山西省1981—2010年大气能见度变化趋势研究

Analysis of Visibility Variations in Shanxi from 1981 to 2010

采用线性倾向率以及气候变化趋势检验的方法分析了近30年山西能见度的变化特征,同时应用平均值法、累积百分率分析法和Ridit分析法,利用山西省109个地面站的大气能见度资料及相关的地面气象常规资料(1981—2010年)对能见度变化趋势进行分析,发现山西11个城市大气能见度空间分布呈现自西北向东南递增的趋势;30年来由于空气污染,11个城市的大气能见度均显著下降,山西省1981—2010年年、春、夏、秋、冬能见度年平均值变化一直处于下降趋势,线性倾向率与年变化趋势系数均为负,四季中夏季的下降趋势最明显,高于年总下降趋势,春季的下降趋势最小,年总下降趋势高于春、秋、冬季的下降趋势。能见度的4个季节的差异呈减小趋势,能见度下降最明显的为夏季。从山西省1981—2010年平均能见度的月和季变化可以看出,能见度有明显的月和季变化特征。能见度的月变化呈多峰分布,3个峰值分别出现在2、6、9月,最大值出现在6月;能见度的季变化呈单峰分布,夏季最高、秋季次之、冬季最低。

Visibility data from 11 cities＇ meteorological stations in Shanxi Province were examined. The trendsof visibility from 1981 to 2010 were analyzed by using three different statistical methods： cumulativepercentiles, Ridit analysis and frequency of very good visibility. The results showed that from north to south ofShanxi Province, the distribution character of visibility was from high to low. The visibility of the 11 citiesdeclined notably over the past 30 years, and the largest range of visibility declining was in summer. Theturning period of visibility change took place during 1981-2002, and both the visibility and very good visibilityfrequency of the 11 cities decreased rapidly at that time. This was consistent with the economic development.During 2006-2009, the visibility had a rising trend. During 1981-2010, we found that visibility had obviouslymonthly and seasonal variation characteristics. Three peaks appeared in February, June and September,respectively, the maximum appeared in June. Seasonal change was a unimodal distribution.