CO<Subscript>2</Subscript> Flux Measurements over the Sea Surface by Eddy Correlation and Aerodynamic Techniques     

Toru?Iwata  Keiko?Yoshikawa  Katsutoshi?Nishimura  Yoshihisa?Higuchi  Takao?Yamashita  Shigeru?Kato  Eiji?OhtakiEmail author 《Journal of Oceanography》2004,60(6):995-1000

The measurements of the vertical transport of CO₂ were carried out over the Sea of Japan using the specially designed pier of Kyoto University on September 20 to 22, 2000. CO₂ fluxes were measured by the eddy correlation and aerodynamic techniques. Both techniques showed comparable CO₂ fluxes during sea breeze conditions: −0.001 to −0.08 mg m⁻²s⁻¹ with the mean of −0.05 mg m⁻²s⁻¹. This means that the measuring site satisfies the fetch requirement for meteorological observations under sea breeze conditions. Moreover, the eddy diffusivity coefficient used in the aerodynamic technique is found to be consistent with the coefficient used in the eddy correlation technique. The present result leads us to conclude that the aerodynamic technique may be applicable to underway CO₂ flux measurements over the ocean and may be used in place of the bulk technique. The important point is the need to maintain a measuring accuracy of CO₂ concentration difference of the order of 0.1 ppmv on the research vessels or the buoys.  相似文献   

Rifting to Spreading Process along the Northern Continental Margin of the South China Sea   总被引：7，自引：0，他引：7  

Kido  Yukari  Suyehiro  Kiyoshi  Kinoshita  Hajimu 《Marine Geophysical Researches》2001,22(1):1-15

Understanding the development from syn-rift to spreading in the South China Sea (SCS) is important in elucidating the western Pacific's tectonic evolution because the SCS is a major tectonic constituent of the many marginal seas in the region. This paper describes research examining the transition from rifting to spreading along the northern margin of the SCS, made possible by the amalgamation of newly acquired and existing geophysical data. The northernmost SCS was surveyed as part of a joint Japan-China cooperative project (JCCP) in two phases in 1993 and 1994. The purpose of the investigation was to reveal seismic and magnetic characteristics of the transitional zone between continental crust and the abyssal basin. Compilation of marine gravity and geomagnetic data of the South China Sea clarify structural characteristics of its rifted continental and convergent margins, both past and present. Total and three component magnetic data clearly indicate the magnetic lineations of the oceanic basin and the magnetic characteristics of its varied margins. The analyses of magnetic, gravity and seismic data and other geophysical and geological information from the SCS led up to the following results: (1) N-S direction seafloor spreading started from early Eocene. There were at least four separate evolutional stages. Directions and rates of the spreading are fluctuating and unstable and spreading continued from 32 to 17 Ma. (2) The apparent difference in the present tectonism of the eastern and western parts of Continent Ocean Boundary (COB) implies that in the east of the continental breakup is governed by a strike slip faulting. (3) The seismic high velocity layer in the lower crust seems to be underplated beneath the stretched continental crust. (4) Magnetic anomaly of the continental margin area seems to be rooted in the uppermost sediment and upper part of lower crust based on the tertiary volcanism. (5) Magnetic quiet zone (MQZ) anomaly in the continental margin area coincides with COB. (6) The non-magnetic or very weakly magnetized layer is probably responsible for MQZ. One of the causes of demagnetization of the layer is due to hydrothermal alteration while high temperature mantle materials being underplated. Another explanation is that horizontal sequences of basalt each with flip-flop magnetization polarity cancel out to the resultant magnetic field on the surface. We are currently developing a synthetic database system containing datasets of seismicity, potential field data, crustal and thermal structures, and other geophysical data to facilitate the study of past, contemporary and future changes in the deep sea environment around Japan; i.e. trench, trough, subduction zones, marginal basins and island arcs. Several special characteristics are an object-oriented approach to the collection and multi-faceted studies of global data from a variety of sources.  相似文献   

Latitudinal distribution and origin of particulate silica in the surface water of the North Pacific     

