This project is an airborne field investigation of aerosol hazes in the arctic troposphere, which will include studies of the emission of dimethylsulfide (DMS) from the ocean and of the radiative and microphysical properties of stratus clouds. The project will make use of an instrumented C-131 aircraft owned by the University of Washington. The arctic summer haze phenomenon is considered to be important in a variety of arctic atmospheric processes. It affects the radiation budget directly by modifying the albedo and the thermal infra-red flux at cloud top levels, and indirectly through the modulating effects on cloud radiative properties by cloud condensation nuclei (CCN's). In particular, if it can be shown that DMS emissions control the local CCN concentrations, it may be possible to identify a biological control of the arctic marine stratus albedo. The project will make direct measurements of the distribution of arctic haze, and their chemical, microphysical, and optical properties. The concentration and fluxes of DMS from the Arctic Ocean will be measured, and their contribution to the local and global sulfur budgets will be estimated. The observations will provide data sets that will be used for the validation of satellite-derived cloud parameters.
