Corrigendum to “Climatological mean and decadal change in surface ocean pCO₂, and net sea–air CO₂ flux over the global oceans” [Deep Sea Res. II 56 (2009) 554–577]     

Taro Takahashi  Stewart C. Sutherland  Rik Wanninkhof  Colm Sweeney  Richard A. Feely  David W. Chipman  Burke Hales  Gernot Friederich  Francisco Chavez  Christopher Sabine  Andrew Watson  Dorothee C.E. Bakker  Ute Schuster  Nicolas Metzl  Hisayuki Yoshikawa-Inoue  Masao Ishii  Takashi Midorikawa  Yukihiro Nojiri  Arne Krtzinger  Tobias Steinhoff  Mario Hoppema  Jon Olafsson  Thorarinn S. Arnarson  Bronte Tilbrook  Truls Johannessen  Are Olsen  Richard Bellerby  C.S. Wong  Bruno Delille  N.R. Bates  Hein J.W. de Baar 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2075-2076

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Seasonal and vertical distribution of Aurelia aurita polyps on a pylon in the innermost part of Tokyo Bay     

Haruto Ishii  Kiyonori Katsukoshi 《Journal of Oceanography》2010,66(3):329-336

Natural aggregations of Aurelia aurita polyps were found by direct observation during SCUBA diving on the surface of a pylon in the innermost part of Tokyo Bay, Japan, and changes in polyp abundance with depth were examined from November 2000 to December 2001. Most polyps were observed on substrates in the layer within 1 m from the bottom. Substrates in the upper layer were mainly occupied by other sessile organisms such as the blue mussel Mytilus galloprovincialis, implying that A. aurita polyps may be exposed to interspecific competition for space with other organisms, especially during spring and summer. The bottom layer, especially within 1 m from the bottom, was characterized by summer hypoxia and low recruitment and growth of other sessile organisms such as mussels, resulting in abundant settlement and high survival of A. aurita polyps, which are tolerant of near-hypoxic conditions. It is considered that the occurrence of hypoxic waters due to eutrophication contributes directly to the recruitment of polyps and the consequent production of A. aurita medusae in the following year.  相似文献   

Accidents due to oxygen deficiency and methane gas blow-off in Tokyo area,Japan     

Hisato Hayashi  Motomu Ishii 《Environmental Geology》1989,13(2):167-177

The groundwater leve in the Tokyo area had declined to about 60 m below the surface because of excess withdrawal of groundwater from various aquifers. Many construction workers died due to oxygen deficiency at construction sites from 1960 to 1980, the period of decreasing groundwater level. The compressed air in pneumatic foundation construction sites passed easily through the aquifer, and the oxygen in it was consumed by ferrous ions oxidizing to ferric ions. During periods of high barometric pressure, atmospheric air penetrates into the strata and it is deoxygenated there. Suffocation occurred not only at construction sites in underground excavations, but also in residences in Tokyo. Such acidents have become less frequent with recovery of the pore-water pressure in aquifers, which has accompanied the recovery of the groundwater level since 1972.With the recovery of the pore-water pressure and the groundwater level in the aquifer, fires and explosions resulting from gushes of methane have occurred in Tokyo lowlands since 1973. These blow-off gases are classified into two types: Kameido and Asakusa.The gas of the Kameido type originates from the Kazusa Group and migrates into upper alluvial deposits or Pleistocene sediments because of the recovery of pore-water pressure in the Kazusa Group. The gas of the Asakusa type formed from the air that penetrated the aquifers during the period of low groundwater level. Methane was produced by the depletion of oxygen accumulated in alluvial deposits and Pleistocene sediments. This gas blows off through wells in alluvial deposits and Pleistocene sediments at times of low barometric pressure. Accidents of the Asakusa type will not happen when the groundwater level and pore-water pressure in alluvial and Pleistocene sediments is restored to previous levels.  相似文献   

Measurement of bubble size distributions in vesiculated rocks with implications for quantitative estimation of eruption processes   总被引：1，自引：0，他引：1  

Atsushi Toramaru   《Journal of Volcanology and Geothermal Research》1990,43(1-4)