Katsutoshi Kido 《Marine Chemistry》1974,2(4):277-285

The concentrations of particulate silica and inorganic suspended matter in the surface water of the North Pacific were determined. The concentration of particulate silica depends on latitude, and increases with increasing degree of the north latitude. The concentration of inorganic suspended matter shows a similar distribution pattern, but it is of much smaller magnitude. There exists a high positive correlation between the concentrations of particulate silica and nutrients. On the other hand, a weak negative correlation is found between the concentrations in surface seawater of particulate silica and radioactive ²¹⁰Pb which originate chiefly from precipitation and dry fallout. This evidence suggests that the particulate silica in the sea is mainly of biogenic origin and the contribution of nonbiogenic silica, i.e., of terrestrial origin, is small.  相似文献   

The mineralogy and provenance of deep-sea sediments recovered by gravity corer off Sierra Leone,West Africa     

Hakuyu Okada  Katsutoshi Tomita  E. J. W. Jones 《Journal of Oceanography》1981,37(4):201-211

The mineralogy of eight gravity cores recovered between Sierra Leone and 25°W longitude has been examined in an investigation of the provenance of the recent sediments in the eastern Equatorial Atlantic. X-ray analyses show that the principal mineral components are calcite, quartz, feldspar, kaolinite, illite and montmorillonite. One core taken from the upper continental slope off Freetown also contains gibbsite, a product of intense tropical weathering. Biogenic material forms the dominant component of most sections of the cores but it is clear from the abundance of quartz, kaolinite and freshwater diatoms that an aeolian supply of continental detritus has been important in the formation of the recent sediment cover. A significant contribution from volcanic sources can be recognised to the west of the Sierra Leone Rise. The occurrence of calcareous turbidites in two cores from the St. Paul's Fracture Zone and from the basin west of the Sierra Leone Rise appears to be a reflection of recent tectonic activity.  相似文献   

Continuous wavelet-like filter for a spherical surface and its application to localized admittance function on Mars     

Motoyuki Kido  David A. Yuen 《Physics of the Earth and Planetary Interiors》2003,135(1):1-16

We have developed a 2D isotropic continuous wavelet-like transform for a spherical surface. The transform is simply defined as the surface convolution between the original field and a kernel, based on the zeroth-order Bessel function with a spherical correction. This spherical correction violates the geometric similarity for the various scales of the kernels, which becomes more apparent at longer wavelengths. We found numerically that this transform is practically equivalent to a Gaussian bandpass filter in the spherical harmonic domain. We have applied this wavelet-like transform on the recently acquired Martian gravity and topography fields. Using a ratio constructed locally from these two fields, we have constructed a map describing the lateral variations of the localized admittance function on Mars.  相似文献   

Ningaloo Niño simulated in the CMIP5 models     

Shoichiro Kido  Takahito Kataoka  Tomoki Tozuka 《Climate Dynamics》2016,47(5-6):1469-1484

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Characteristics of ionic components in precipitation in Kitakyushu City,Japan     

Yasuhiro Yamato  Takashi Yamada  Kozo Kido 《Journal of Atmospheric Chemistry》1993,17(4):325-337

Precipitation samples were collected by filtrating bulk sampler in Kitakyushu City, Japan, from January 1988 to December 1990. Volume weighted annual mean of pH was 4.93, but the pH distribution indicated that most probable value lay in the range pH 6.0–6.4. Volume weighted annual mean concentrations of major ionic components were as follows; SO ₄ ^2– : 84.2, NO ₃ ^– : 28.1, Cl^–: 86.3, NH ₄ ⁺ : 45.5, Ca²⁺: 63.3, Mg²⁺: 27.0, K⁺: 3.4, Na⁺: 69.0 µ eq l^–1. The highest concentrations of these ionic components were observed in winter and the lowest occurred in the rainy season. The ratio of ex-SO ₄ ^2– /NO ₃ ^– exhibited the lowest ratio in summer, and the highest ratio in winter. Good correlations were obtained between Cl^– and Na⁺, ex-SO ₄ ²⁺ and ex-Ca²⁺, NO ₃ ^– and ex-Ca²⁺, and NH ₄ ⁺ and ex-SO ₄ ^2– , respectively. However, no correlation between Cl^– and Na⁺ with Ca²⁺ was observed. The relationship of H⁺ with (ex-SO ₄ ^2– + NO ₃ ^– ) - (ex-Ca²⁺ + NH ₄ ⁺ ) indicated positive correlation.  相似文献   

Clinoamphibole lamellae in diopside of garnet lherzolite from Alpe Arami,Bellinzona, Switzerland     

Yoshiaki Yamaguchi  Junji Akai  Katsutoshi Tomita 《Contributions to Mineralogy and Petrology》1978,66(3):263-270

