2017—2019年佛山市臭氧污染特征及其与气象条件的关系

Characteristics of ozone pollution in Foshan city and its relationship with meteorology during 2017-2019

利用2017—2019年佛山市环境空气监测站点监测的臭氧(O_(3))数据,结合同期气象观测资料,分析O_(3)污染的时空分布特征及其与气象条件的关系,并开展污染天气分型研究。结果显示,2017—2019年佛山市O_(3)污染呈恶化趋势,污染主要集中在9~10月,其次是5~6月;日变化显示出“单峰”型分布特征,一般在15时达到峰值;从空间上看,O_(3)污染主要集中在南部。O_(3)与日总辐射量、日最高气温、日均气温均呈正相关关系,与日均相对湿度、日总降雨量、降雨时长和风速均呈负相关关系;当日总辐射量高于10.1 MJ/m^(2)、日最高气温高于24.3℃,偏西风和风速不高于5 m/s时,有利于当地出现O_(3)污染;降雨发生和持续时间影响降雨对O_(3)污染缓解的效果,短时降雨和夜间降雨不能缓解O_(3)污染。诱发O_(3)污染的大气环流类型能分成8种,副高控制型、台风外围型、均压场型和弱高压脊型诱发的O_(3)污染次数最多、污染浓度最高;不同季节诱发O_(3)污染的大气环流类型不同,夏季和冬季的污染大气环流类型相对单一,春季和秋季的污染大气环流类型相对复杂。

This study analyzes the pollution properties of ozone(O_(3))and their relationship with meteorological factors,and classifies the synoptic weather on O_(3) pollution using observed O_(3) and relevant meteorological data in Foshan city during 2017-2019.The results show that the O_(3) pollution was deteriorating,generally with the summit in September and October,followed by May to June.The diurnal variation of O_(3) shows a“single peak”distribution characteristic,which generally reaches its peak at 15:00.The spatial distribution indicates that the O_(3) pollution is relatively heavy in southern Foshan.Ozone(O_(3))shows a positive correlation with the total daily radiation,the maximum daily temperature,and the daily averaged temperature;in contrast,a negative correlation with the daily averaged relative humidity,the daily accumulated precipitation,the rainfall duration,and the wind speed.The O_(3) pollution preferentially occurs when the total radiation amount is higher than 10.1 MJ/m^(2),the maximum daily temperature is higher than 24.3℃,west wind and the wind speed is lower than 5 m/s.The impacts of rainfall on O_(3) pollution depend on the duration and occurrence time of rainfall;short-term rainfall and rainfall at night cannot mitigate O_(3) pollution.Among the 8 patterns of the synoptic systems inducing O_(3) pollution,the subtropical high,the typhoon periphery,the uniform pressure field,and the week ridge of high pressure induce the most O_(3) pollution events and the highest pollution concentration in Foshan.It is aware that the dominant synoptic weather patterns inducing O_(3) pollution vary seasonally:only a few synoptic patterns induce O_(3) pollution in summer and winter;while all patterns can worsen O_(3) pollution in spring and autumn.