Sea-spray particles cause freezing in clouds

Ice clouds in marine regions at high latitudes might form in warmer and drier air than was previously believed because of freezing induced by airborne particles that contain organic materials from ocean surface waters. See Letter p.234 Ice-forming 'biological' particles in the marine atmosphere The presence of ice in clouds can have an influence on cloud lifetime and radiative properties. It remains uncertain to what extent sea spray may act as ice nucleating particles that facilitate the formation of ice in clouds. This study finds that organic material at the sea-air interface, probably derived from phytoplankton cell exudates, nucleates ice under conditions relevant for ice cloud formation in the atmospheric environment. Model simulations suggest that marine organic material may be an important source of ice nucleating particles in remote marine environments such as the Southern Ocean.
Author(s): Lynn M. Russell [sup.1] Author Affiliations: (1) Lynn M. Russell is at the Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0221, USA., The oceans [...]