中国地区闪电和对流层上部NOx的时空分布特征及其相关性分析

为了解闪电对对流层上部NO_x的贡献,本文利用美国全球水资源和气候中心（GHRC）提供的1995年4月~2005年12月的闪电卫星格点资料及高层大气研究卫星 (UARS) 上的卤素掩星试验装置 (HALOE) 1991年10 月~2005 年11月的观测资料,分析了中国地区闪电与对流层上部NO_x体积混合比的时空分布特征及两者的相关性.结果表明:中国地区闪电和对流层上部的NO_x在季节分布、年际分布和空间分布上保持很好的一致性,闪电是对流层上部NO_x的重要来源；NO极值高度在350 hPa左右,云闪直接产生的NO是极值产生的主要原因,NO₂的极值高度在250 hPa左右,因为闪电产生的NO在传输过程中会被氧化成NO₂并通过雷暴的垂直输送作用抬升到更高高度；强对流活动有利于NO_x的传输,而人类活动产生的NO_x一般较难输送到对流层上部,因此闪电多发区的NO_x极值较大,所在的高度也较高.

Comparison of Lightning Activity and NOx Distribution in the Upper Troposphere in China

In order to understand the contribution of lightning to the abundance of NO_x in the upper troposphere, the characteristics of spatial and temporal distribution of NO_x in the upper troposphere and lightning in China, and the relationships between them are analyzed in this paper. The lightning data (from April 1995 to December 2005) and the NO_x data (from October 1991 to November 2005) are obtained from the Global Hydrology Resource Center (GHRC), USA and the Halogen Occultation Experiment (HALOE) boarded on the Upper Atmosphere Research Satellite (UARS), respectively. It is found that lightning activities are in very good agreement with NO_x volume mixing ratio in seasonal variations, annual variations, and spatial variations. The results prove that lightning is an important source of NO_x in the upper troposphere. The height of the extreme value of NO is at about 350 hPa, while that of NO₂ is at about 250 hPa. Intra-cloud lightning-generated NO is the main reason for the extreme value, the NO will oxidize into NO₂ during the transmission process, and NO₂ will be transported to higher height through the thunderstorms. Strong convective is helpful to transport NO_x to the upper troposphere, while NO_x generated by human activities can hardly do this. Therefore, in the area that more lightnings occur, the extreme value is bigger and its height is higher.