AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Revising the Hygroscopicity of Inorganic Sea Spray Aerosol
PAUL ZIEGER, Olli Väisänen, Joel Corbin, Daniel Partridge, Sandra Bastelberger, Mehrnoush Mousavi-Fard, Caroline Leck, Evelyne Hamacher-Barth, Martin Gysel, Douglas Nilsson, Bernadette Rosati, Annele Virtanen, Ulrich Krieger, Ilona Riipinen, Matthew Salter, Stockholm University
Abstract Number: 43 Working Group: Aerosols, Clouds, and Climate
Abstract Sea spray aerosol (SSA) particles are hygroscopic - they readily exchange moisture with their surroundings, and therefore they change their equilibrium water content and radii under different atmospheric conditions. This influences their role in chemical reactions and the rate at which they uptake gases, as well as their light-scattering properties. To date, the growth of a SSA particle above 70% relative humidity has been considered to be very close to that of NaCl. However, using a laboratory sea spray chamber we have observed that inorganic SSA particles have a significantly lower hygroscopicity than NaCl. We report these measurements alongside simulations using large-scale models designed to test the sensitivity of radiative forcing to the hygroscopicity of SSA. These highlight that the lower hygroscopicity we observe has important implications for calculations of the radiative balance of the Earth given that most models currently use NaCl as a model for inorganic SSA hygroscopicity.