著者

Tomohiro Toki Kiichiro Kawamura Urumu Tsunogai Toshitaka Gamo

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.25, pp.1-12, 2017-09-01 (Released:2017-09-28)

参考文献数

39

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We describe in detail the pore water chemistry in the sediments below a white mat around a bunch of bananas at a water depth of 2,200 m in the Tenryu Submarine Canyon. We infer the metabolism of microbes in the sediments around the bananas based on the chemical and isotopic compositions of the pore water. On the basis of the relation between ammonia and total carbonate (ΣCO2) concentrations in the pore water, we identified that an excess ΣCO2 was distributed around the bananas that cannot be explained by the decomposition of organic matter derived from marine organisms, indicating that the bananas decomposed to generate the excess ΣCO2. We conclude that the bananas built a local organic-rich environment, stimulating the activity of organotrophic bacteria.

著者

Chihiro Kodama Akira Kuwano-Yoshida Shingo Watanabe Takeshi Doi Hiroki Kashimura Tomoe Nasuno

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.28, pp.5-34, 2019-04-01 (Released:2019-04-03)

参考文献数

133

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The JAMSTEC Model Intercomparison Project (JMIP) provides a first opportunity to systematically compare multiple global models developed and/or used in JAMSTEC with the aim of moving toward better weather and climate predictions. Here, we evaluate climate simulations obtained from atmospheric models (AFES and MIROC5), atmospheric model with slab ocean (NICAM.12), and fully coupled model (SINTEX-F1 and SINTEX-F2). In these simulations, the sea surface temperature is fixed (for AFES and MIROC5) or nudged (NICAM.12, SINTEX-F1, and SINTEX-F2) to the observed historical one. We focus on the climatology and variability of precipitation and its associated phenomena, including the basic state, the energy budget of the atmosphere, extratropical cyclones, teleconnection, and the Asian monsoon. We further discuss the possible causes of similarities and differences among the five JMIP models. Though some or most of the dynamical and physical packages in the JMIP models have been developed independently, common model biases are found among them. The AFES and MIROC5, and the SINTEX-F1 and SINTEX-F2, show strong similarities. In many respects, NICAM.12 shows unique characteristics, such as the distributions of precipitation, shortwave radiation, and explosive extratropical cyclones and the onset of the Asian summer monsoon. To some extent, the similarities and differences among the JMIP models overlap with those among the Coupled Model Intercomparison Project Phase-5 (CMIP5) models, suggesting that JMIP can be used as a simple and in-depth version of CMIP to investigate the mechanisms of model bias. We suggest that this JMIP framework could be expanded to an intercomparison of weekly-to-seasonal scale weather forecasting; here, more fruitful discussion is expected through intensive collaboration among modeling and observation groups.

著者

三浦 誠一

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.2009, pp.81-87, 2009

被引用文献数

4

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海洋研究開発機構 (JAMSTEC) では, 海底下深部構造を求め地震や津波の発生メカニズムを解明するため, 1995年より制御震源による構造探査を開始した. 1997年からは海溝型巨大地震発生過程解明をめざして「かいれい」に構造探査システムを艤装, 1999年にエアガン大容量化とOBS100台化および「かいれい」「かいよう」2船体制となった. 2004年に伊豆小笠原海域等での集中的探査に対応するため, ストリーマーケーブル延長やOBS台数追加という増強を実施した. これらにより海溝型巨大地震発生過程や島弧成長過程の解明に関する重要な知見が得られた. しかし今後構造研究と掘削等による物質科学との統合をめざすため, 構造探査システムの高精度化をはかる必要がある. このような観点から, 2008年に「かいれい」のエアガンアレイチューンドアレイ化, ストリーマーケーブルの高分解能化を行い, 想定した性能を確認した. 今後も科学的要求にこたえるべく技術的更新や増強をはかる必要があると考えられる.

