Potential of mosques to serve as evacuation shelters for foreign Muslims during disasters: a case study in Gunma,Japan     

Kotani  Hitomu  Tamura  Mari  Li  Jiayue  Yamaji  Eiji 《Natural Hazards》2021,109(2):1407-1423

Natural Hazards - Foreigners tend to be vulnerable to disasters due to religious and cultural differences. In Japan, Muslim foreign residents, who are minorities, likely face difficulties in terms...  相似文献   

Global assessment of the effectiveness of adaptation in coastal areas based on RCP/SSP scenarios     

Tamura  Makoto  Kumano  Naoko  Yotsukuri  Mizuki  Yokoki  Hiromune 《Climatic change》2019,152(3-4):363-377

Climatic Change - The objective of this study is to assess the global impact of sea level rise and to evaluate the effectiveness of adaptation. Global areas of inundation due to sea level rise are...  相似文献   

Postglacial stratigraphic evolution of a current-influenced sandy shelf: offshore Kujukuri strandplain,central Japan     

Naohisa Nishida  Taku Ajioka  Ken Ikehara  Rei Nakashima  Hajime Katayama  Tomoyuki Sato  Seishiro Furuyama  Toru Tamura 《Sedimentology》2020,67(1):559-575

Sandy shelf sediments are important elements of clastic sedimentary systems because of their wide distribution in the geological record and their significance as hydrocarbon reservoirs. Although many studies have investigated shelf sediments influenced by waves or tidal currents, little is known about shelf sediments influenced by oceanic currents, particularly their lithofacies characteristics and stratigraphic evolution. This study investigated the stratigraphic evolution of shelf sediments off the Kujukuri strandplain facing the Pacific Ocean, which is influenced by the strong Kuroshio Current. Sediment cores were obtained from six locations on the Kujukuri shelf (34 to 124 m water depth) using a vibrocorer. The dominant lithofacies is mud-free sand with low-angle cross-lamination associated with alternating beds of finer and coarser sand with cross-lamination. These display depositional processes influenced by storm waves and the Kuroshio Current, respectively. This finding is consistent with the previously presented modern and historical observations of the Kuroshio Current and estimates of the storm-wave base. Radiocarbon dates show that the sediment succession formed during the last transgressive and highstand stages after 13·1 ka. The depositional processes during the stages represent a transition from storm waves with abundant sediment supply to both storm waves and the Kuroshio Current with sediment starvation mainly due to its trapping in the strandplain. Comparison to other Holocene–Modern shelf systems suggests that the sandy shelf successions are strongly influenced by oceanic currents under conditions of limited riverine input and open coastal geometry. The resultant sand-dominated succession is characterized by reversal of the proximal to distal grain-size trend compared to the fining for most other recognized wave/storm-dominated shelf successions. This is because of seaward increase in the influence of the Kuroshio Current. Thus, shelf deposits are naturally complex, and these may be further complicated by the additional influence of oceanic currents above the usual wave-dominated and tide-dominated end members.  相似文献   

Upwelling plumes in sagami bay and adjacent water around the Izu Islands,Japan     

Masayuki Takahashi  Isao Koike  Takashi Ishimaru  Toshiro Saino  Ken Furuya  Yoshihiko Fujita  Akihiko Hattori  Shun-ei Ichimura 《Journal of Oceanography》1980,36(4):209-216

Water plumes, 20 km long or less, identified by low temperature, high salinity and high nutrient concentrations, were observed on the eastern side of Izu Islands where the Kuroshio Current or its branch flowed eastward. The T-S diagrams and the vertical profiles of oceanographic variables indicated that the water plumes resulted from the upwelling of subsurface water. A newly formed plume, characterized by a sharp temperature front and high nutrient concentrations, contained less chlorophyll than did old plumes. It is suggested that the upwelling plumes are maintained for a period long enough to allow luxuriant growth of phytoplankton.  相似文献   

