| Co-Investigator(Kenkyū-buntansha) |
MATSUMI Yutaka Solar-Terrestrial Environment Laboratory Nagoya University Professor, 太陽地球環境研究所, 教授 (30209605)
KITA Kazuyuki Research Center for Advanced Science and Technology, The University of Tokyo Research Associate, 先端科学技術研究センター, 助手 (30221914)
KOIKE Makoto Department of Earth and Planetary Science Graduate School of Science Associate Professor, 理学系研究科, 助教授 (00225343)
SUZUKI Katsuhisa Faculty of Education Yokohama National University Professor, 教育人間科学, 教授 (60011764)
KITADA Toshihiro Toyohashi Technology and Science University Professor, 工学部, 教授 (40093231)
TAKEGAWA Nobuyuki Solar-Terrestrial Environment Laboratory Nagoya University Research Associate, 太陽地球環境研究所, 助手 (00324369)
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| Research Abstract |
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.
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