Japan-equator XBT sections in late November 1989 and in early December 1991     

Jiro Yoshida  Hideo Sudo  Masaji Matsuyama  Yoshihiro Kurita  Yuji Mine 《Journal of Oceanography》1993,49(1):121-129

A comparison between Japan-equator XBT sections along 150°E in late November 1989 and along 140°E in early December 1991 is made. The warmest surface water above 29°C diminished to the south of 2–4°N and the surface mixed layer noticeably decreased in thickness in the equatorial region in December 1991; besides, the North Equatorial Countercurrent was intensified. This is considered to be a manifestation of changes in the surface layer of the western equatorial Pacific in the mature phase of El Niño.  相似文献   

Size-Fractionated Primary Production Estimated by a Two-Phytoplankton Community Model Applicable to Ocean Color Remote Sensing   总被引：3，自引：0，他引：3  

Takahiko?KamedaEmail author  Joji?Ishizaka 《Journal of Oceanography》2005,61(4):663-672

In order to estimate primary production from ocean color satellite data using the Vertical Generalized Production Model (VGPM; Behrenfeld and Falkowski, 1997), we propose a two-phytoplankton community model. This model is based on the two assumptions that changes in chlorophyll concentration result from changes of large-sized phytoplankton abundance, and chlorophyll specific productivity of phytoplankton tends to be inversely proportional to phytoplankton size. Based on the analysis of primary production data, P _opt ^B , which was one parameter in the VGPM, was modeled as a function of sea surface temperature and sea surface chlorophyll concentration. The two-phytoplankton community model incorporated into the VGPM gave good estimates in a relatively high productive area. Size-fractionated primary production was estimated by the two-phytoplankton community model, and P _opt ^B of small-sized phytoplankton was 4.5 times that of large-sized phytoplankton. This result fell into the ranges observed during field studies.  相似文献   

Long-term Sensor Drift Found in Recovered Argo Profiling Floats   总被引：5，自引：0，他引：5  

Eitarou?OkaEmail author 《Journal of Oceanography》2005,61(4):775-781

We recovered three Argo profiling floats after 2 to 2.5 years of operation, and recalibrated their temperature, conductivity, and pressure sensors. The results demonstrate that these floats exhibited a significant drift in salinity of −0.0074 to −0.0125, primarily due to the conductivity sensor drift. Combined with the recalibration result for another previously recovered float, the indication is that the negative salinity drift increases nearly in proportion to the operating period of floats. The increasing rate is −0.0041 (±0.0015) year⁻¹, which yields a salinity drift of −0.016 (±0.006) for the expected float lifetime of four years. The present result suggests that reducing the float surfacing time would improve the accuracy of the salinity measurements.  相似文献   

Simple determination of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) using solid-phase microextraction and gas chromatography-mass spectrometry     

Takushi?NikiEmail author  Taiki?Fujinaga  Mariyo?F.?Watanabe  Junji?Kinoshita 《Journal of Oceanography》2004,60(5):913-917

Solid-phase microextraction (SPME) is a simple, sensitive and less destructive method for the determination of dimethylsulfide (DMS) in seawater. Combined with detection by gas chromatography-mass spectrometry (GC-MS), the method had sufficient sensitivity (minimum detectable concentration of DMS was 0.05 nM), and practical levels of reproducibility (relative standard deviation ≤7%) and linearity (r ² > 0.995) over a wide concentration range (0.5 to 910 nM). The protocol developed was applied to a Sagami Bay water sample to determine concentrations of DMS and DMSP, and in situ DMSP-lyase activity.  相似文献   

Eddy Shedding from the Kuroshio Bend at Luzon Strait   总被引：16，自引：1，他引：16  

Yinglai?JiaEmail author  Qinyu?Liu 《Journal of Oceanography》2004,60(6):1063-1069

TOPEX/POSEDIENT-ERS satellite altimeter data along with the mean state from the Parallel Ocean Climate Model result have been used to investigate the variation of Kuroshio intrusion and eddy shedding at Luzon Strait during 1992–2001. The Kuroshio penetrates into the South China Sea and forms a bend. The Kuroshio bend varies with time, periodically shedding anticyclonic eddies. Criteria of eddy shedding are identified: 1) When the shedding event occurs, there are usually two centers of high Sea Surface Height (SSH) together with negative geostrophic vorticity in the Kuroshio Bend (KB) area. 2) Between the two centers of high SSH there usually exists positive geostrophic vorticity. These criteria have been used to determine the eddy shedding times and locations. The most frequent eddy shedding intervals are 70, 80 and 90 days. In both the winter and summer monsoon period, the most frequent locations are 119.5°E and 120°E, which means that the seasonal variation of eddy shedding location is unclear.  相似文献   

Radiocarbon anomaly found in aquicultural scallops suspended in coastal sea     

Shizuo Tsuncgai  Manabu Tsuzuki  Shuichi Watanate  Naohiro Yoshida 《Journal of Oceanography》1993,49(1):31-37

