【摘要】 用累积百分率分析法、Ridit分析法和“非常好”能见度出现频率分析法分别对河北省11个城市1960～2002年的大气能见度进行了研究和分析。结果表明,河北省11个城市大气能见度的地理分布大致呈现自北向南其值由高到低的势态;43年来由于空气污染,11个城市的大气能见度均显著下降,夏季能见度下降的幅度最大。1979～1981年为大气能见度变化的转折期,在此期间11个城市的能见度迅速降低、“非常好”能见度出现频率很快下降。1998～2002年,石家庄、承德、秦皇岛、唐山、邯郸的大气能见度出现上升趋势,沧州、邢台、廊坊、张家口的大气能见度维持不变,保定和衡水的大气能见度继续下降。更多还原

【Abstract】 Visibility data have been examined for 11 cities’ meteorological stations in Hebei Province. The trends of visibility from 1960 to 2002 have been analyzed by using three different statistical methods: cumulative percentiles, Ridit analysis, and frequency of “very good” visibility. The result shows that from north to south of Hebei Province, the distribution character of visibility is from high to low. The visibility of 11 cities has declined notably over the past 43 years, and the largest range of visibility declining is in summer. The turning period of visibility change took place during 1979-1981, and both the visibility and “very good visibility” frequency of the 11 cities decreased rapidly at that time. This is consistent with the economic development. During 1998-2002, the visibility had a rising trend in Shijiazhuang, Chengde, Qinhuangdao, Tangshan and Handan, and remained unchanged in Cangzhou, Xingtai, Langfang and Zhangjiakou, but declined continually in Baoding and Hengshui.更多还原