Ice particle habits in Arctic clouds

• Main Authors: A. V. Korolev, G. A. Isaac, J. Hallett
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1999
• Subjects: Arctic; Climate change
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.474.4691; http://airs-icing.org/publications/Korolev - IcePaperGRL1.pdf

Abstract. Radiative properties of ice crystals in the atmosphere depend for a given mass on the crystal shape. Climate change predictions, precipitation growth prediction for weather forecasting, and remote sensing retrievals for nowcasting, require assumptions to be made about such shapes which also determine particle density and terminal fall velocity. Idealized crystal shapes as columns, needles, plates and dendrites have been used to compute the role of crystals in the earth radiation budget. Using new technology imaging instrumentation with a resolution of 2-3 µm, recent observations in Arctic clouds have shown that such pristine habits only describe approximately 3 % of the particles. The measurements were made from an aircraft during April 98 and cover a temperature range of 0 oC to-45 oC. Boundary layer, multi-layer and cirrus clouds were examined. The commonly observed irregularly shaped particles either consisted of faceted polycrystalline particles or sublimating (solid to vapor) ice particles with smooth curving sides and edges. Since climate warming is now predicted to be largest in the Arctic, and cloud properties significantly affect the radiation balance, it will be necessary to consider the effects of non-pristine ice particle habits in such calculations and predictions.