Seminar Ozean, Eis, Atmosphäre

Date: 25.11.2003

Speaker: Dr. Andrew Rankin (BAS)

Frost flowers are delicate ice crystals that form on the surface of sea ice as it freezes. Evidence from the chemical signature of frost flowers, remote sensing and back trajectories suggest that the majority of sea salt in the Antarctic snowpack is derived from frost flowers rather than open water. Strong sea-salt signals in ice cores have hitherto been attributed to more efficient aerosol production from open water due to stormier weather. However, they may instead be related to the increased formation of new sea ice and associated frost flowers. Frost flowers may be important in other fields - laboratory experiments passing ozone over frost flowers grown from sodium bromide solution demonstrate the production of a photolysable compound that can destroy ozone, suggesting that frost flowers may also be a source of the bromine implicated in polar tropospheric ozone depletion events.