合肥市大气能见度变化特征及其影响因素

Characteristics of atmospheric visibility change and its influence factors in Hefei City,Anhui,China

利用2013年10月至2015年6月合肥市大气能见度的观测资料以及同期观测的气象要素和PM_(2.5)、PM_(10)浓度的资料,在全面分析大气能见度影响因子的基础上,重点探讨相对湿度(RH)、PM_(2.5)和PM_(10)浓度与大气能见度的关系.结果表明:研究期间,合肥市大气能见度与RH的相关性最高.当RH<60%时,随着RH的增大,PM_(2.5)和PM_(10)浓度与大气能见度的相关系数也逐渐增大;当RH>60%时,颗粒物浓度与大气能见度的相关系数呈递减趋势;当50%≤RH<60%时,PM_(2.5)和PM_(10)浓度与大气能见度的相关系数最大.RH较高时,大气能见度主要受RH影响,反之,颗粒物浓度对大气能见度的影响较大.当RH>70%时,大气能见度等值线变化幅度较大,RH对大气能见度的影响加强.根据RH、PM_(2.5)和PM_(10)浓度与大气能见度的拟合公式,非线性拟合模型优于多元线性拟合模型,可以较好地模拟大气能见度的变化规律.

Using the observation data of Hefei atmospheric visibility and meteorological elements and PM2.5 and PM10 concentrations at same period from October 2013 to June 2015, based on comprehensive analysis of the impact factors on atmospheric visibility, the relationships among the rela- tive humidity （RH）, PM2.5 and PMx0 concentrations and visibility were explored. The results showed that the correlation between RH and Hefei atmospheric visibility was most significant during the period of study. When RH〈60%, the coefficients of correlation between PM2.5 , PM10 concentra- tions and atmospheric visibility increased gradually with the increasing RH. When RH 〉 60%, the coefficients of correlation between the particles concentration in atmosphere and atmospheric visibili- ty showed a decreasing trend. When 50% ≤ RH 〈 60%, the coefficients of correlation between PM2.5, PMI0 concentrations and atmosphere visibility were higher. When RH was relatively higher, the atmospheric visibility was mainly affected by the relative humidity, on the contrary, the concentration of particles had a greater influence on the visibility. When RH〉70%, the change amplitude of contour line of atmospheric visibility was larger, and the impacts of RH on atmospheric visibility were intensified. According to the formula fitted by the data of RH, PM2.5, PM10 concentrations and atmospheric visibility, the nonlinear fitting model was better than multivariate linear fitting model in simulating the change of atmospheric visibility.