华东地区能见度时空变化特征及影响因子分析

为探究华东地区能见度变化情况，利用1973—2020年的能见度数据、2014—2019年的气象要素和污染物浓度数据，采用趋势分析、经验正交函数(Empirical Orthogonal Function, EOF)分解、相关分析的方法，分析了能见度时空变化特征及影响因子。结果表明：(1)1973—2020年能见度呈显著(p<0.01)下降趋势，变化倾向率为-1.315 km/10a,季节之间存在差异，夏、秋季能见度下降速率较大分别为1.681 km/10a、1.443 km/10a;冬、春季下降幅度相对较小分别为1.092 km/10a、1.091 km/10a。其中，1973—2012年能见度呈显著(p<0.01)下降趋势，变化倾向率为-1.204 km/10a, 2013—2020年能见度呈不显著(p>0.05)增加趋势，变化倾向率为2.229 km/10a,近8年(2013—2020年)来能见度存在明显改善。(2)华东地区南部、北部能见度较好，中部能见度较差。EOF分解第1模态表明华东地区能见度整体变化趋势一致，第2模态具有明显的区域差异。(3)能见度与相对湿度...

Spatial-Temporal Variation of Visibility and Its Influencing Factors in East China

In order to explore the changes in visibility in East China, using visibility data from 1973 to 2020, meteorological elements and pollutant concentration data from 2014 to 2019, the temporal and spatial variation characteristics and influencing factors of visibility are analyzed by using trend analysis, empirical orthogonal function (EOF) decomposition, and correlation analysis. The results show that from 1973 to 2020, the visibility shows a significant (p<0.01) decreasing trend, and the trend rate of change is -1.315 km/10a. There are differences between seasons. The decreasing rates of visibility in summer and autumn are 1.681 km/10a and 1.443 km/10a, respectively. The decrease rates in winter and spring are 1.092 km/10a and 1.091 km/10a, respectively. The visibility shows a significant (p<0.01) decreasing trend from 1973 to 2012, and the change tendency rate is -1.204 km/10a. The visibility shows an insignificant (p>0.05) increasing trend during 2013-2020, and the change tendency rate is 2.229 km/10a. Visibility has improved significantly in the past eight years (2013-2020). Visibility is better in the south and north of East China but poorer in the middle. The first mode of EOF decomposition shows that the overall change trend of visibility in East China is consistent. The second mode has obvious regional differences. Visibility is significantly negatively correlated with relative humidity, PM_2.5, PM₁₀, SO₂, and NO₂, and positively correlated with O₃ mass concentration. Relative humidity is the most important factor affecting visibility reduction, followed by PM_2.5 mass concentration. The relationship between temperature and pressure, and visibility is strong uncertainty.