2010-2011年鞍山市能见度特征

利用2010年6月至2011年5月鞍山大气成分观测站的能见度资料，统计分析能见度与PM₁₀、PM_2.5、PM_1.0质量浓度、风速、降水强度和气溶胶光学厚度等气象要素的相关性。结果表明：鞍山市能见度月均值从8月份开始呈上升趋势，11月份达到峰值后开始显著下降，2月份达到最低值，自3月开始又出现较大幅度增长，进入夏季后略有下降；PM_2.5/PM₁₀、PM_1.0/PM₁₀比值与能见度呈反相关，能见度增大，PM_2.5/PM₁₀、PM_1.0/PM₁₀比值减小，且PM_1.0/PM₁₀的减小趋势更大，说明影响能见度的颗粒物以细粒子为主。平均风速与能见度变化趋势基本一致，与PM_2.5/PM₁₀、PM_1.0/PM₁₀的变化趋势呈反相关。随着雨强的增大，降水日能见度平均值随之减小，降水前一日和后一日的能见度平均值均大于降水日，且降水前一日及后一日的能见度改变量及改变率的绝对值随着降水强度的增加而增加。波长指数的变化说明影响鞍山能见度变化的污染物粒子整体较稳定，能见度与AOD成明显的反相关。

Characteristics of visibility over Anshan from 2010 to 2011

Based on the visibility data at atmospheric composition monitoring station of Anshan from June 2010 to May 2011, the relationship between visibility and meteorological elements such as mass concentrations of PM10, PM2.5, PM1.0, wind speed, precipitation intensity and aerosol optical depth (AOD) were analyzed. The results indicate that the monthly average visibility is in an increasing trend after August, reaches a peak in November and then drops significantly and gets the lowest value in February; it is in a substantial increase after March, while it is in a slight decrease in summer. The ratios of PM2.5 to PM10 and PM1.0 to PM10 have a negative correlation with the visibility, namely, the higher the visibility is, the lower two ratios are, and the decreasing trend of PM1.0/PM10 is significant. Thus, it suggests that particles affecting the visibility are mainly fine particles. The trends of the average wind speed and visibility are basically the same, while the trend of average wind is in a negative correlation with those of PM2.5/PM10 and PM1.0/PM10. The average visibility decreases with the increase of precipitation intensity. The average visibility in the days before the precipitation day and after the precipitation day is more than that in the precipitation day, and their change values and change rates increase with the increase of precipitation intensity. It can be seen by the change of the Angstrom exponent that pollutant particles impacting the visibility in Anshan are more stable as a whole. It is a significant negative correlation between visibility and AOD.