1961—2013年辽宁地区冰冻天气时空分布特征

Temporal and spatial distribution of freezing weather from 1961 to 2013 in Liaoning province

利用1961—2013年辽宁省55个气象站的雾凇和雨凇观测资料,采用线性趋势、经验正交函数(EOF)和Morlet小波法等方法,分析了辽宁省雨淞和雾淞的时空分布特征。结果表明:1961—2013年辽宁雾凇日数明显多于雨凇日数,雨淞和雾淞同时出现的次数较少;雾凇日数具有明显的经向分布,雨凇日数具有明显的纬向分布。辽宁省大部地区雾凇日数呈明显减少的趋势,气候倾向率为30 d/10 a;而雨凇日数呈缓慢增加的趋势,气候倾向率为2 d/10 a;辽宁省雨淞和雾淞日数的空间异常结构均表现为一致性,EOF第一模态对应的时间系数变化趋势与雨淞、雾淞的时间分布特征一致。

Based on daily rime and glaze data at 55 weather stations in Liaoning province from 1961 to 2013,temporal and spatial distributions of rime days and glaze days were analyzed by methods of a linear trend,an EOF（ empirical orthogonal function） and a Morlet wavelet transform. The results showthat number of rime days is far more than that of glaze days,and frequency that rime and glaze occur simultaneously in a same day is low. Distribution of rime day is significantly longitudinal,while that of glaze day is latitudinal. Number of rime day is in a significantly decreasing trend with 30 days per decade in most areas of Liaoning province,while that of glaze day is in a gradually increasing trend with 2 days per decade. Spatial difference of rime day and glaze day both are consistent,and trend of time coefficient corresponding to the first mode of EOF is consistent with temporal distribution of glaze day and rime day.