Outflow of the Intermediate Oyashio Water from Sagami Bay to the Shikoku Basin     

Yoshihiko Sekine  Keita Uchiyama 《Journal of Oceanography》2002,58(4):531-537

Since the Intermediate Oyashio Water (IOW) gradually accumulates in Sagami Bay, it can reasonably be supposed that the IOW also flows out from Sagami Bay, even though it may be altered by mixing with other waters. We have occasionally observed a water less than 34.2 psu with a potential density of 26.8 at the southeastern area off Izu Peninsula in July 1993 by the training vessel Seisui-maru of Mie University. Observational data supplied by the Japan Meteorological Agency and the Kanagawa Prefectural Fisheries Experimental Station show that the IOW of less than 34.1 psu was observed at northern stations of the line PT (KJ) off the Boso Peninsula and to the east of Oshima in the late spring 1993. Based upon these observations, it is concluded that the IOW flows out from Sagami Bay into the Shikoku Basin along southeastern area off the Izu Peninsula. The less saline water (<34.2 psu) was also observed to the west of Miyake-jima during the same cruise, and the westward intrusion of IOW from south of the Boso Peninsula to the Shikoku Basin through the gate area of the Kuroshio path over the Izu Ridge was detected. This event indicated that the IOW branched south of the Boso Peninsula and flowed into Sagami Bay and/or into the gate area over the Izu Ridge. The southward intrusion of IOW into the south of the Boso Peninsula is discussed in relation to the latitudinal location of the main axes of the Kuroshio and the Oyashio. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Topographic Effect of Izu Ridge on the Distribution of the North Pacific Intermediate Water South of Japan     

Yoshihiko Sekine  Shingo Watanabe  Fukuji Yamada 《Journal of Oceanography》2000,56(4):429-438

The topographic effect of the Izu Ridge on the horizontal distribution of the North Pacific Intermediate Water (NPIW) south of Japan has been studied using observational data obtained by the Seisui-Maru of Mie University (Mie Univ. data) and those compiled by Japan Oceanographic Data Center (JODC data). Both data sets show that water of salinity less than 34.1 psu on potential density () surface of 26.8 is confined to the eastern side of the Izu Ridge, while water of salinity less than 34.2 psu is confined to the southern area over the Izu Ridge at a depth greater than 2000 m and to the southeastern area in the Shikoku Basin. It is also shown by T-S analysis of Mie Univ. data over the Izu Ridge that water of salinity less than 34.2 psu dominates south of 30°N, where the depth of the Izu Ridge is deeper than 2000 m and NPIW can intrude westward over the Izu Ridge. JODC data reveal that relatively large standard deviations of the salinity on surface of 26.7, 26.8 and 26.9 are detected along the mean current path of the Kuroshio and the Kuroshio Extension. Almost all of the standard deviations are less than 0.05 psu in other area with the NPIW, which shows that the time variation in the salinity can be neglected. This observational evidence shows that the topographic effect of the Izu Ridge on the horizontal distribution of the NPIW, which is formed east of 145°E by the mixing of the Kuroshio water and the Oyashio water, is prominent north of 30°N with a depth shallower than 2000 m.  相似文献   

Velocity variation of the Kuroshio during formation of the small meander south of Kyûshû     

Yoshihiko Sekine  Yoshiaki Toba 《Journal of Oceanography》1981,37(2):87-93

Historical GEK data provided by JODC is analyzed to investigate the characteristic variation in velocity of the Kuroshio, with special reference to the formation of small meanders south of Kyûshû. It is found that, during or prior to the period of small meander formation, there is a tendency for an abrupt increase in the current velocity west of Yaku-Shima (Yaku-Island), representing an increase in the main current intensity upstream. Also, there are apparent time lags in the variation in current velocity along the path of the Kuroshio between the upstream and the downstream regions of the small meander area. Namely, it is apparent that the increase in Kuroshio velocity in the Satsunan Strait procedes that offshore of Shikoku during the period of the small meander formation, by the order of one month. These results indicate that a nonlinear effect due to the increase in current velocity is a possible cause of the generation of small meanders.  相似文献   

