两次高压电线积冰过程气象成因分析

对2008年2月25—26日和2009年1月5—9日湖北省500 kV高压输电线路张恩1回线307号杆塔采集到的两次积冰过程进行分析,结果表明:两次积冰过程具有相似的环流形势即500 hPa中高纬为两槽一脊。低纬度地区有短波槽活动,700 hPa低空急流明显,地面处于冷锋前。低空急流、地面冷锋均有利于冰冻雨雪天气发生,且积冰过程中均有良好的温湿条件,并都伴有降水发生,这些条件都为积冰形成提供了良好的动力及热力条件。而2008年积冰过程大气温度垂直结构存在暖层,是造成两次过程形成机制不同的原因之一。

Analysis of the causes for two high-voltage wire icing cases

Two icing cases happened on 500-kV high voltage transmission lines in Hubei Province during February 25-26, 2008 and January 5-9, 2009. Study showed that the circulation patterns in both cases are similar: there were two troughs and a ridge in high latitudes, a short-wave trough in low latitudes at 500 hPa, a low-level jet at 700 hPa, and a surface cold front. The low-level jet and surface cold front were conducive to the occurrence of freezing rain and snows. Also, icing processes involved precipitation, certain temperature and humidity conditions. These conditions provided good potential and thermal conditions for the formation of icing. A warm layer existed in the vertical temperature structure of the atmosphere in the 2008 case, but not in the 2009 case. This resulted in the difference in formation mechanisms of the two cases.