Porphyroclastic diopside in garnet lherzolite from Alpe Arami, Bellinzona, Switzerland includes optically-visible clinoamphibole lamellae with a composition intermediate between pargasite and edenite. X-ray and electron microscopic observations show that the diopside crystal contains sub-microscopic thin clinoamphibole lamellae parallel to (010), which have coherent interfaces to the host. A kind of planar defect parallel to (010) in clinopyroxene structure, as suggested by Chisholm (1973), is shown here to correspond to intercalation of a 9 Å lattice fringe of double-chain structure in the electron micrograph of the diopside. The thin clinoamphibole lamellae are observed to be segregated domains consisting of two and more 9 Å fringes.From the chemical characteristics and textural relations of the development of such clinoamphiboles, the chemical change required to form them is considered to have been caused principally by decreasing solubility of atoms such as Na, Al and Cr in clinopyroxene structure during the retrogressive reequilibration. Also, a possibility of finite solid solution of clinoamphibole in clinopyroxene is discussed.  相似文献   

Effect of open gap in coastal forest on tsunami run-up—investigations by experiment and numerical simulation     

Nguyen Ba Thuy  Katsutoshi Tanimoto  Norio Tanaka  Kenji Harada  Kosuke Iimura 《Ocean Engineering》2009,36(15-16):1258-1269

The objective of this study is to investigate the effects of an open gap, such as a road, in a coastal forest on tsunami run-up. A numerical model based on two-dimensional nonlinear long-wave equations was developed to account for the effects of drag and turbulence induced shear forces due to the presence of vegetation. Experiments were conducted on a forest simulated with vertical cylinders by changing the gap width. The numerical model was validated in good agreement with the experimental results. The numerical model was then applied to a wide forest of Pandanus odoratissimus, a tree species that is a dominant coastal vegetation on a sand dune in South and Southeast Asia. The effect of vertical stand characteristics of P. odoratissimus with aerial roots was considered on the drag resistance. A straight open gap perpendicular to the shoreline was used to investigate the effect of gap width. As the gap width increases, the flow velocity at the end of the open gap first increases, reaches a maximum, and then decreases, while the run-up height increases monotonously. The maximum velocity in the present condition is 1.7 times the maximum velocity without a coastal forest. The effects of different gap arrangements in the forest on tsunami run-up were also investigated in this paper. The flow velocity at the end of an open gap can be reduced by a staggered arrangement.  相似文献   

Dynamics of pelagic variables in two contrasting coastal systems in the western Hokkaido coast off Otaru port,Japan     

Julius I. Agboola  Mario Uchimiya  Isao Kudo  Kazuo Kido  Masato Osawa 《Estuarine, Coastal and Shelf Science》2010,86(3):477-484

Human impact on adjacent coastal waters, leading to alteration in nutritional environment and hence affecting phytoplankton biomass (Chlorophyll a), will probably be enhanced by the nearby presence of ports. The main goal of this study is to assess the influence of nearby presence of port on phytoplankton biomass build-up and the physical–chemical environmental characteristics in two contrasting coastal systems (Otaru port, S-IN and an exposed coastal area, S-OUT) in the western Hokkaido coast off Otaru port, Japan. Sampling was conducted on “bi-weekly and monthly” basis during the period of September 2006–December 2007 and data comprising 11 pelagic variables were obtained. In most instance, phytoplankton biomass, nutrients' (NH₄, NO₃, PO₄, and Si(OH)₄) concentrations and nutrients' molar ratios were higher at the Otaru port location. Physical parameters (temperature, salinity, hydrogen ion concentration (pH), photosynthetically active radiation (PAR) and dissolved oxygen, (DO)) were not significantly different (P > 0.05) between the two locations. With the exception of salinity, pH and DIC, all variables measured showed significant variation (P < 0.05) with season. While the coefficient of variation (CV) of physical parameters and phytoplankton biomass were relatively higher in Otaru port location (S-IN), the exposed coastal location (S-OUT) showed a higher variation in chemical parameters. Other variables showed different patterns between the two locations. We conclude that ports, due to its activities and restricted circulation favour high nutrient loading and phytoplankton biomass build-up in adjacent coastal systems, thus, suggesting the need for continuous field observation data in order to advance our knowledge on possible future human impact on coastal environment and the need to monitor and control port activities.  相似文献