2008~2017年北京市PM_(2.5)周期性变化特征与影响机制  

Multi-time scale variations of the PM_(2.5) in Beijing and its key mechanisms during 2008 to 2017

作　　者：郭滢超 权建农 潘昱冰 蒲维维 冯琎 赵秀娟 袁铁[1] GUO Ying-chao;QUAN Jian-nong;PAN Yu-bing;PU Wei-wei;FENG Jin;ZHAO Xiu-juan;YUAN Tie(College of Atmospheric Science,Lanzhou University,Lanzhou 730000,China;Beijing Institute of Urban Meteorology,Beijing 100089,China;Environmental Meteorology Forecast Center of Beijing-Tianjin-Hebei,Beijing 100089,China)

机构地区：[1]兰州大学大气科学学院,甘肃兰州730000 [2]北京城市气象研究院,北京100089 [3]京津冀环境预报预警中心,北京100089

出　　处：《中国环境科学》2022年第3期1013-1021,共9页China Environmental Science

基　　金：国家重点研发计划(2018YFF0300101-2)。

摘　　要：利用Morlet小波方法分析北京市2008~2017年PM_(2.5)资料,结果表明,北京市PM_(2.5)浓度存在显著的日变化、周变化、以及季节和年变化周期性特征,并且秋冬季的周期性特征显著高于春夏季.结合气象资料,包括水平风速、大气边界层高度、以及大气稳定度指数等,分析PM_(2.5)不同周期性变化对应的主要影响机制表明:大气边界层过程是PM_(2.5)日变化的主要影响机制,导致PM_(2.5)浓度白天低、夜间高.秋冬季PM_(2.5)日变化幅度高于春夏季;天气过程是PM_(2.5)周变化的主要机制,PM_(2.5)浓度与天气变化过程带来的风速变化和边界层高度呈强反相关关系;PM_(2.5)的季节变化与大气扩散能力的季节变化密切相关,秋冬季减弱的大气扩散能力加速了PM_(2.5)在近地面累积,春夏季则相反.The variation of PM_(2.5)concentration during 2008 to 2017 in Beijing urban area was investigated collectively using the Morlet wavelet method to understand the multi-time scale oscillations of PM_(2.5). PM_(2.5)in Beijing owned clear temporal variations(on diurnal, week, to seasonal timescales), especially in autumn and winter. Further analyses of wind, planetary boundary layer(PBL),and air stagnation index(ASI) revealed the mechanisms that affect multi-scale temporal oscillations of the PM_(2.5). The analyses indicated: the diurnal PM_(2.5)variation was closely related to boundary layer process with high concentration at nighttime and low concentration at daytime. The diurnal variations of PM_(2.5)in autumn and winter was higher than that in spring and summer;the weekly PM_(2.5)variation was closely related to synoptic process, and the PM_(2.5)concentration was anti-correlated to wind speed and PBL height;the seasonal variation of PM_(2.5)was caused dominantly by the seasonal variation of atmospheric diffusion capacity with high concentration in autumn and winter and low concentration in summer and spring.

关 键 词：MORLET小波分析 北京 PM_(2.5)周期性变化 气象机制 

分 类 号：X513[环境科学与工程—环境工程]