Current research activities of the Cloud and Aerosol Research Group (CARG) fall into two broad categories: atmospheric chemistry and aerosols, and cloud and precipitation studies.
Atmospheric Chemistry and Aerosols: These studies revolve around the unique data sets acquired by the CARG with its research aircraft, particularly those data obtained during the period 1999-2001 in FIRE-ACE/SHEBA, KWAJEX, SAFARI-2000 and CLAMS. The main goals of these studies include: determination of the origin and nature of aerosols and trace gases in different locales (e.g., the Arctic, the remote Pacific Ocean, Southern Africa, and the U.S.A.); and, evaluation of the effects of aerosols and trace gases on local, regional and global air quality and climate. Recent CARG publications, listed under each of the projects referred to above, provide detailed information on these studies.
The Convair-580 was in the Arctic in the spring of 1998 for the FIRE-ACE/SHEBA field study. In this large cooperative study, the Convair-580 flew twenty-three flights over the Arctic Ocean, many above a research ship frozen in the arctic ice, as well as over the DOE-ARM site in Barrow, Alaska. The in situ measurements obtained aboard the Convair-580 are being compared to remote sensing measurements from the ship, satellites, and the NASA ER-2 high-flying aircraft. Extensive measurements were also obtained from the Convair-580 on aerosols and cloud structures in the Arctic, and the reflectivity properties of various ice surfaces. These data are being used to increase understanding of aerosol-cloud-climate interactions in the Arctic.
Summer 2000 saw the Convair-580 in southern Africa for the SAFARI 2000 field project. Thirty-one research flights were carried out in five countries for the purpose of obtaining in situ measurements of aerosols and trace gases for comparison with remote sensing measurements from the NASA Terra satellite, ER-2 aircraft and ground-based instruments; to measure emissions from biomass burning and industries; to study regional hazes; and to investigate cloud structures off the west coast of southern Africa.
The CARG with the Convair-580 participated in the CLAMS field study off the U.S. East Coast in the summer of 2001. The principal goal was to obtain airborne measurements to validate NASA EOS-Terra data products. The CARG is analyzing measurements obtained aboard the Convair-580 to determine the contributions of vairous chemical species to aerosol radiative forcing on the U.S. East Coast.
Cloud and Precipitation Studies: The CARG has a long history of studies of clouds and precipitation on a variety of scales (see Publications). Current studies are concerned with tropical clouds and precipitation and with the representation of cloud microphysical processes leading to the formation of precipitation in mesoscale models.
During the 1999 KWAJEX field study in the Marshall Islands, three aircraft (including the UW Convair-580) obtained some comprehensive measurements on convective clouds in that region simultaneously with overpasses of the TRMM satellite and quantitative radar coverage. In addition to comparisons between the airborne in situ and remote sensing measurements, the CARG is analyzing these data to increase understanding of cloud structures and precipitation-producing mechanisms in tropical convection.
In the winter of 2000-2001, the CARG carried out the first phase of the IMPROVE field project. The goals of IMPROVE are to obtain measurements of the microphysical structures of precipitating systems within a dynamical framework for the purpose of improving the representation of cloud and precipitation processes in mesoscale models. IMPROVE-1 concentrated on frontal systems off the coast of Washington State. IMPROVE-2, carried out in the winter of 2001-2002, obtained measurements in orographic systems over the Oregon Cascades.
The comprehensive data sets obtained aboard the UW Convair-580 in the IMPROVE Frontal and Orographic Field Studies are being used to determine the growth processes leading to the formation of precipitation in these cloud systems. Thes data will then be used to evaluate and improve representation of cloud and precipitation processes in the MM5 mesoscale model.