闪电活动对近地面大气中氮氧化物、臭氧及颗粒物的影响
发布时间：2018-08-15 11:25
【摘要】：闪电是一种常见的自然现象,地球上每秒约有30~100次闪电发生。闪电作为最常见的气象灾害之一,直接威胁人类的生命和财产安全。同时,闪电的高温、高压等特点能够迅速引起多种大气化学反应,进而对大气化学组分及大气环境质量乃至气候产生影响。闪电不仅是大气中氮氧化物(NO_x)主要的自然源之一,也可以通过直接与间接的方式对大气臭氧(O_3)浓度产生影响,而O_3浓度又直接影响大气的氧化能力。此外,闪电也可能诱导大气中新颗粒物的生成。然而,综合研究闪电活动及其相关气象条件对近地面大气NO_x及O_3浓度的影响以及闪电过程中颗粒物浓度及其化学组分变化的研究目前在我国还未见报道。本研究主要基于香港地区闪电定位系统所获取的闪电数据、香港空气质量监测数据、气象数据以及地形数据,探讨香港地区的地闪活动时空分布特征以及闪电活动对近地面大气中NO_x及O_3的影响;同时基于在广州从化开展的人工引雷实验,对闪电发生前后NO,O_3及亚微米级细粒子浓度和化学组成进行了观测,探讨其可能的大气化学机制。本研究的开展一方面对防雷减灾以及雷雨季节大气环境质量的评估具有一定的指导意义,同时也为闪电的大气化学效应及其影响机制的深入研究提供了新的方法和一定的数据基础。具体研究内容及相关研究成果主要包括以下几个方面:(1)香港地区地闪活动时空分布特征及其影响因素:通过对香港地区2006~2012年闪电定位数据、气象参数和海拔高度等相关数据的统计及相关性分析,发现香港地区2006~2012年间地闪发生次数最多的为2010年,最少为2011年;就月际变化而言,地闪活动的发生主要集中在4~9月;正、负地闪回击次数的日变化峰值则均出现在凌晨1点。地闪活动的时间变化特征主要受到天气和气候因素以及海陆热力差异的综合影响。在空间分布上,西部地区的正地闪回击密度明显高于东部,而负地闪回击密度的高值中心则主要集中在海拔较高的山区。正、负地闪回击密度均随海拔的升高而有所增加。(2)香港地区地闪活动及相关气象条件对近地面NO_x及O_3浓度的影响:选择香港地区三个代表不同土地利用类型的研究站点(郊区站塔门、新市镇站东涌及市区站葵涌),主要采用主成分分析/绝对主成分得分方法(PCA/APCS)结合多元线性回归(MLR)模型对NO_x和O_3浓度、闪电定位数据及相关气象数据进行了分析。发现三个站点的NO_x浓度在闪电日均有一定增加,增长幅度在4.1%~20.5%之间;而O_3浓度则均在闪电日显著减少,减少幅度为26.5%~44.4%。对相关影响因子的研究结果表明,土地利用类型、闪电活动(如:地闪回击频率和平均峰值电流)及其相关气象条件(如:风向、风速、降水、温度、相对湿度、云量和对流有效位能)等均对近地面NO_x及O_3浓度的变化具有不同程度的影响。(3)基于人工引雷技术对闪电大气化学效应的验证:通过对2014年8月19日进行的五次成功人工引雷前后NO,O_3及亚微米级细粒子浓度变化的观测,发现NO在引雷前半小时平均浓度为0.4 ppbv,第一次人工引雷成功后迅速升高,峰值浓度达到220.5 ppbv,其余四次引雷后NO浓度也都有不同程度的升高。O_3浓度在人工引雷前有所增加,而在第一次引雷成功后迅速降低至谷值16.9 ppbv。O_3浓度在引雷前的增加可能与周边自然闪电电晕放电所产生的O_3以及下沉气流所携带的浓度相对较高的O_3有关,引雷后O_3浓度的下降则可能是由闪电快速产生的NO对O_3的滴定作用引起的。此外,亚微米级细粒子浓度在引雷成功后出现快速增长的现象,这可能是由于闪电过程有利于离子诱导成核产生新粒子导致的。(4)基于单颗粒气溶胶质谱仪(SPAMS)对人工引雷前后颗粒物化学组分的初步研究:人工引雷前、中、后三个阶段的正、负离子平均谱图显示,引雷过程中颗粒物的正、负离子平均质谱图与引雷前相似,最大的差异在于出现了铁离子的特征峰。对含铁颗粒的统计结果表明,含铁颗粒数在第一次引雷成功后的几分钟里显著高于其他时间,含铁颗粒数峰值的出现略晚于NO峰值浓度的出现时间。由于引雷过程中的铁离子主要由人工触发闪电导致火箭导线熔化产生,因此引雷过程中含铁颗粒数量及占比的显著增加从侧面反映出闪电通道中化学组分的改变会对颗粒物化学组分产生一定影响。对含氮颗粒的分析结果则显示,闪电过程可能导致大气颗粒物中硝酸根的增加。
[Abstract]:Lightning is a common natural phenomenon. Lightning occurs about 30-100 times per second on the earth. Lightning, as one of the most common meteorological disasters, directly threatens the safety of human life and property. Lightning is not only one of the major natural sources of nitrogen oxides (NO_x) in the atmosphere, but also directly and indirectly affects the concentration of atmospheric ozone (O_3). In addition, lightning may also induce the formation of new particles in the atmosphere. However, a comprehensive study of flash The effects of electrical activities and related meteorological conditions on the concentrations of NO_x and O_3 in the near-surface atmosphere and the changes of particulate matter concentrations and their chemical components during lightning have not been reported in China. Based on the topographic data, the temporal and spatial distribution characteristics of the ground lightning activity in Hong Kong and the influence of lightning on NO_x and O_3 in the near-surface atmosphere are discussed. The concentration and chemical composition of NO, O_3 and submicron fine particles before and after lightning occurrence are observed, and the possible atmospheric chemistry is discussed. On the one hand, this study has a certain guiding significance for lightning protection and disaster mitigation as well as the assessment of atmospheric environmental quality in thunderstorm season, on the other hand, it also provides a new method and a certain data basis for the in-depth study of lightning atmospheric chemical effect and its impact mechanism. Several aspects: (1) Spatial and temporal distribution characteristics of ground lightning activity in Hong Kong and its influencing factors: Through statistical analysis and correlation analysis of lightning location data, meteorological parameters and altitude data in Hong Kong from 2006 to 