著者

渡辺 正之 門馬 大和

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.8, no.1, pp.3-13, 2003 (Released:2019-02-16)

---

Search and recovery operations for the failed H-II Rocket Flight No.8 engine were carried out in 1999 at the request of the National Space Development Agency of Japan (NASDA). The rocket was launched in November 15, 1999 and the first stage engine stopped in 4 minutes. The engine fell in the northwestern Pacific Ocean region at a water depth ofabout 3,000m. The predicted search area was limited to 3.3km width and 26km length ofbox by orbital calculation ofthe NASDA. The size ofthe main engine was about 3.4m in height, with a diameter about 1.8m. The Japan Marine Science & Technology Center (JAMSTEC) employed the latest equipment for the three search cruises and the following procedures: (1) wide area survey for the submarine topography using multi-narrow-beam echo sounder (Seabeam 2112) which was equipped on R/V ”Kairei”, (2) narrow area survey for the unique sonar contacts by side scan sonar on a 10,000m class ROV ”Kaiko” and the deep tow sonar towed at a speed of0.5 knots and a swath width of 1,000m for each side, and (3) detailed visual observation of the engine by the super-HARP camera (an ultra-sensitive color TV camera) or the 3CCD TV camera which was equipped on the deep tow camera and a 3,000m class ROV ”Dolphin-3K”. As a result, the JAMSTEC was able to locate the engine in approximately 5 weeks. Then, NASDA employed an U.S. salvage company for recovery operation that was carried out by a 6,000m class ROV ”Remora6000”and succeeded in recovering the engine from the deep seafloor within only two months after the launch. The success of the mission demonstrated the high of level technical expertise and underwater technology that JAMSTEC has cultivated over the last 30 years.

著者

亭島 博彦 江里口 知巳 柳田 圭悟 堀口 文男

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.19, no.2, pp.1-11, 2014 (Released:2014-06-26)

参考文献数

35

---

We investigated radioactivity concentrations of 134Cs and 137Cs in river waters, Tokyo Bay sediments and Japanese whitings (Sillago japonica) lived in Tokyo Bay. Water samples were taken from Arakawa river mouth and Edogawa river mouth. Due to precipitations at inland areas, the river mouth waters had high concentrations of suspended solid (SS) and radiocesium on July 3 2012. The water sample taken from Arakawa river mouth showed higher concentration of radiocesium than that of from Edogawa river mouth. The sediment sample taken from Arakawa river mouth showed the highest concentration of radiocesium in sediments which were sampled on July 3 2012. In the vicinities of river mouth at the sea, sediments showed decreasing of radiocesium concentration (Bg/1,000 cm3 of sediment) with distance from river mouths, but there was no the same distribution pattern with the radiocesium concentrations (Bg/kg of dried sediment) of them. Values of 134Cs/137Cs activity ratio in sediments suggested that the 137Cs, which was generated by nuclear weapon tests or others before the Fukushima Daiichi Nuclear Power Station accident, was included in the river mouth sediments, and these estimated values was 80 Bq/kg-dry in Arakawa river mouth, and 30 Bq/kg-dry in Edogawa river mouth. Effective ecological half-lives of radiocesium in the sediments taken from off the coast of Kisarazu-shi, Chiba, were about one year of 134Cs and about three years of 137Cs. We recognized that the radiocesium activity concentrations in Japanese whitings living in Tokyo Bay are in safe level as a food. Effective ecological half-life of 137Cs in Japanese whiting was estimated for 1.1 ± 0.4 year. Values of 134Cs/137Cs activity ratio of Japanese whitings in 2012 suggested that the radiocesium exposed experience of each fish differed from two year old fish and three year old fish.

