Spatial and temporal characteristics of particulate matter in Beijing, China using the Empirical Mode Decomposition method
Spatial and temporal characteristics of particulate matter in Beijing, China using the Empirical Mode Decomposition method
复制标题
采用经验模态分解方法研究北京颗粒物时空特征
DOI：
10.1016/j.scitotenv.2013.04.005
复制
发表时间：
2013-08-01
影响因子：
9.8
通讯作者：
Pan, Yuepeng
中科院分区：
文献类型：
--
作者：
Hu, Maogui;Jia, Lin;Pan, Yuepeng
空气污染已经成为中国北京的一个严重问题。从2008年1月1日至2012年10月31日，在北京的27个站点收集了5年的每日PM10质量浓度测量值。采用一种新的聚类方法（核K均值）和一种新的周期和趋势分解方法（经验模态分解，EMD）对北京市PM10质量浓度的时空分布特征进行了研究。采用EMD方法对聚类中心的时间周期和趋势进行分解，这是一种不需要先验信息的自适应数据分析方法。PM10的日质量浓度变化很大，从5 μ g/m3到600 μ g/m3以上。所有的站点被划分为三个聚类的核K-均值方法，分别代表低，中，高污染站。第一个集群包含9个站点，主要位于北郊地区。第二个集群，其污染程度比第一个集群严重得多，包括13个站分布在城市和城郊地区。北京南部的污染程度比北方严重得多。第三组包含位于第二组台站之外的五个台站。在整个期间，三个集群的总下降幅度分别为19 μ g/m3、10 μ g/m3和4 μ g/m3。虽然PM10质量浓度的全球趋势总体上呈下降趋势，但各季节、各站点的趋势并不相同。夏季和冬季呈下降趋势，而春季近年来呈上升趋势。台站的趋势有单调递减、上升下降、下降上升下降、下降上升和上升五种类型。区域大气污染背景监测站密云水库的上升趋势表明，北京市的PM10质量浓度背景值呈上升趋势。(C)2013爱思唯尔有限公司版权所有。
Air pollution has become a serious problem in Beijing, China. Daily PM10 mass concentration measurements were collected at 27 stations in Beijing over a 5-year period from January 1, 2008 to October 31, 2012. We used a new clustering method (kernel K-means) and a new period and trend decomposition method (Empirical Mode Decomposition, EMD) to explore the spatial and temporal characteristics of the PM10 mass concentration in the City. The temporal period and trend of each cluster center were decomposed using the EMD method, which is an adaptive data analysis method that requires no prior information. The daily PM10 mass concentrations varied greatly from 5 mu g/m(3) to more than 600 mu g/m(3). All of the stations were partitioned into three clusters by the kernel K-means method, and which represent the low-, middle- and high-pollution stations, respectively. The first cluster contained nine stations, mainly located in the north suburban area. The second cluster, whose degree of pollution was much more serious than the first cluster, contained 13 stations distributed in urban and pen-urban areas. The pollution level in the southern part of Beijing was much more serious than in the northern part of the City. The third cluster contained five stations located outside the second-cluster stations. The total decreased amplitudes of the three clusters during the whole period were 19 mu g/m(3), 10 mu g/m(3) and 4 mu g/m(3), respectively. Although the global trend of the PM10 mass concentration decreased in general, it was not the same for each season and station. The trends in summer and winter declined, while in spring, it has been increasing in recent years. Five types of trends can be found for stations, including monotonic decreasing, rise fall, fall rise fall, fall rise and rise. The rising trend of the regional background air pollution monitoring station, Miyun-reservoir, indicates an increase in the City's background PM10 mass concentration. (C) 2013 Elsevier B.V. All rights reserved.