SOURCES AND DISTRIBUTION OF SEA SALT AEROSOLS FROM THE TROPICS TO THE ARCTIC
Prof. Lyatt Jaeglé, Dept. of Atmospheric Sciences, University of Washington, Seattle
March 5, 2015, 1:30 pm, NASA Langley, Bldg 1250, Rm 116
Abstract:
In this work, I examine the global distribution of sea salt aerosols using in situ measurements of sea salt aerosols as well as remote sensing observations of aerosols optical depth (MODIS and AERONET) and aerosol extinction profiles (CALIPSO) together with the GEOS-Chem chemical transport model. A standard simulation with a canonical windspeed-dependent open ocean source of sea salt aerosols leads to a 50% underestimate of coarse mode sea salt aerosols over warm tropical waters and a factor of 2-3 overestimate at high wind speeds over cold waters in the midlatitude storm tracks. Including an empirical sea salt source function depending on both sea surface temperature and windspeed leads to improved agreement with in situ as well as remote sensing observations. I also show evidence for a missing source of fine mode sea salt aerosols during winter over the Arctic, based on in situ observations at Barrow and Alert, as well as satellite observations of enhanced aerosol extinction coefficients during winter by CALIOP. I demonstrate that the seasonality and spatial distribution of this missing source is consistent with a blowing snow source of fine mode sea salt aerosols over Arctic sea ice.
Note: The speaker will also touch on chemical forecasting in support of the WINTER 2015 aircraft campaign http://www.eol.ucar.edu/field_projects/winter.