著者

江里口 知己 堀口 文男 亭島 博彦 中田 喜三郎 高倍 昭洋 田口 浩一

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.19, no.2, pp.35-41, 2014 (Released:2014-06-26)

参考文献数

17

被引用文献数

1

---

We have developed a bioaccumulation model to estimate the concentration of hazardous chemicals accumulated in marine organisms. In this study, we applied this bioaccumulation model to estimate the concentration of radioactive materials in coastal fish. Target substances were radiocesium (134Cs, 137Cs) and the target fish were Japanese whiting (Sillago japonica) in Tokyo Bay. The radiocesium concentrations in sediments and fish were examined by field sampling on July 3 and August 9, 2012 in Tokyo Bay. The time course of radiocesium concentrations in Japanese whiting after the Fukushima Daiichi nuclear disaster was simulated using the model. Our model showed that good results were obtained by using the assimilation efficiency parameter of 10–20%, and radiocesium concentrations in Japanese whiting were about same as the levels recorded in the field sampling (517 days after the disaster). In the Edogawa River and the Arakawa River estuary, where high radiocesium concentrations were observed in sediments, Japanese whiting showed accumulations of 134Cs and 137Cs estimated at 5.0 Bq/kg-wet and 6.5 Bq/kg-wet, respectively.

著者

落合 健 國仲 彰 土居 七奈美

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.18, no.1, pp.1-12, 2012 (Released:2019-02-16)

---

The Japan Maritime Self Defense Force (JMSDF) quickly began disaster relief operations from the sea at the coast of Sanriku after the Great East Japan Earthquake. We observed in situ situation of our activity area because we had to estimate the impact of the advection and diffusion of the radioactive substance in the sea. Two survey ships ”Wakasa” and ”Nichinan” of JMSDF observed the temperature, salinity and current in detail at the wide area of offshore Sanriku and 30 NM distant from Fukushima No.1 Nuclear Power Plant (NPP), Tokyo Electric Power Company in April and May 2011. No strong current exist in the area near Fukushima No.1 NPP. Southward current with tidal component dominate during the observation. The upwelling current is also observed along the continental slope off the coast of Sanriku. These data will be provided as the initial value of the simulation study on the diffusion of the radioactive substance and the spatiotemporal reference value that simulation model should resolve.

著者

武尾 実 大湊 隆雄 前野 深 篠原 雅尚 馬場 聖至 渡邉 篤志 市原 美恵 西田 究 金子 隆之 安田 敦 杉岡 裕子 浜野 洋三 多田 訓子 中野 俊 吉本 充宏 高木 朗充 長岡 優

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.24, no.1, pp.45-56, 2018 (Released:2018-08-30)

参考文献数

12

---

Nishinoshima is an andesitic stratovolcano located in Ogasawara Islands, Japan. In November 2013, island-forming eruption started. Before the eruption, Nishinoshima was a small island of the area of 0.29 km2 and elevation of 25 m but it had a huge edifice rising 3,000 m from the sea floor. By March 2016, area and elevation reached 2.7 km2 and 140 m, respectively. We conducted various types of geophysical observations at this “difficult-to-access island” (950 km from Tokyo taking 90 min by Jet plane, or 24 h by ship). In June 2016, we conducted airborne observations using unmanned helicopter, collecting 250 grams of scoria and detailed 4K images of lava flows. OBSs (Ocean Bottom Seismometers) were deployed around Nishinoshima in four periods. From February 2015 to May 2017, characteristic waveforms dominated at 4–8 Hz band were frequently observed. Comparisons with infrasonic records and video images revealed that the 4–8 Hz seismic signals were associated with eruptions at pyroclastic cone. The number of seismic signals of this type declined from July 2015, and disappeared in November 2015, suggesting that the eruptive activity started declining in July 2015 and ceased in the middle of November 2015. In October 2016, we landed and deployed a broadband seismometer and an infrasonic sensor in the old Nishinoshima, collecting a lot of new lava, deposits, and ash samples. We demonstrated a capacity of remote-island volcano monitoring system for one day test navigation circling around Nishinoshima. After one and a half year quiescence, a new eruptive phase started in April, 2017. Our on-land seismic sensor detected precursory signals as early as April 17. The seismometer also recorded characteristic waveforms during the very early stage of the new eruption phase before data transmission was terminated on April 21.

