Abstract View
The Clear Sky Bias in Atmospheric Chemistry
ANNMARIE CARLTON, University of California, Irvine
Abstract Number: 128
Working Group: Invited by Conference Chair
Abstract
Liquid water is a critically important constituent of the troposphere. At any given time, more than half of Earth’s surface is covered by visible clouds, and cloudiness changes in a changing climate. Aerosol-cloud interactions are critical to processes that govern air quality, radiative forcing and regional hydrological cycling. Yet, persistent uncertainties in these processes limit predictive skill of atmospheric models across scales. Clouds are primary drivers of vertical transport in the atmosphere, moving trace species from the polluted boundary layer to the Free Troposphere. Partitioning of water-soluble gases and their condensed phase chemistry generates particle mass aloft, such as sulfate, water-soluble organic carbon, and organosulfur compounds. Key uncertainties are related to the chemical nature of hygroscopic aerosol that become cloud condensation nuclei (CCN) and their interaction with organic species. Gas-to-droplet or gas-to-aqueous aerosol partitioning of organic compounds is affected by the intrinsic chemical properties of the organic species in addition to the pre-existing condensed phase. Environmentally relevant conditions for most atmospheric aerosol are non-ideal and chemical theory is incomplete. For example, salt identity and concentration, in addition to aerosol phase state, can dramatically affect organic gas miscibility for many compounds, in particular when ionic strength and salt molality are outside the bounds of limiting laws. The effects of inorganic salts on the fate and transport of organic species in the atmosphere are discussed.