Climatic Characteristic of Wire Icing in Hebei Province and Synoptic Process Analysis

doi:10.3969/j.issn.1673-7148.2012.01.002

Abstract：Using wire icing observation data of 20 stations in Hebei province from 1980 to 2009, the spatial and temporal distribution characteristic of wire icing are analyzed. The result shows that wire icing days on plain are more than in mountain, that wire icing days have obvious annual variation and present a descending trend. The wire icing days is obviously different in different seasons and wire icing days are the most in January. Maximum weight of wire icing is different in directions. Using conventional observa-tion data, 1°×1°NCEP data 6 h intervals, and hourly wind of Huanghua from 19 January 2010 to 20 January 2010, a synoptic process causing transmission line galloping is analyzed. The result shows that the wire icing process is caused by glaze on the background of ground cold air and low trough at 500 hPa and 700 hPa. Huanghua surface air temperature quickly dropped to near 0℃ on 20 January 2010 forcold air effect; and the temperature dropped gradually from zero to below zero at 850 hPa; the inversion layer occurs in the lower level of troposphere ; the vertical temperature structure is conducive to the formation of glaze. The intersection angle on galloping wire trend and wind direction is larger ; the galloping occurs after the higher wind speed appears.