below 3 km), where boundary layer clouds evolve.
ACTIVATE was a six-deployment Earth Venture Suborbital-3 (EVS-3) mission that comprised 150 coordinated flights over the western North Atlantic from 2020-2022. The science observing strategy targeted the shallow cumulus cloud regime, and the team collected sufficient statistics over a broad range of aerosol and weather conditions to enable robust characterization of aerosol-cloud-meteorology interactions.
This strategy was implemented by two nominal flight patterns: statistical survey and process study. The statistical survey pattern involved close coordination between the remote sensing and in situ aircraft to conduct near-coincident sampling at and below the cloud base, as well as above and within cloud tops. The process study pattern involved extensive vertical profiling to characterize the target cloud and surrounding aerosol and meteorological conditions.
The final half of the sixth deployment included a joint plane transit on May 31, 2022, from NASA’s Langley Research Center to L.F. Wade International Airport in St. George's Parish, Bermuda. Deploying out of Bermuda allowed ACTIVATE researchers to fly farther out over the Atlantic Ocean and thereby take measurements that were less affected by emissions from U.S. East Coast cities and by differences in sea surface temperatures caused by the Gulf Stream. Some of the flights included surface monitor work conducted in coordination with the NSF-funded BLEACH project focusing on halogen chemistry.
During the Bermuda campaign, there was evidence of African dust in the region, which the airborne team sampled. Another highlight of the deployment was a joint research flight synchronized with a CALIPSO satellite overpass in conditions that were ideal for inter-comparisons of data.
The ACTIVATE team is now focusing on analysis of the full three years of archived data.
