Japan Geoscience Union Meeting 2015

Presentation information


Symbol A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS21] Atmospheric Chemistry

Wed. May 27, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Yousuke Sawa(Oceanography and Geochemistry Research Department, Meteorological Research Institute), Nobuyuki Takegawa(Graduate School of Science and Engineering, Tokyo Metropolitan University), Yugo Kanaya(Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology), Kenshi Takahashi(Research Institute for Sustainable Humanosphere, Kyoto University), Hiroshi Tanimoto(National Institute for Environmental Studies)

6:15 PM - 7:30 PM

[AAS21-P12] Atmospheric hydorogen mesurements in the western North Pacific

*Kazuhiro TSUBOI1, Hidekazu MATSUEDA1, Yousuke SAWA1, Yosuke NIWA1, Shinya TAKATSUJI2, Hiroaki FUJIWARA2, Kohshiro DEHARA2, Tomoki OKUDA2, Yoki MORI2 (1.Meteorological Research Institute, 2.Japan Meteorological Agency)


Molecular hydrogen (H2) plays a significant role in global atmospheric chemistry due to its role in CH4 -CO-OH cycling and water vapor source in the stratosphere. The balance of H2 could change with the implementation of a new H2 energy carrier. Therefore, it is important to establish its global budget and atmospheric trend (WMO/GAW Report No.197, 2011).
We started atmospheric H2 measurement at Minamitorishima (MNM) from Nov. 2011. The measurement system using a GC-RGD (gas chromatographs equipped with a reduction gas detector) was installed for sirmulteneouse analyses of H2 and carbon monoxide at 3 stations of MNM, Yonagunijima (YON), and Ryori (RYO) operated by Japan Meteorological Agency (JMA). In this study, high-precision H2 standard gases are prepared to determine the atmospheric concentrations from the output signal of the GC/RGD.
The H2 concentrations at MNM varied seasonally from 490 ppb to 560 ppb with a yearly mean of about 520 ppb. The H2 variations often show distinct episodic events with enhanced concentrations on a synoptic scale in winter. This result indicates that H2 increases are caused by the long-range transport of Asian polluted air masses to the station, suggesting that H2 is a good tracer for identifying continental air masses in winter season. On the other hand, the H2 concentrations are higher and stable in summer season. This result indicates that the maritime air masses are dominated, and the influence of soil absorption was small.