Tropospheric photochemistry and ozone budget

在1998年8 - 10月和1999年进行的生物质燃烧和闪电实验（BIBLE） a和B期间，在西太平洋和澳大利亚上空进行了O_3， CO，总活性氮（NO_y）， NO和非甲烷碳氢化合物（NMHCs）的原位飞机测量。由于活跃的对流，这些物种的混合比在热带太平洋整个对流层达到最小值，尽管新几内亚附近闪电产生的NO偶尔会引起活性氮的增强。将热带对流层上层O_3、CO、NO_y和NO的低值与三维化学和输送模式进行了比较，较好地反映了O_3、NO_y和NO从中纬度北部到赤道的纬向变化。在澳大利亚上空，整个对流层中O_3、CO、NO_y、NO和NMHCs的水平高于1998年和1999年在热带太平洋观测到的水平。由于下沉，澳大利亚上空的生物质燃烧仅在边界层内强烈地提高了这些物种的混合比率。根据14天的反轨迹，确定了来自印度尼西亚、印度洋、非洲和中纬度南部的自由对流层气团。这些气团中O_3、CO、NO_y和NMHCs的含量远高于热带太平洋，这主要是由于生物质燃烧和闪电对这些气团的影响更大。除中纬度南部气团的中位数较高外，各气团的中位数基本一致。发现生物质燃烧和闪电对这些气团中的O_3及其前体很重要。

In situ aircraft measurements of O_3, CO, total reactive nitrogen (NO_y), NO, and non-methane hydrocarbons (NMHCs) were made over the western Pacific Ocean and Australia during the Biomass Burning and Lightning Experiment (BIBLE)-A and B conducted in August-October 1998 and 1999. The mixing ratios of these species reached minimum values over the tropical Pacific Ocean throughout the troposphere due to active convection, although occasional enhancements in reactive nitrogen occurred caused by NO production by lightning near New Guinea. The low values of O_3, CO, NO_y, and NO in the tropical upper troposphere are compared with a 3-dimensional chemistry and transport model, which reproduces the latitudinal variations of O_3, NO_y, and NO from northern midlatitudes to the equator reasonably well. Over Australia, the levels of O_3, CO, NO_y, NO, and NMHCs were elevated throughout the troposphere over those observed in the tropical Pacific both in 1998 and 1999. Biomass burning over Australia strongly enhanced the mixing ratios of these species only within the boundary layer due to subsidence. Free tropospheric air masses originated from Indonesia, the Indian Ocean, Africa, and southern midlatitudes were identified basing on 14-day back trajectories. The levels of O_3, CO, NO_y, and NMHCs in these air masses were much higher than those from the tropical Pacific due to their stronger sources from biomass burning and lightning. The median values of these species in different types of air masses were similar except for the southern midlatitude air, which showed somewhat higher values. Biomass burning and lightning are found to be important for O_3 and its precursors in these air masses.