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Local ice formation via liquid water growth in slowly ascending humid aerosol/liquid water layers observed with ground‐based lidars and radiosondes
Author(s) -
Wu Cheng,
Yi Fan
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd025765
Subject(s) - radiosonde , aerosol , atmospheric sciences , liquid water , environmental science , drop (telecommunication) , ice crystals , liquid water content , materials science , meteorology , geology , geography , cloud computing , earth science , telecommunications , computer science , operating system
Observations with lidars at Wuhan (30.5°N, 114.4°E), China, from 2010 to 2013 captured nine cases of slowly ascending humid aerosol/liquid water layers that occurred at altitudes of ~2–4 km in winter. Each of them was almost transparent initially with the backscatter ratio far less than 7.0 and depolarization ratio less than 0.03. With a slow ascent, the layer developed into a nearly opaque liquid cloud layer and then ice crystals abruptly formed at the upper edge of the cloud layer with very high liquid water content. The ice crystals likely came from water drop freezing. The freezing temperatures estimated from radiosonde measurements were −3 to −8°C. For two available long‐lived (>16 h) cases, the layer was observed to always lie just below an inversion layer. The ice development on the layer was followed by rainfall.