Cloud Phase and the Surface Energy Balance of the Arctic; An Investigation of Mixed-Phase Clouds

• Main Author: Kripchak, Kristopher J.
• Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
• Format: Text
• Language: English
• Published: 2008
• Subjects: Meteorology; Geography; Thermodynamics; *CLOUDS; *METEOROLOGICAL DATA; *ARCTIC OCEAN; *SURFACE ENERGY; GROUND LEVEL; BALANCE; BUDGETS; HEIGHT; ARCTIC REGIONS; SEA ICE; HEAT; WIND VELOCITY; ICE; TEMPERATURE; SHEBA; POLAR METEOROLOGY; MIXED-PHASE CLOUDS; ARCTIC SURFACE ENERGY BALANCE; CLOUD PARAMETERIZATION; Arctic; Arctic Ocean; Sea ice; Surface Heat Budget of the Arctic Ocean
• Online Access: http://www.dtic.mil/docs/citations/ADA479968; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA479968

This study examines the phase relationship (liquid versus ice) in Arctic clouds Although it is recognized that clouds are fundamental components of the surface energy balance, the nature of Arctic cloud phase is poorly understood and may have important implications for feedbacks associated with the rapid disappearance of sea ice. This study uses the annual cycle of cloud, radiation, and meteorological measurements made as part of the Surface Heat Budget of the Arctic Ocean field program to derive empirical relationships for cloud liquid fraction as a function of observed variables. Relative to each other, single-layer liquid, ice, and mixed-phase clouds occurred 17.6%, 39.4%, and 42.9% of the time, respectively. The dominant role that mixed-phase clouds play in the surface energy balance of the Arctic was confirmed, emphasizing the need for their correct parameterization in models at all scales. A linear fit of liquid fraction to cloud base temperature between -36C and +2C predicts 35% of the fraction variance. Including the observed variables of cloud base height and surface wind speed as predictors predicts another 10%.