This paper outlines methods for determining a bubble size distribution (BSD) and the moments of the BSD function in vesiculated clasts produced by volcanic eruptions. It reports the results of applications of the methods to 11 natural samples and discusses the implications for quantitative estimates of eruption processes. The analysis is based on a quantitative morphological (stereological) method for 2-dimensional imaging of cross-sections of samples. One method determines, with some assumptions, the complete shape of the BSD function from the chord lengths cut by bubbles. The other determines the 1st, 2nd and 3rd moments of distribution functions by measurement of the number of bubbles per unit area, the surface area per unit volume, and the volume fraction of bubbles. Comparison of procedures and results of these two distinct methods shows that the latter yields rather more reliable results than the former, though the results coincide in absolute and relative magnitudes. Results of the analysis for vesiculated rocks from eleven subPlinian to Plinian eruptions show some interesting systematic correlations both between moments of the BSD and between a moment and the eruption column height or the SiO₂ content of magma. These correlations are successfully interpreted in terms of the nucleation and growth processes of bubbles in ascending magmas. This suggests that bubble coalescence does not predominate in sub-Plinian to Plinian explosive eruptions. The moment-moment correlations put constraints on the style of the nucleation and growth process of bubbles. The scaling argument suggests that a single nucleation event and subsequent growth with any kind of bubble interaction under continuous depressurization, which leads to an intermediate growth law between the diffusional growth ( ) at a constant depressurization rate and the Ostwald ripening ( ) under a constant pressure, where R_m and t are the mean radius of bubble and the effective time of diffusion respectively, occurred in the eruptions. It is emphasized that the BSD in vesiculated rocks from terrestrial volcanoes can be used to estimate quantitatively eruption processes such as the initial saturation pressure and magma ascent velocity in a volcanic conduit.  相似文献   

Fine structure beneath the Tohoku district, northeastern Japan arc, as derived by an inversion of P-wave arrival times from local earthquakes     

Akiko Horie Hasemi  Hiroshi Ishii  Akio Takagi 《Tectonophysics》1984,101(3-4)

Three dimensional P-wave velocity structure beneath the Tohoku district, northeastern Japan arc, is investigated by an inversion of arrival times from local earthquakes using the method originally due to Aki and Lee (1976).In the crust (0–32 km depth) a low-velocity region is found along the volcanic front and its vicinity. Velocities at depths of 32–65 km are low beneath the regions where many Quaternary volcanoes and geothermal areas are distributed. In the region deeper than 65 km, the subduction of the Pacific plate is clearly revealed, and the mantle structure above the descending plate is rather uniform. These features suggest that volcanic activities have relation to the upper mantle structure. The results obtained in this study will be helpful in investigating the mechanism of magma generation in a subduction zone.  相似文献   

Rockfall hazard in the Daisekkei Valley, the northern Japanese Alps, on 11 August 2005     

Yoshihiko Kariya  Go Sato  Kuniyasu Mokudai  Jiro Komori  Masaki Ishii  Ryoko Nishii  Yosuke Miyazawa  Noriko Tsumura 《Landslides》2007,4(1):91-94

This paper describes a rockfall event in the Daisekkei Valley of Mount Shirouma-dake (2,932 m), the northern Japanese Alps. The rockfall occurred on a steep cliff comprising well-jointed felsites and produced debris of ≥8,000 m³. Most debris was deposited on an elongated snowpatch located immediately beneath the cliff, and it caused casualties among people who were trekking along a trail on the snowpatch. Additionally, a large rock block slipped 1 km on the snowpatch. The rockfall could have been due to the differential retreat of the rockwall, which contains areas of high- and low-density joints. Seasonal and diurnal freeze–thaw activities and snow avalanches and wash appear to be important factors responsible for the retreat. Although some rock blocks that can collapse further remain on the rockwall, the position of the mountain trail in the Daisekkei Valley is fixed. Fundamental reform of tourism systems for climbers, including education on natural hazards, is required.  相似文献   

Strain and tilt changes measured during a water injection experiment at the Nojima Fault zone, Japan   总被引：2，自引：0，他引：2  

Kunio Fujimori  Hiroshi Ishii  Atsushi Mukai  Shigeru Nakao  Shigeo Matsumoto  Yasuhiro Hirata 《Island Arc》2001,10(3-4):228-234

Abstract In order to make geophysical and geological investigations of the Nojima Fault on Awaji Island, Japan, three boreholes measuring 1800 m, 800 m and 500 m deep were drilled into the fault zone. The fault is one of the seismic source faults of the 1995 Hyogo-ken Nanbu earthquake of M 7.2. A new multicomponent borehole instrument was installed at the bottom of the 800 m borehole and continuous observations of crustal strain and tilt have been made using this instrument since May 1996. A high-pressure water injection experiment within the 1800 m borehole was done in February and March 1997 to study the geophysical response, behavior, permeability, and other aspects of the fault zone. The injection site was located approximately 140 m horizontally and 800 m vertically from the instrument. Associated with the water injection, contraction of approximately 0.7 × 10⁻⁷ str (almost parallel to the fault) and tilt of approximately 1 × 10^-7 rad in the sense of upheaval toward the injection site were observed. In addition to these controlled experiments, the strainmeter and tiltmeter also recorded daily variations. We interpret strain and tilt changes to be related to groundwater discharge and increased ultra-micro seismicity induced by the injected water.  相似文献   

Mesozoic radiolarians and radiolarian-bearing sequences in the circum-Pacific regions: A report of the symposium-'Radiolarians and Orogenic Belts'     