The radiocarbon content of scallops aquiculturally suspended and grown in coastal sea, Funka Bay, were determined. While the ¹⁴C values of carbonate shells coincided with that of ambient seawater, those of soft tissues were smaller than the seawater value and varied rather widely. To clarify the cause of this variation, we further divided the soft tissues of composite scallops into each organ and determined their radiocarbon content. The results show that only the ¹⁴C of adductor (Kaibashira in Japanese) of scallops was significantly smaller than the others, those of gill and mantle coincided to that of seawater. This strange finding cannot be explained by the present knowledge on the dietary sources of scallops and the present theory of isotopic fractionation, unless any unknown physiological or oceanographical process determines the radiocarbon content of the organisms.  相似文献   

Physical oceanography   总被引：2，自引：0，他引：2  

K. Yoshida  K. Takano  T. Teramoto  Y. Toba  Y. Nagata  K. Kajiura  T. Nan'nichi  N. Iwata  T. Takahashi  M. Chaen  T. Tabata 《Journal of Oceanography》1971,27(6):248-264

  相似文献   

Geodynamics of the deep sedimentary basin of the Caspian Sea region: paragenetic correlation of seismicity and mud volcanism     

Ibrahim?Guliev  Behrouz?PanahiEmail author 《Geo-Marine Letters》2004,24(3):169-176

In this paper we analyze seismic regime and earthquake depth distribution and correlation of seismicity and mud volcanism in the Azerbaijan and the Caspian Sea region. For the present region we have calculated accurate source locations, seismic activity, earthquake repetition and released earthquake energy parameters. It is shown that the active tectonic processes in the region are concentrated within the thick sedimentary cover that we consider as a general source of contemporary stress and a main structural element responsible for the origin of regional earthquakes. The correlation of seismicity and mud volcanism is of paragenetic character.  相似文献   

Positioning accuracy of the Data Collection Platform through the translocation and orbit correction method     

Toshiharu Kakihara  Jiro Segawa 《Journal of Oceanography》1989,45(1):1-10

A new algorithm has been developed to determine the position of a Data Collection Platform (DCP) that is used for the ARGOS Localization and Data Collection System. The algorithm uses an estimation scheme to correct the orbital parameters to achieve accurate positioning of the NOAA meteorological satellite. It is proved that the positioning accuracy of a DCP by the method of orbital Paramater correction is superior to the translocation method.Positioning of a moving DCP was also attempted by installing a DCP on board a vessel.  相似文献   

Oil-generation kinetics for organic facies with Type-II and -IIS kerogen in the Menilite Shales of the Polish Carpathians     

M.D. Lewan  M.J. Kotarba  D. Wi?c?aw 《Geochimica et cosmochimica acta》2006,70(13):3351-3368

The Menilite Shales (Oligocene) of the Polish Carpathians are the source of low-sulfur oils in the thrust belt and some high-sulfur oils in the Carpathian Foredeep. These oil occurrences indicate that the high-sulfur oils in the Foredeep were generated and expelled before major thrusting and the low-sulfur oils in the thrust belt were generated and expelled during or after major thrusting. Two distinct organic facies have been observed in the Menilite Shales. One organic facies has a high clastic sediment input and contains Type-II kerogen. The other organic facies has a lower clastic sediment input and contains Type-IIS kerogen. Representative samples of both organic facies were used to determine kinetic parameters for immiscible oil generation by isothermal hydrous pyrolysis and S₂ generation by non-isothermal open-system pyrolysis. The derived kinetic parameters showed that timing of S₂ generation was not as different between the Type-IIS and -II kerogen based on open-system pyrolysis as compared with immiscible oil generation based on hydrous pyrolysis. Applying these kinetic parameters to a burial history in the Skole unit showed that some expelled oil would have been generated from the organic facies with Type-IIS kerogen before major thrusting with the hydrous-pyrolysis kinetic parameters but not with the open-system pyrolysis kinetic parameters. The inability of open-system pyrolysis to determine earlier petroleum generation from Type-IIS kerogen is attributed to the large polar-rich bitumen component in S₂ generation, rapid loss of sulfur free-radical initiators in the open system, and diminished radical selectivity and rate constant differences at higher temperatures. Hydrous-pyrolysis kinetic parameters are determined in the presence of water at lower temperatures in a closed system, which allows differentiation of bitumen and oil generation, interaction of free-radical initiators, greater radical selectivity, and more distinguishable rate constants as would occur during natural maturation. Kinetic parameters derived from hydrous pyrolysis show good correlations with one another (compensation effect) and kerogen organic-sulfur contents. These correlations allow for indirect determination of hydrous-pyrolysis kinetic parameters on the basis of the organic-sulfur mole fraction of an immature Type-II or -IIS kerogen.  相似文献