北京地区闪电活动与气溶胶浓度的关系研究  

Analysis of potential effects of aerosol on lightning activity in Beijing metropolitan region

作　　者：孙萌宇 郄秀书[1,3] 刘冬霞 Yoav Yair[2] 夏祥鳌 袁善锋[1,3] 王东方 卢晶雨 Abhay Srivastava[1] Didier Ntwali SUN MengYu;QIE XiuShu;LIU DongXia;YOAV Yair;XIA XiangAo;YUAN ShanFeng;WANG DongFang;LU JingYu;ABHAY Srivastava;DIDIER Ntwali(Key Laboratory of Middle Atmosphere and Global Environment Observation,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;School of Sustainability,Interdisciplinary Center(IDC)Herzliya;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大气物理研究所中层大气与全球环境探测重点实验室,北京100029 [2]School of Sustainability,Interdisciplinary Center(IDC)Herzliya [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球物理学报》2020年第5期1766-1774,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金国际(地区)合作与交流项目(41761144074);国家自然科学基金面上项目(41875007)资助.

摘　　要：基于2015—2017年北京闪电定位网(BLNET)总闪资料与35个自动空气质量监测站PM 2.5数据,分析了北京地区(39.5°N—41.0°N,115.0°E—117.5°E)夏季(6—8月)闪电活动与PM 2.5的时空分布特征,同时针对117次雷暴天气,探讨了气溶胶浓度变化对闪电活动的可能影响.结果表明:PM 2.5浓度及总闪密度均呈现自西北向东南升高的空间分布特征.闪电峰值在污染背景下出现的时间(19∶00LT)晚于清洁背景下(15∶00LT)约4 h,且总闪百分比(~20%)可达清洁背景下(~9%)的两倍.对雷暴前1~4 h的PM 2.5浓度与时间窗(12∶00—22∶00LT)内总闪数目的中位数进行相关分析,发现PM 2.5浓度低于130μg·m-3时,PM 2.5与总闪数存在明显正相关,此时气溶胶可能通过影响云微物理过程进而影响雷暴的对流发展,增强闪电活动;PM 2.5大于150μg·m-3时,总闪数随PM 2.5浓度的增加呈减少趋势,可能的原因是高气溶胶浓度下地面太阳辐射显著下降,对流活动受到抑制,导致闪电活动减少.当PM 2.5浓度在130~150μg·m-3时,两者关系不明显.Based on the lightning data from Beijing Lightning Network(BLNET)and PM 2.5 data from 35 automatic air-monitoring stations,spatiotemporal distributions of total lightning activities and aerosols have been analyzed in Beijing(39.5°N—41.0°N,115.0°E—117.5°E).The response of lightning activities to aerosols is further investigated for a total of 117 thunderstorm days.The results indicated both spatial distributions of lightning density and pollutant demonstrated a gradual increase from northwest to southeast of Beijing metropolitan region.The peak lightning activity under relatively polluted condition occurred at 19∶00 LT(Local Time),4 hours later than that(15∶00LT)under relatively clean condition,higher aerosol concentration enhanced the percentage of total flashes by a factor of^2.Correlation analysis of PM 2.5 prior to the occurrence of thunderstorms to lightning density showed a significant positive correlation when PM 2.5 lower than 130μg·m-3.This is likely because aerosols enhanced lightning activities by affecting the convective activities through microphysical processes.On the contrary,as PM 2.5 exceeded 150μg·m-3,total flashes showed a negative relationship to PM 2.5.This might be attributed to lower solar radiation reaching the surface as a result of increasing aerosol loading.When PM 2.5 ranged from 130 and 150μg·m-3,the correlation between aerosols and lightning was very weak,which might be caused by the balance of microphysical and radiative effects of aerosols.

关 键 词：闪电活动 气溶胶 微物理作用 辐射效应 

分 类 号：P401[天文地球—大气物理学与大气环境]