Wind-driven circulation in the Japan Sea and its influence on the branching of the Tsushima Current     

Yoshihiko Sekine 《Progress in Oceanography》1986,17(3-4)

Seasonal variation in the wind-driven circulation in the Japan Sea is studied with reference to the branching of the Tsushima Current using a two-layer model with simplified bottom and coastal topography. The system is driven by wind stress, an inflow corresponding to the Tsushima Current and by the two outflows corresponding to the Tsugaru and Soya Currents.In the first phase, an annual mean wind stress is imposed and a quasi-stationary state is obtained. In the next phase, a seasonally varying wind stress is imposed. Seasonal variation in the wind stress plays an important role in the branching system of the Tsushima Current. In winter, an intensified western boundary current with a prominent inner circulation is formed as a result of a strong wind stress of winter monsoon with negative wind stress curl. In spring to summer, the western boundary current is weak, but the topographic branch along the Japanese coast is intensified. The weak western boundary current is caused by weak wind stress with positive wind stress curl, which induces cyclonic Sverdrup flow in the Japan Sea and causes its western boundary current to flow in the opposite direction to the prescribed northward boundary inflow current. The topographic branch is strongest in late spring and moves offshore in summer, in agreement with the central branch denoted by Kawabe (1982b). Some of the observational features of the Tsushima Current are successfully simulated.  相似文献   

Observation of oceanic structure around Tosa-Bae southeast of Shikoku     

Yoshihiko Sekine  Haruki Ohwaki  Motoya Nakagawa 《Journal of Oceanography》1994,50(5):543-558

The hydrographic observations in the vicinity of a seamount, the Tosa-Bae, southeast of Shikoku have been carried out two times in summer of 1991 and 1992. The temperature, salinity fields are observed by CTD and velocity fields are measured by ADCP. Results of these observation are presented in this paper. It is shown that salinity maximum water at a depth of 100 m is confined to a southeastern are of the Tosa-Bae, however, salinity minimum water is found in northern side of the Tosa-Bae. This indicates the westward intrusion of less saline water over northern slope. A positive correlation is detected between the estimated Rossby height (fL/N) and the observed height of Taylor Column estimated from the vertical change in the isotherms and isohalines. Almost both heights give smaller value than representative depth of bottom topography of the Tosa-Bae, it is indicated that the topographic effect of the Tosa-Bae is not fully reached to the surface. From the correlations between the vertical difference of geostrophic flow and that of ADCP velocity, ageostrophic flow component is detected.  相似文献   

Thermal structures in the Kuroshio extension measured with a towed thermistor chain     

Yoshihiko Sekine  Fukuji Yamada  Yoshiaki Toba  Eugene C. Lafond 《Journal of Oceanography》1994,50(4):391-401

Two-dimensional temperature data observed by use of a 275 meter towed thermistor chain deployed from an oceanographic research vessel USS MARYSVILLE, which cruised with a speed of 6.2 knots in July 1966 across the Kuroshio Extension in the North Pacific, are investigated. Two-dimensional variations of the distribution of the isotherms along the ship's track are analyzed with special reference to their slope, wavelength and wave height. The results show that the slope and wave height of isotherms have a tendency to increase as the temperature decreases. Even if the contribution of wave heights smaller than 1.5 m is neglected, i.e., contribution of large scale slope with a horizontal scale of 5–30 km is subtracted, this tendency is still detected. In contrast to this, the wavelength evaluated by the crest to crest method has no dependency on the temperature. Power spectrum of the isotherm depth is proportional tok ^–1.87 for 13°C andk ^–2.13 for 27°C, wherek is the wave number. It is shown that the spectra of warmer isotherms are relatively well approximated by –2 power law (Garrett and Munk spectrum) for internal waves rather than the –5/3 power law (Kolmogorov spectrum) for three dimensional isotropic turbulence.  相似文献