估算闪电产生氮氧化物量的研究回顾与进展

在对流层内,闪电产生的氮氧化物(LNOx)是氮氧化物(NOx)的主要来源之一,这一区域内,由于NOx生命史较长,且控制着对流层臭氧(O3)和氢氧根(OH)的含量,影响着全球大气环境和气候变化.针对LNOx量的估算这一大气化学及雷电物理领域内的研究热点,介绍了NOx的主要来源、LNOx的产生机制及其对气候变化的重要性,详细综述了国内外现有的估算LNOx量的主要方法和估算结果.综述结果表明,目前估算LNOx量采用的研究方法主要有野外观测、实验室模拟、理论模式计算和卫星数据反演,主要通过观测或假设得到单位能量产生的NOx量,或单位通道长度产生的NOx量,同时通过观测或假设得到一次放电通道产生的总能量或一次放电的总通道长度,进而外推或数值模拟某一局地区域或全球的LNOx.由于不同地区、不同雷暴、甚至不同的闪电个体之间的显著差异导致不同的研究者估算LNOx时采用的参数值不同,进而使得LNOX估算量的结果差异较大,不确定性增大.近30年LNOx较为精确的产量计算结果平均值为5.2(2.8 ～9.1) Tg/a.最后提出,今后需继续对比分析利用先进的观测手段得到NOx和闪电的野外观测和卫星观测数据,进一步认识LNOx的产生机制,得到针对不同地区、不同强度的雷暴和不同的闪电个体估算NOx的参数取值,进一步减小估算LNOx时所用到的各个参数的不确定性.在此基础上,利用大气化学数值模式模拟局地或全球LNOx的产生和演变及其对其他空气成分的影响和作用,进一步认识LNOx在全球气候变化中的作用.

Review and Progress of Estimate on Nitrogen Oxide Production by Lightning

WT5BZ]Nitrogen oxide (NO_X) is one of the most important lighting produced molecules, primarily because it facilitates chemical reactions in the troposphere that determine the concentrations of ozone (O₃) and of the hydroxyl radical (OH). NO_X source, LNO_X mechanism and their significance on climate change are introduced for understanding the estimate of LNO_X, which is a research hotspot in atmospheric chemistry and lighting physics. Then, the main methods and results of estimate on LNO_X are summarized. The conclusions show that, in situ measurement, laboratory simulation, theoretical extrapolation and retrieval of satellite data are the major research methods in this field. Through these methods, NO_X production per unit lightning energy or unit lightning channel length are obtained, then combined with the total energy or channel length of lightning, the LNO_X production in local or global is estimated by extrapolation or numerical modeling. Due to the different region, thunderstorm and even lightning are presented remarkable difference, and the parameters chosen by different researchers are various, leading to the diversity of results. In the past three decades, the mean value of relatively accurate production calculations has been 5.2(2.8~9.1) Tg/a. Therefore, advanced NO_X observations of in-situ and space measurements should be analyzed to realize the LNO_X mechanism. Appropriate NO_X parameters should be chosen in varied intensity thunderstorm and individual lightning to reduce the parameter uncertainties. On that basis, atmospheric chemical model is integrated to simulate LNO_X generation, development and the influence of other air composition regionally and globally. Thus, the role of LNO_X in global climate change would be better recognized.