著者

松本 和彦 藤木 徹一 本多 牧生 脇田 昌英 川上 創 喜多村 稔 才野 敏郎

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.14, pp.17-25, 2012

被引用文献数

1

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海洋地球研究船「みらい」では,採水にニスキン−X採水器を取り付けたCTD採水システムを使用している. ニスキン−X採水器は蓋閉用のスプリングが採水器外側に配置され, ボトル内部へのゴムや微量金属による汚染を極力排除できる仕組みとなっている. 通常, 一次生産量測定用のサンプリングには海水サンプルへの微量金属等の汚染防止を徹底するため, 内部にテフロンコーティングを施し, ボトル内部及び部品各種を酸洗浄した採水器をクリーンニスキンとして使用している. クリーンニスキンとその他のノーマルニスキンで採水した場合に, 実際に一次生産量に差が生じるのかを確かめたところ, ノーマルニスキンで採水した場合に一次生産量測定値が激しく低下した. その差を生じる原因を把握するための追加実験を行うと, ノーマルニスキンで使用しているニトリルゴム製Oリングが一次生産を阻害していることが明らかとなった.

著者

Takeshi Enomoto

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.6, pp.21-30, 2007-11-01 (Released:2020-02-19)

参考文献数

22

被引用文献数

8 10

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The albedo of the ocean surface is of primary importance in the radiative energy balance of the Earth. It takes the smallest value of close to 0 over ocean water and the largest value of nearly 1 over snow-covered sea ice. The albedo of ocean water is determined by of the solar zenith angle, slope of the surface and optical properties of the atmosphere and ocean. The albedo of sea ice is significantly influenced by snow cover. During the warm season, ponds of melt water of snow and ice result in large reduction of albedo. Based on the knowledge from foregoing observational and modelling studies, the treatment of the ocean surface albedo in AFES (atmospheric general circulation model for the Earth Simulator) has been improved. Recent modifications to albedo parametrizations incorporated in AFES are described and optimum values for various parameters are adjusted to the observation data. The effects of albedo on global energy balance and atmospheric circulation are discussed.

著者

Hayato Ueda

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.14, pp.1-15, 2012 (Released:2012-04-18)

参考文献数

8

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The top clinometer is a newly developed payload tool which enables a submersible vehicle to directly measure orientation of planar geological structures (e.g. bedding planes, faults) on seafloor outcrops. It consists of a disc and central vertical bar, both graduated at 1 cm scales, and a handle. On seafloor outcrops, the disc is placed on the geological surface of interest by a manipulator, and is captured by a still camera. The orientations are determined via simple onboard graphic analyses of the images obtained and the submersible log data. Strike and dip of the surface structures are routinely calculated by a macro program within a Microsoft Excel worksheet. Theoretical and laboratory tests suggest errors of the measurements in the same order as magnetic clinometer compasses commonly used for on-land geological surveys. Camera installation angles to the submersible Shinkai 6500 were also calibrated based on on-deck tests during R/V Yokosuka YK08-05 and YK10-13 Leg2 cruises. Results of three practical measurements suggested that speed of the operation depends heavily on the time spent looking for the target surfaces and the time for communication between operators and scientists. Besides these factors, a measurement can be taken in as little as five minutes. This simple and quick method improves the quality of structural measurements for submarine geology.

著者

小池 義和 森野 博章 栗原 邦彰 糸井 成夫 河上 達 清水 悦郎

出版者

Japan Agency for Marine-Earth Science and Technology

雑誌

JAMSTEC Report of Research and Development (ISSN:18801153)

巻号頁・発行日

vol.19, pp.49-58, 2014

被引用文献数

3

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近年,深海探査の要求は高まっており,低コストで簡易な深海探査システムの実現が望まれている.江戸っ子1号プロジェクトは,東京下町の中小企業,大学,研究機関,金融機関,企業有志がフリーフォール型の簡易深海探査システム実現を目的として集まって実施したプロジェクトである.プロジェクトでは,深海7800 mでの3Dビデオ撮影に成功している.このプロジェクトに参加した筆者らは,江戸っ子1号プロジェクトで使用したフリーフォール型深海探査システムのガラス球内部に温度センサと気圧センサを設置し,深海の温度プロファイル,着底,離底の検知ができないかを検討した.その結果,センサ出力から得られる体積変化分から着底,離底の検出が可能となることを確認した.