南大洋インド洋区季節海氷域における溶存炭酸物質の季節変化

第6回極域科学シンポジウム分野横断セッション：[IB1] 海氷域における生物地球化学的研究11月17日（火）　統計数理研究所 セミナー室1（D305

Controlling processes of pCO2 under coastal fast ice around Syowa Station during austral summer; implication for high productive "stealth polynya"

第2回極域科学シンポジウム　共通セッション「海氷圏の生物地球化学」 11月16日（水） 統計数理研究所 3階セミナー

第54-55次日本南極地域観測隊（JARE-54&-55）におけるアイスフェンスを用いた氷海内海洋観測

第52次日本南極地域観測隊より開始した氷海内における海洋生態系モニタリング観測において，観測機器の破損やプランクトン試料へのダメージを抑えるために，測器を海氷からガードする“アイスフェンス”を用いている．これまで一定の成果を挙げてきてはいるが，近年の昭和基地周辺における厳しい氷状においても観測を可能とするために，アイスフェンスの改良を継続した．本報告では第54次隊および第55次隊において実施したアイスフェンスの改良の紹介と，実際の現場における観測の概要について報告する．The marine biological monitoring program in the sea-ice area off Syowa Station was started by the 52nd Japanese Antarctic Research Expedition. The use of an “ice-fence” protected observation equipment (e.g., plankton nets and CTDs) from damage due to sea-ice. However, heavy sea-ice conditions have occurred frequently off Syowa Station in recent years. Therefore, we modified the ice-fence (diameter: 1000mm, height:1200mm, stainless steel) to enable observations under heavy sea-ice conditions. This report describes the results of field tests of the modified ice-fence performed during the 54th and 55th Japanese Antarctic Research Expeditions

Seasonal and Inter-Annual Variations in pCO2sea and Air-Sea CO2 Fluxes in Mid-Latitudes of the Western and Eastern North Pacific during 1999-2006 : Recent Results Utilizing Voluntary Observation Ships

We have investigated the seasonal and inter-annual variations of the difference in partial pressure of CO2 between surface seawater (pCO2sea) and overlying air (pCO2air) and the air-sea CO2 flux in the mid-latitudes of the western North Pacific (WNP; 25-40°N, 140-170°E) and eastern North Pacific (ENP; 25-40°N, 120-150°W) from 1999 to 2006 using the latest voluntary observation ship data. In the WNP and ENP, the area-averaged ΔpCO2 (pCO2air - pCO2sea) was at its minimum in late summer (-4.6 to 6.7 μatm in the WNP and -32.5 to -20.5 μatm in the ENP) and at its maximum in late winter (51.0 to 59.8 μatm in the WNP and 35.1 to 46.2 μatm in the ENP). The WNP acts as a moderate sink for atmospheric CO2 (4.1 to 5.5 mmol m^[-2] d^[-1]), while the ENP acts as a weak sink (1.1 to 1.9 mmol m^[-2] d^[-1]). Because ΔpCO2 is mainly controlled by pCO2sea, we have evaluated the effect of the factors controlling pCO2sea : sea surface temperature (SST), salinity (SSS), dissolved inorganic carbon (TCO2), and total alkalinity (AT). In the WNP, not only SST but also TCO2 plays an important role in the seasonal pCO2sea variation, while the SST could only explain most of the pCO2sea variation in the ENP. From 1999 to 2006, pCO2sea increased at a significantly lower rate (0.53±0.11 μatm yr^[-1]) than pCO2air (1.81±0.01 μatm yr^[-1]) in the WNP, and at a slightly lower rate in the ENP (1.32±0.16 μatm yr^[-1]). The air-sea CO2 flux increased at a rate of 0.19±0.05 mmol m^[-2] d^[-1] yr^[-1] in the WNP and 0.09±0.03 mmol m^[-2] d^[-1] yr^[-1] in the ENP, suggesting that the WNP is a stronger sink for atmospheric CO2

Report on a modified ice-fence for oceanographic observations under heavy sea-ice conditions during JARE-54 and JARE-55

The marine biological monitoring program in the sea-ice area off Syowa Station was started by the 52nd Japanese Antarctic Research Expedition. The use of an “ice-fence” protected observation equipment (e.g., plankton nets and CTDs) from damage due to sea-ice. However, heavy sea-ice conditions have occurred frequently off Syowa Station in recent years. Therefore, we modified the ice-fence (diameter: 1000mm, height:1200mm, stainless steel) to enable observations under heavy sea-ice conditions. This report describes the results of field tests of the modified ice-fence performed during the 54th and 55th Japanese Antarctic Research Expeditions