Atsushi  Matsuoka  Yoshiaki  Aita  Munasri  Koji  Wakita  Gaoping  Shen  Hiroshi  Ujilé  Katsuo  Sashida  Valentina S.  Vishnevskaya  Nkita Y.  Bragin Fabrice  Cordey 《Island Arc》1996,5(2):203-213

Abstract This paper contains extended abstracts of the seven papers presented at the symposium 'Radiolarians and Orogenic Belts' held at the seventh meeting of the International Association of Radiolarian Paleontologists (INTERRAD). Important results of the symposium include the following: (1) Upper Paleozoic and Mesozoic cherts are widely distributed within accretionary complexes in the circum-Pacific orogenic belt. Radiolarian dating reveals that long durations of chert sedimentation in a pelagic environment are recorded on both sides of Pacific-rim accretionary complexes (e.g. New Zealand, Japan, Russian Far East, Canadian Cordillera). (2) Triassic radiolarian faunas from New Zealand and the Omolon Massif, northeast Siberia are similar in composition and are characterized by the absence of typical Tethyan elements. This suggests that radiolarian faunal provincialism may have been established as early as the Triassic. High-latitude radiolarian taxa exhibit a bi-polar distribution pattern. (3) The Lower Triassic interval in chert dominant pelagic sequences is mechanically weaker than other levels and acted as a décollement in accretionary events. This lithologic. contrast in physical property is considered to reflect radiolarian evolution, such as the end-Permian mass extinction.  相似文献   

Precise determination of cooling times of post-flare loops from the detailed comparison between Hα and soft X-ray images     

Suguru Kamio  Hiroki Kurokawa  Takako T. Ishii 《Solar physics》2003,215(1):127-146

A detailed study of the evolution and cooling process of post-flare loops is presented for a large X9.2 solar flare of 2 November 1992 by using H images obtained with Domeless Solar Telescope at Hida Observatory and soft X-ray images of Yohkoh Soft X-ray Telescope (SXT). The detailed analysis with a new method allows us to determine more precise values of the cooling times from 10⁷ K to 10⁴ K plasma in the post-flare loops than in previous works. The subtraction of sequential images shows that soft X-ray dimming regions are well correlated to the H brightening loop structure. The cooling times between 10⁷ K and 10⁴ K are defined as the time difference between the start of soft X-ray intensity decrease and the end of H intensity increase at a selected point, where the causal relation between H brightening and soft X-ray dimming loops is confirmed. The obtained cooling times change with time; about 10 min at the initial stage and about 40 min at the later stage. The combined conductive and radiative cooling times are also calculated by using the temperature and density obtained from SXT data. Calculated cooling times are close to observed cooling times at the beginning of the flare and longer in the later stage.  相似文献   

Solar Wind Speed and Expansion Rate of the Coronal Magnetic Field in Solar Maximum and Minimum Phases     

Hakamada  Kazuyuki  Kojima  Masayoshi  Tokumaru  Munetoshi  Ohmi  Tomoaki  Yokobe  Atsushi  Fujiki  Ken'ichi 《Solar physics》2002,207(1):173-185

Relationships between solar wind speed and expansion rate of the coronal magnetic field have been studied mainly by in-ecliptic observations of artificial satellites and some off-ecliptic data by Ulysses. In this paper, we use the solar wind speed estimated by interplanetary scintillation (IPS) observations in the whole heliosphere. Two synoptic maps of SWS estimated by IPS observations are constructed for two Carrington rotations CR 1830 and 1901; CR 1830 starting on the 11th of June, 1990 is in the maximum phase of solar activity cycle and CR 1901 starting on the 29th of September, 1995 is in the minimum phase. Each of the maps consist of 64800 (360×180) data points. Similar synoptic maps of expansion rate of the coronal magnetic field (RBR) calculated by the so-called potential model are also constructed under a radial field assumption for CR 1830 and CR1901. Highly significant correlation (r=–0.66) is found between the SWS and the RBR during CR1901 in the solar minimum phase; that is, high-speed winds emanate from photospheric areas corresponding to low expansion rate of the coronal magnetic field and low speed winds emanate from photospheric areas of high expansion rate. A similar result is found during CR 1830 in solar maximum phase, though the correlation is relatively low (r=–0.29). The correlation is improved when both the data during CR 1830 and CR 1901 are used together; the correlation coefficient becomes –0.67 in this case. These results suggest that the correlation analysis between the SWS and the RBR can be applied to estimate the solar wind speed from the expansion rate of the coronal magnetic field, though the correlation between them may depend on the solar activity cycle. We need further study of correlation analysis for the entire solar cycle to get an accurate empirical equation for the estimation of solar wind speed. If the solar wind speed is estimated successfully by an empirical equation, it can be used as an initial condition of a solar wind model for space weather forecasts.  相似文献