姚青,蔡子颖,刘敬乐,王晓佳,郝天依,韩素芹.气象条件对2009-2018年天津地区PM2.5质量浓度的影响[J].环境科学学报,2020,40(1):65-75
气象条件对2009-2018年天津地区PM2.5质量浓度的影响
- Effects of meteorological conditions on PM2.5 concentration in Tianjin from 2009 to 2018
- 基金项目：国家重点研发计划课题（No.2016YFC0203302）；国家自然科学基金（No.41771242，41675018）；中国气象局预报员专项（No.CMAYBY2019-007）
- 摘要：采用PM2.5质量浓度长期连续观测资料，结合地面气象资料和后向轨迹方法，分析2009-2018年天津地区PM2.5质量浓度的长期变化趋势，并探讨气象条件对其浓度变化的影响.结果表明，2013年受不利天气影响，PM2.5质量浓度达到近10 a来的峰值，其后逐年下降，2018年年均值降至52 μg·m-3，与优良天气和重污染及以上天气发生频率的年际变化趋势一致.相关性分析和主成分分析都表明相对湿度、风速和混合层厚度是影响天津地区，尤其是冬季PM2.5浓度的主要气象影响因素.不同季节下随着相对湿度增高，地面风速减小，混合层厚度降低，均有PM2.5污染加重的趋势，其中冬季差异最大，与该季节气象因素剧烈多变、静稳天气和寒潮交替发生有关.后向轨迹的聚类分析结果表明，途经天津偏南区域的短距离近地气流下PM2.5质量浓度较高，与该气流下易形成静稳天气有关，春季西北方向的长距离轨迹对应较高浓度的PM2.5则与沙尘天气有关.
- Abstract：Based on the long-term continuous observation data of PM2.5 mass concentration, combined with surface meteorological data and backward trajectory model, the long-term variation tendency of PM2.5 mass concentration in Tianjin from 2009 to 2018 was analyzed, and the influence of meteorological conditions on the concentration change was discussed. The results showed that the mass concentration of PM2.5 reached the peak value of nearly 10 years appeared in 2013, and then decreased year by year.The annual average value decreased to 52 μg·m-3 in 2018, which was consistent with the interannual variation trend of fine weather and heavy pollution weather. Correlation analysis and principal component analysis showed that relative humidity, wind speed and mixed layer thickness were the main meteorological factors affecting PM2.5 concentration in Tianjin, especially in winter. With the increase of relative humidity in different seasons.The surface wind speed and thickness of mixed layer decreased.There was a trend of PM2.5 pollution aggravating, among which the difference in winter was the greatest, which varied violently with the meteorological factors in this season. Steady weather was related to the alternation of cold waves. The results of cluster analysis of backward trajectory showed that the mass concentration of PM2.5was high under the short distance near-ground air flow south of Tianjin, which was related to the formation of static and stable weather under this air flow.The higher concentration of PM2.5 corresponding to the long distance trajectory in the northwest direction of spring was related to sand and dust weather.
