河北省雾的气候特征及趋势研究

Climatic Characteristics of Fog in Hebei Province and Trend Research

为了研究河北省雾的气候特征及变化趋势,用1965-2006年河北省49个代表站的气象观测资料,采用相关分析、趋势分析以及Mann-Kendall检验等统计方法,分析了雾的时空特征、日变化规律和长期变化趋势。结果发现:河北省年平均雾日数为15d,平原的雾日数多大于20d,高原、山区、丘陵的雾日一般小于10d;秋、冬季是雾的多发季节,11月雾发生频率最高为15.7%,除夏季外的其他季节,平原的雾日数一般最多;20世纪70年代初是河北省雾的明显转折点,雾日在1965-1971年处于偏少期,而1971年后经历了偏多偏少一偏多三个阶段;凌晨5时雾生的频率最高为22.2%,早上8时雾消的频率最高为18.8%,3h以内的短时雾最易出现;河北省雾日有一定的变化趋势,除了山前平原区站点多数为正趋势外,其他地形区测站则一般呈现为负趋势。

For studying climatic characteristics and change trend of fog in Hebei Province,based on the observational data from 49 meteorological stations in Hebei Province during 1965—2006,the temporal and spatial features of fog,diurnal variational law and the long-term variation trend are analyzed by using the correlation analysis,trend analysis and Mann-Kendall test methods.Results show that annual fog days are 15 d in Hebei Province,those in plain are more than 20 d,and in plateau,mountains and hills are less than 10 d.The fog-prone season is in autumn and winter,the 15.7%of fog frequency in November is the highest. Except summer,foggy days in plain are more than other topographic regions in general.The turning point of fog in Hebei Province is in the early 1970s.First,it is less from 1965 to 1971 then,after 1972 it experiences a more—less—more variational process.Frequency that fog occurs is the highest at 05：00 BT accounting for 22.2%,and frequency that fog dissipates is the highest at 08：00 BT accounting for 18.8%. The short-time fog within 3 hours occurs easily.Foggy days in Hebei Province hava a change trend,stations in piedmont plain show an upward trend mostly,but stations in other topographic regions show a downward trend commonly.