能见度反演PM_(2.5)质量浓度方法的对比分析

Comparison Analysis of the Method of Using Visibility to Retrieve Concentration of PM_(2.5)

着眼于能见度对细颗粒物反演的准确表征,利用2013年6月1日—2014年2月28日成都市人民南路四段逐时 PM_(2.5)质量浓度以及大气能见度的监测数据,对比研究了基于能见度推算 PM_(2.5)质量浓度的直接与间接方法。前者利用幂函数直接构建能见度与 PM_(2.5)质量浓度的函数关系;后者则通过能见度对消光系数的求取,进一步以线性函数反演 PM_(2.5)质量浓度。分析结果表明:(1)2种方法均能较好地反演 PM_(2.5)质量浓度,反演结果与地面监测数据具有一致的统计特征;(2)相比基于能见度反演 PM_(2.5)质量浓度的直接方法,间接方法物理意义更为清晰,同时反演结果也更优。

To characterize precisely the usage of visibility to retrieve concentration of fine particles, a direct method andan indirect method were used to reckon PM2.5 mass concentration based on visibility in a comparative study with the hourlymonitoring data of PM2.5 mass concentration and atmospheric visibility at Section 4 of South People Road of Chengdu duringthe period from June 1, 2013 to Feb. 28, 2014 cited as subject. The former used power functions to directly develop afunctional relationship between visibility and PM2.5 mass concentration, while the latter first worked out extinction coeffi.cient by visibility and then used linear functions to retrieve PM2.5 mass concentration. Results show as follows： （1） Bothmethods can be used well to retrieve PM2.5 mass concentration and the retrieval matches the ground monitoring data quitewell in statistic feature; （2） Compared to the direct method of using visibility to retrieve PM2.5 mass concentration, the in.direct method is more explicit in physical significance and more accurate.