日本地球惑星科学連合2018年大会

講演情報

[EJ] 口頭発表

セッション記号 A (大気水圏科学) » A-AS 大気科学・気象学・大気環境

[A-AS06] 大気化学

2018年5月24日(木) 13:45 〜 15:15 A05 (東京ベイ幕張ホール)

コンビーナ:岩本 洋子(広島大学 生物圏科学研究科)、中山 智喜(長崎大学 大学院水産・環境科学総合研究科)、豊田 栄(東京工業大学物質理工学院、共同)、江口 菜穂(Kyushu University)、座長:峰島 知芳(国際基督教大学)、滝川 雅之(国立研究開発法人 海洋研究開発機構)

13:45 〜 14:15

[AAS06-17] Methane exchange between atmosphere and ocean

★Invited Papers

*登尾 浩助1青木 伸輔1小宮 秀治郎4近藤 文義3伊東 雄樹1土井 俊弘1植松 光夫2松本 良1 (1.明治大学、2.東京大学、3.海上保安大学校、4.マックスプランク生物地球化学研究所)

キーワード:ガスフラックス、緩和渦集積法、太平洋

Methane (CH4) is one of the major greenhouse gases with approximate 30 times as much greenhouse effect as carbon dioxide. Sources of CH4 would be biogenic, thermogenic, and combustion. Agricultural lands are a major contributor to CH4 emission. Although the ocean is thought to be a sink for methane, little research has been conducted to directly measure CH4 flux on the ocean. Our objective was to gain our knowledge on the CH4 exchange between the atmosphere and the ocean by direct measurement of CH4 flux on a ship. Row, pitch, and yaw were detected in real time with three-axils inclinometer and accelerometer on board, and wind speed and wind direction were corrected to compensate ship's motion to separate upward and downward eddies of air. The methane concentration of upward and downward air was measured every 30 min to estimate CH4 flux with the relaxed eddy accumulation method. Methane concentration in the atmosphere varied along the course of the ship: (1) high in Tokyo and decreased to the equator; and (2) abruptly increased in the Berling Sea after the northern Pacific Ocean. Methane flux was tended to increase where CH4 concentration was high. As reported by the previous workers, we found the direct measurement of flux was larger than the conventional bulk method.