2012, it is found that the most frequent occurrences of ground lightning in Hong Kong from 2006 to 2012 are in 2010, at least in 2011; and on the basis of monthly variation. In terms of geostrophism, the occurrence of positive and negative return strokes mainly occurs from April to September, and the diurnal peak of positive and negative return strokes occurs at 1:00 a.m. The high value centers of negative ground flashback density were mainly concentrated in the mountainous areas with higher altitude. The positive and negative ground flashback density increased with the increase of altitude. (2) The influence of ground flashback activity and related meteorological conditions on the concentration of NO_x and O_3 near the ground in Hong Kong: Three research stations representing different land use types were selected. Principal Component Analysis/Absolute Principal Component Scoring (PCA/APCS) combined with Multivariate Linear Regression (MLR) model was used to analyze the concentration of NO_x and O_3, lightning location data and related meteorological data. It was found that the concentration of NO_x at the three stations increased on the day of lightning. The results show that land use types, lightning activities (e.g. ground flashback frequency and mean peak current) and related meteorological conditions (e.g. wind direction, wind speed, precipitation, temperature, relative humidity, cloud cover and cloud cover) are related to land use types. (3) Based on the verification of the atmospheric chemical effects of lightning induced by artificial lightning, the concentration changes of NO, O_3 and submicron fine particles were observed before and after five successful artificial lightning triggers on August 19, 2014, and it was found that NO was about half an hour before the lightning was triggered. The average concentration was 0.4 ppbv, and the peak concentration was 220.5 ppbv after the first successful lightning, and the NO concentration was also increased in varying degrees after the other four lightning. The concentration of O_3 increased before the artificial lightning, but decreased rapidly to the valley value of 16.9 ppbv. O_3 produced by corona discharge of edge natural lightning is related to the relatively high concentration of O_3 carried by subsidence airflow. The decrease of O_3 concentration after lightning may be caused by the titration of O_3 by NO produced by lightning. In addition, the concentration of sub-micron fine particles increases rapidly after successful lightning induction, which may be due to the rapid increase of O_3 concentration. Lightning process is conducive to the formation of new particles induced by ions. (4) Preliminary study on the chemical composition of particulate matter before and after artificial lightning by single particle aerosol spectrometer (SPAMS): before, during and after artificial lightning, the positive and negative ion average spectra show that the positive and negative ion average mass spectra of particulate matter and the lightning induction process. The statistical results of iron-containing particles show that the number of iron-containing particles in the first few minutes after successful lightning is significantly higher than other times, and the peak number of iron-containing particles appears slightly later than the peak concentration of NO. The number and proportion of iron particles in the lightning channel increase significantly, reflecting that the change of chemical composition in the lightning channel will have a certain impact on the chemical composition of particulate matter. The analysis of nitrogen particles shows that the lightning process may lead to nitrate in the atmospheric particulate matter. The increase.
