JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 A (大気水圏科学) » A-OS 海洋科学・海洋環境

[A-OS16] [EE] 地球規模環境変化に関する分野横断の海洋研究

2017年5月22日(月) 13:45 〜 15:15 ポスター会場 (国際展示場 7ホール)

コンビーナ:河宮 未知生(海洋研究開発機構)、伊藤 進一(東京大学大気海洋研究所)、栗原 晴子(琉球大学)、見延 庄士郎(北海道大学大学院理学研究院)

[AOS16-P02] Multi-year estimate of the air-sea CO2 flux in the Arctic with the use of the chlorophyll-a concentration

*安中 さやか1Siswanto Eko1Olsen Are2,7Hoppema Mario3渡邉 英嗣1Fransson Agneta5Chierici Melissa4村田 昌彦1小杉 如央6Lauvset Siv7Mathis Jeremy8 (1.海洋研究開発機構、2.University of Bergen、3.Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research、4.Institute of Marine Research、5.Norwegian Polar Institute、6.気象研究所、7.Bjerknes Centre for Climate Research、8.NOAA Arctic Research Program)

キーワード:CO2 flux, Arctic, chlorophyll-a, SOCAT

We examined the relationship between partial pressure of CO2 in the surface water (pCO2w) and chlorophyll-a concentration (Chl-a) in the Arctic. The relationship between pCO2w and Chl-a is negative where Chl-a < 1 mg m-3, but there is no significant relationship where Chl-a > 1 mg m-3. In the Greenland/Norwegian Seas, a relationship between pCO2w and Chl-a is strongly negative in spring and weakly negative in summer. Chl-a is higher in summer than in spring, while nutrient concentration is high in spring and low in summer there. A positive relationship between pCO2w and Chl-a is found in the Barents Sea in summer when Chl-a values decline while pCO2w remains at a relatively constant low level. In the Kara and East Siberian Seas and the Bering Strait, the relationships are positive because of high pCO2w and Chl-a water in the coastal region.
We estimated monthly air–sea CO2 flux in the Arctic north of 60°N from 1997 to 2014 by applying a self-organizing map technique with Chl-a, SST, SSS, SIC, xCO2a, and geographical positions. The addition of Chl-a as a training parameter enables us to improve the estimate of pCO2w through reproducing its decline in spring by biological production. A significant CO2 uptake of 180 ± 130 TgC yr–1 in the Arctic Ocean was obtained. This estimate has been much improved compared to a previous estimate thanks to the use of Chl-a, but to some extent also due to a higher number of CO2 data.