Sea salt aerosol production and bromine release: Role of snow on sea ice

Snow lying on sea ice could be a potentially important source of sea salt aerosol, as small snow particles, rich in salts, can be easily lifted into the air though blowing-snow events. Using a measured distribution of snow salinity on Antarctic sea ice and a blowing snow sublimation parameterization, we derive a method for estimating sea salt aerosol production, and bromine release, during blowing-snow events. Compared with sea salt aerosol production rates from the open ocean, we find that the aerosol production rate from snow can be more than an order of magnitude larger per unit area under typical weather conditions. The large sea ice cover may thus enhance the supply of sea salt to the polar lower atmosphere. This is consistent with observations of sea salt aerosol seasonality and with the ice-core record. This large emission of sea salt from snow also implies an additional tropospheric bromine source in these regions.