著者

鈴木 宏枝 山内 束 宮城 伸 齋藤 秀亮 園田 朗

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.25, no.1, pp.21-28, 2019 (Released:2019-08-07)

参考文献数

9

---

JAMSTEC has participated in the Tohoku Ecosystem-Associated Marine Sciences project (TEAMS) which scientifically clarifies the impact and recovery process of the Great East Japan Earthquake on marine ecosystems in the Tohoku region and supports the rehabilitation of fisheries and industries. JAMSTEC develops and operates systems for managing and publishing data and information obtained from observations of TEAMS. One of them is the system for collecting and archiving obtained information of biological observation at the field observation. This system enables to archives and edits marine biological observation information in Web application by collecting marine biological observation information such as photos and related information and uploading it using mobile application.

著者

大野 檀 脇田 典英 広川 潔

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.14, no.2, pp.55-65, 2008 (Released:2019-02-16)

---

Scientific research in the deep ocean is a recent branch of wide-ranging marine research. The requirements of deep ocean scientific research have led to increasingly larger areas to be investigated while the mesh of investigations has become finer and finer, and deeper and deeper. In the deep seas the scientist ventures into an unlimited treasure house of knowledge: it is truly a voyage into the unknown. It has been almost twenty years since ”Shinkai6500” was launched in 1989. and the vehicle providing the world's greatest depth capability for a manned submersible, and also the vehicle has been providing for scientists a means to enable safely access and directly observe the deep ocean at a time when it was difficult for a man to venture to the deep seafloor. However, the time has come to consider a future deep submergence research vehicle as a succeeding vehicle for ”Shinkai6500”. This paper covers the result of study on the conceptual designs of two types of manned deep submergence research vehicles: 11000m submergence vehicle (full depth) and 6500m submergence vehicle (two spheres). On the other hand, during this same time period of twenty years, remotely operated vehicles and autonomous unmanned vehicles were developed worldwide and became available with advanced controlling and sensing technologies. Today, a lot of investigations and operations in the deep sea are utilizing these unmanned systems. Nevertheless, it is still very important that humans work in situ to directly observe and act. This man's capability generating innovative knowledge and hypotheses will be necessary at any time and in any period. Even if unmanned technologies are advanced in the field of natural science, the necessity of field work with man's presence will not be diminished. Consequently, future capable manned submergence vehicles that are responsive to the needs of scientific research in the deep ocean must be used in collaboration with various kinds of unmanned vehicles. This study was carried out by the ”ad hoc Committee” organized in the Japan Deep Sea Technology Association with additional current status regarding ”Shinkai6500”.

著者

佐藤 麟太郎 奥村 真子 黄 国宏 長谷川 浩 三木 理

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.27, no.1, pp.45-53, 2022-07-30 (Released:2022-08-27)

参考文献数

40

---

Recently, a great interest has been observed in using marine species for coastal environmental impact assessment. Embryos of brown macroalga, Sargassum horneri, distributed throughout the northwest Pacific coast, appear be a promising marine indicator for such assessments. This study identified the effects of copper (Cu–EDTA) on the germling growth of S. horneri. Following exposure to various copper concentrations for 21 days, the germination rate, specific growth rate, and final thallus area of S. horneri germlings were measured. The germination of the embryo was completely inhibited when exposed to 10 µg/L, and the no observed effect concentration (NOEC) for germination was estimated as 5 µg/L. Since the incubation period was longer for lower copper concentrations, growth inhibition could be clearly observed and was deduced to be a chronic toxicity effect. The median effective concentration (EC50) and NOEC for the final thallus area were 0.50 and 0.16 µg/L, respectively. The results demonstrated that the embryos of S. horneri are more sensitive to copper than other seaweeds, further suggesting that its growth patterns can effectively be utilized to assess coastal environmental impacts.

著者

鈴木 直弥 上田 陽平 高垣 直尚 植木 巌 池田 篤俊

出版者

Advanced Marine Science and Technology Society

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.27, no.1, pp.73-79, 2022-07-30 (Released:2022-08-27)

