10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Mineral Dust Aerosol Measurements throughout the Global Free Troposphere and Implications for Cirrus Formation
KARL D. FROYD, Daniel Murphy, Gregory Schill, Agnieszka Kupc, Christina Williamson, Charles Brock, Pengfei Yu, Karen Rosenlof, Huisheng Bian, Mian Chin, Peter Colarco, NOAA ESRL and CIRES, University of Colorado Boulder
Abstract Number: 991 Working Group: Unraveling the Many Facets of Ice Nucleating Particles and Their Interactions with Clouds
Abstract Lab and field studies indicate that mineral dust particles are efficient ice nuclei, and recent airborne measurements confirm the dominant role of dust on cirrus cloud formation in the northern hemisphere. However, the net climate impact of mineral dust is not well constrained in part due to the lack of dust abundance measurements above the Earth’s surface. We present new airborne mineral dust measurements from the 2016-2017 NASA ATom (Atmospheric Tomography) campaigns that cover the entire Pacific and Atlantic basins from the boundary layer through the free troposphere. This global dataset fills a critical measurement gap for dust in the background upper troposphere. Measured concentrations are compared to global simulations of dust aerosol, with a focus on model accuracy at cirrus altitudes. We identify source contributions to the remote troposphere and examine mechanisms of vertical transport and removal. Using heterogeneous nucleation efficiencies from laboratory studies, we estimate that background dust particles can contribute to cirrus formation throughout wide regions of the global upper troposphere. In particular we explore north-south hemispheric gradients of dust aerosol and the implications for differences in cirrus properties.