【学位授予单位】：中国科学院广州地球化学研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X51;P427.3
[Abstract]:Lightning is a common natural phenomenon. Lightning occurs about 30-100 times per second on the earth. Lightning, as one of the most common meteorological disasters, directly threatens the safety of human life and property. Lightning is not only one of the major natural sources of nitrogen oxides (NO_x) in the atmosphere, but also directly and indirectly affects the concentration of atmospheric ozone (O_3). In addition, lightning may also induce the formation of new particles in the atmosphere. However, a comprehensive study of flash The effects of electrical activities and related meteorological conditions on the concentrations of NO_x and O_3 in the near-surface atmosphere and the changes of particulate matter concentrations and their chemical components during lightning have not been reported in China. Based on the topographic data, the temporal and spatial distribution characteristics of the ground lightning activity in Hong Kong and the influence of lightning on NO_x and O_3 in the near-surface atmosphere are discussed. The concentration and chemical composition of NO, O_3 and submicron fine particles before and after lightning occurrence are observed, and the possible atmospheric chemistry is discussed. On the one hand, this study has a certain guiding significance for lightning protection and disaster mitigation as well as the assessment of atmospheric environmental quality in thunderstorm season, on the other hand, it also provides a new method and a certain data basis for the in-depth study of lightning atmospheric chemical effect and its impact mechanism. Several aspects: (1) Spatial and temporal distribution characteristics of ground lightning activity in Hong Kong and its influencing factors: Through statistical analysis and correlation analysis of lightning location data, meteorological parameters and altitude data in Hong Kong from 2006 to 2012, it is found that the most frequent occurrences of ground lightning in Hong Kong from 2006 to 2012 are in 2010, at least in 2011; and on the basis of monthly variation. In terms of geostrophism, the occurrence of positive and negative return strokes mainly occurs from April to September, and the diurnal peak of positive and negative return strokes occurs at 1:00 a.m. The high value centers of negative ground flashback density were mainly concentrated in the mountainous areas with higher altitude. The positive and negative ground flashback density increased with the increase of altitude. (2) The influence of ground flashback activity and related meteorological conditions on the concentration of NO_x and O_3 near the ground in Hong Kong: Three research stations representing different land use types were selected. Principal Component Analysis/Absolute Principal Component Scoring (PCA/APCS) combined with Multivariate Linear Regression (MLR) model was used to analyze the concentration of NO_x and O_3, lightning location data and related meteorological data. It was found that the concentration of NO_x at the three stations increased on the day of lightning. The results show that land use types, lightning activities (e.g. ground flashback frequency and mean peak current) and related meteorological conditions (e.g. wind direction, wind speed, precipitation, temperature, relative humidity, cloud cover and cloud cover) are related to land use types. (3) Based on the verification of the atmospheric chemical effects of lightning induced by artificial lightning, the concentration changes of NO, O_3 and submicron fine particles were observed before and after five successful artificial lightning triggers on August 19, 2014, and it was found that NO was about half an hour before the lightning was triggered. The average concentration was 0.4 ppbv, and the peak concentration was 220.5 ppbv after the first successful lightning, and the NO concentration was also increased in varying degrees after the other four lightning. The concentration of O_3 increased before the artificial lightning, but decreased rapidly to the valley value of 16.9 ppbv. O_3 produced by corona discharge of edge natural lightning is related to the relatively high concentration of O_3 carried by subsidence airflow. The decrease of O_3 concentration after lightning may be caused by the titration of O_3 by NO produced by lightning. In addition, the concentration of sub-micron fine particles increases rapidly after successful lightning induction, which may be due to the rapid increase of O_3 concentration. Lightning process is conducive to the formation of new particles induced by ions. (4) Preliminary study on the chemical composition of particulate matter before and after artificial lightning by single particle aerosol spectrometer (SPAMS): before, during and after artificial lightning, the positive and negative ion average spectra show that the positive and negative ion average mass spectra of particulate matter and the lightning induction process. The statistical results of iron-containing particles show that the number of iron-containing particles in the first few minutes after successful lightning is significantly higher than other times, and the peak number of iron-containing particles appears slightly later than the peak concentration of NO. The number and proportion of iron particles in the lightning channel increase significantly, reflecting that the change of chemical composition in the lightning channel will have a certain impact on the chemical composition of particulate matter. The analysis of nitrogen particles shows that the lightning process may lead to nitrate in the atmospheric particulate matter. The increase.
【学位授予单位】：中国科学院广州地球化学研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X51;P427.3
【相似文献】
相关期刊论文 前10条
1 郄秀书,周筠s，
本文编号：2184058
本文链接：https://www.wllwen.com/shoufeilunwen/jckxbs/2184058.html
