中国PM_(1)浓度时空特征及其与AOD的相关性分析(2014~2017年)

Spatial and Temporal Variations in PM_(1) Concentration and its Correlation with AOD in China from 2014 to 2017

整合2014~2017年全国PM_(1)监测站点数据,基于时间序列统计方法和空间系统聚类方法揭示了PM_(1)浓度的时空分布特征与演变规律.并结合MODIS遥感卫星气溶胶光学厚度(AOD)数据,分析了PM_(1)-AOD相关性的时空特征.结果显示,2014~2017年中国年均PM_(1)浓度逐年下降,四季PM_(1)浓度呈现“冬高夏低”的变化特征,月均PM_(1)浓度呈“U”型变化特征,在节假日前后PM_(1)浓度呈现“M”型变化特征,在一周中星期一和星期五PM_(1)浓度为高值点,星期日为低值点.基于空间系统聚类法将全国年均PM_(1)浓度分为7类区,全国PM_(1)浓度整体呈现“东高西低,北高南低”的空间分布格局,年均ρ(PM_(1))值在华中地区最高(54.59μg·m^(-3)),新青藏地区年均最低(11.37μg·m^(-3)).PM_(1)-AOD关系整体上呈正相关,华中地区相关系数最高(0.55),中南地区相关系数最低(0.36).

Based on the PM_(1)mass concentration data from all the air quality monitoring stations in China from 2014 to 2017,the temporal and spatial distribution characteristics of PM_(1)concentration were studied using the time series statistical and spatial hierarchical clustering methods,and the PM_(1)spatiotemporal evolution characteristics were revealed.Combined with AOD data of the MODIS remote-sensing satellite,the temporal and spatial variation in PM_(1)-AOD correlation was analyzed on a fine scale.The results showed that,from 2014 to 2017,the annual average PM_(1)concentration in China decreased yearly,the seasonal PM_(1)concentration showed the characteristics of“high in winter and low in summer,”and the monthly average PM_(1)concentration showed a“U”-shaped variation.An“M”-shaped PM_(1)variation pattern was presented before and after the holidays.Weekly variation showed that high PM_(1)values occurred on Mondays and Fridays,and low ones occurred on Sundays.Based on the spatial clustering method,the national average annual PM_(1)concentration in China was divided into seven categories,and the overall spatial distribution pattern was“high in the east and low in the west and high in the north and low in the south.”The highest and the lowest values of average PM_(1)concentration occurred in central China(54.59μg·m^(-3))and in Xinjiang-Qinghai-Xizang(11.37μg·m^(-3)),respectively.The PM_(1)-AOD relationship was positively correlated as a whole,the highest correlation coefficient was 0.55 in central China,and the lowest value was 0.36 in central and southern China.