参考文献数

23

---

Drag coefficient on the ocean surface is determined by various studies based on different mechanisms, such as turbulence and wave breaking, closely related to wind speed. The global ocean datasets of wind speed are distributed by various temporal resolutions based on reanalysis, assimilation, and satellite data. Recently, the wind speed data with higher temporal resolution have been provided. Using 6-hourly and hourly wind datasets, the air-sea momentum fluxes were estimated by several drag coefficient models proposed by Large & Yeager (2009), Andreas et al. (2012), Takagaki et al. (2012), & Hwang (2018). The globally averaged annual mean air-sea momentum fluxes were derived from the different drag coefficient models. The maximum difference of the annual mean values among the models reaches approximately 30% of annual mean values. The meridional structure of zonally averaged annual mean air-sea momentum flux has double peak at relatively higher latitudes from 40°S/N to 60°N/S. At those peaks maximum difference among the models reaches more than 30% of the zonally averaged annual mean. In terms of differences in temporal resolution on the wind speed datasets on each grid, the differences between hourly and 6-hourly wind data became larger with decreasing average period. The maximum difference of 66.7% was recognized on daily mean. The large difference was remarkable in higher wind speed regions, such as typhoon’s paths in the western Pacific. The effects of wind variability on different temporal resolution datasets are significant for estimating the air-sea momentum flux.

著者

倉本 真一

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.24, no.2, pp.39-44, 2018 (Released:2018-12-28)

参考文献数

4

---

Importance of scientific ocean drilling was becoming more widely known in the Japanese scientific community, based upon the results of DSDP/IPOD/ODP by late 80s. Many scientific and engineering discussions took place domestically and internationally, and finally those discussions led the Japanese government to decisively move forward with the construction of D/V Chikyu. Finally, Chikyu was delivered to the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) in July 2005. Chikyu was designed and built as a scientific ocean drilling vessel capable of riser drilling in water depths of 2,500 m (future target is 4,000 m class). Chikyu can drill in deeper water and to deeper sub sea floor depths than any other scientific drilling platforms. Chikyu’s large hull makes it possible for a large onboard laboratory, with space for large analytical instruments and facilities. Since the first scientific operation conducted in the Nankai Trough in 2007, Chikyu made significant scientific achievements by IODP Expeditions. Those results are briefly introduced and show a future operation challenge with introducing Chikyu’s general features.

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.15, no.1, pp.中扉2p,35-87, 2009

著者

天本 奈々子 市川 光太郎 荒井 修亮

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.15, no.2, pp.149-157, 2009

著者

松尾 侑紀 市川 光太郎 溝端 紀子 荒井 修亮

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.19, no.1, pp.1-4, 2013

---

We examined relationship between vocal behavior of dugongs (<i>Dugong dugon</i>) and (1) time of day and (2) tide around Talibong Island, using passive acoustical observation. Also, we compared the results of several data and investigate whether the same behavior can be observed over different time of year. We used underwater sound data recorded in February and March 2004, November 2006 and January 2008 off southeast of Talibong Island and analyzed the number of calls detected in unit time in relation to time and tide. We also compared the result of the analysis among three months and investigated whether there was any difference. In terms of the effects of time, more calls were detected in nighttime than in daytime (p<0.05). In terms of the effects of tide, there were significant correlation between maximum tidal range and many calls were detected when tidal range was narrow. Our findings suggest that vocalization pattern of the dugongs is influenced by such external factors as time and tidal range.

著者

松田 秋彦 橋本 博公 谷口 裕樹 寺田 大介 三好 潤 溝口 弘泰 長谷川 勝男 世良 亘

出版者

海洋理工学会

雑誌

海洋理工学会誌 (ISSN:13412752)

巻号頁・発行日

vol.23, no.1, pp.47-51, 2017 (Released:2017-07-07)

参考文献数

12

---

As seaborne trade has greatly increased in recent years, it becomes more difficult to secure crew of ships. Therefore, it is an important issue how to realize unmanned robot ships which can automatically navigate without collisions even in congested waters. Although Rolls-Royce is planning to build a remotely controlled ship in 2020, standard control technology for unmanned ships has not been developed yet. Therefore an automatic collision avoidance system is discussed by carrying out not only computer simulations but also model experiments prior to the tests using actual vessels. For this purpose, the authors built an experimental system for the validation of automatic collision avoidance algorithm. In this paper, model experiments using multiple ships conducted at Marine Dynamics Basin at National Research Institute of Fisheries Engineering are introduced. Through comparisons with numerical simulations which the same algorithm for collision avoidance is implemented, it is found that there is a discrepancy in occurrence of collision in extremely congested situation.