Bridging Gas And Aerosol Properties Between Northeast U.S. And Bermuda: Analysis Of Eight Transit Flights
Presenter: Cassidy Soloff1
Co-Author(s): Taiwo Ajayi, Yonghoon Choi, Ewan C. Crosbie, Joshua P. DiGangi, Glenn S. Diskin, Marta A. Fenn, Richard A. Ferrare, Francesca Gallo, Johnathan W. Hair, Miguel Ricardo A. Hilario1, Simon Kirschler, Richard H. Moore, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Christiane Voigt, Edward L. Winstead, Luke D. Ziemba
Advisor(s): Armin Sorooshian
1Department of Hydrology and Atmospheric Sciences, University of Arizona
The western North Atlantic Ocean is strongly influenced by continental outflow, making it the ideal region to study the atmospheric transition from a polluted coastline to the marine environment. Utilizing eight transit flights between NASA Langley Research Center (LaRC) in Hampton, VA and the remote island of Bermuda from NASA’s Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE), we examine the evolution of trace gas and aerosol properties off the coast of the U.S. The first pair of flights flew along the stream of continental outflow, while the other flights captured a mix of marine and continental air mass sources. For measurements within the boundary layer (BL), there was an offshore decline in particle N<100 nm, N>100 nm, CH4, CO, and CO2 concentrations, all leveling off around ~900 km offshore from LaRC. These trends are strongest for the first pair of flights. In the BL, offshore declines in organic mass fraction and increases in sulfate mass fraction and oxidized organics coincide with increasing hygroscopicity based on f(RH) measurements. Free troposphere measurements show a decline in N<100 nm but other free troposphere measurements are more variable when compared to the prominent offshore gradients seen in the BL. Pollution layers exist in the free troposphere, such as smoke plumes, that can potentially entrain into the BL. This work provides detailed case studies with a broad set of high-resolution measurements to further our understanding of the transition between continental and marine environments.