Modeling households’ decisions on reconstruction of houses damaged by earthquakes––Japanese case study     

H. Sakakibara  H. Murakami  S. Esaki  D. Mori  H. Nakata 《Natural Hazards》2008,44(2):293-303

In this study, households’ decisions on reconstruction of damaged houses were modeled, using questionnaire data in Japan. Characteristics of households’ decisions were investigated using parameter estimation results. The effects of subsidizing policy were evaluated as follows. First, subsidy for rebuilding may be effective for the households whose houses were heavily damaged. Second, there is a possibility that subsidy accelerated rebuilding of houses by the households having children. Third, subsidy for rebuilding may not be effective for elderly people’s households and households in depopulated areas.  相似文献   

Satellite detection of red tide in Ariake Sound, 1998–2001     

Joji Ishizaka  Yasuhisa Kitaura  Yasuharu Touke  Hiroaki Sasaki  Akihiko Tanaka  Hiroshi Murakami  Toshikazu Suzuki  Kazumi Matsuoka  Hideaki Nakata 《Journal of Oceanography》2006,62(1):37-45

High resolution SeaWiFS data was used to detect red tide events that occurred in the Ariake Sound, Japan, a small embayment known as one of the most productive areas in Japan. SeaWiFS chlorophyll data clearly showed that a large red tide event, which damaged seaweed (Nori) cultures, started early in December 2000 in Isahaya Bay, expanded to the whole sound and persisted to the end of February 2001. The monthly average of SeaWiFS data from May 1998 to December 2001 indicated that the chlorophyll peaks appeared twice a year, in early summer and in fall, after the peaks of rain and river discharge. The SeaWiFS data showed that the red tide event during 2000–2001 winter was part of the fall bloom; however, it started later and continued significantly longer than other years. Satellite ocean color data is useful to detect the red tide; however the algorithms require improvement to accurately estimate chlorophyll in highly turbid water and in red tide areas.  相似文献   

Excess CO2 and pHexcess in the Intermediate Water Layer of the Northwestern Pacific     

Andrey Andreev  Makio Honda  Yuichiro Kumamoto  Masashi Kusakabe  Akihiko Murata 《Journal of Oceanography》2001,57(2):177-188

Excess CO₂ and pH_excess showing an increase in dissolved inorganic carbon and a decrease in pH from the beginning of the industrial epoch (middle of the 19th century) until the present time have been calculated in the intermediate water layer of the northwestern Pacific and the Okhotsk Sea. It is concluded that: (1) The Kuril Basin (Okhotsk Sea) and the Bussol' Strait areas are characterized by the greatest concentrations of excess CO₂ at isopycnal surfaces due to the processes of formation and transformation of intermediate water mass. (2) The largest difference in excess CO₂ concentration between the Okhotsk Sea and the western subarctic Pacific (about 8 µmol/kg) is found at the = 27.0. (3) The difference in excess CO₂ between the western subarctic Pacific and subtropical regions is significant only in the upper part of the intermediate water layer ( = 26.7–27.0). (4) About 10% of the excess CO₂ accumulation in the subtropical north Pacific is determined by water exchange with the subarctic Pacific and the Okhotsk Sea.  相似文献   

Distributions and upward fluxes of particulate matter near bottom in the southeastern Bering Sea Shelf     

Masahiro Kajihara  Tsutomu Morinaga  Akihiko Sekine 《Journal of Oceanography》1986,42(5):389-401

Time-series measurements of temperature, salinity, suspended matter and beam attenuation coefficient () were measured at four hour intervals for about two days in June/ July 1982 in the middle shelf region and the coastal region of the southeastern Bering Sea. Current meters were also moored at the same locations.Depth-time distributions of indicated that profiles of suspended matter resulted from a combined process of resuspension of underlying sediments and sinking of suspended particles. Average-values for all measurements for particles revealed that the upward transport of particles due to resuspension formed a boundary layer, with a thickness apparently related to scalar speed. The average-profiles of the particle volume concentration were assumed to result from a balance between the sinking and diffusive flux of particles under a steady state, and the upward fluxes were calculated. Within the boundary layer, values of the upward fluxes of particulate organic matter linearly decreased with the logarithm of distance from the bottom. Fluxes of organic carbon at the upper edge of the boundary layer were 0.375 gC·m^–2·day^–1 in the middle shelf region (18 m above the bottom, bottom depth=78m) and 0.484gC·m^–2·day^–1 in the coastal region (25 m above the bottom, bottom depth=33m), and fluxes of nitrogen in both regions were 0.067 gN·m^–2·day^–1. The flux of organic carbon obtained in the middle shelf region (18 m above the bottom) agreed approximately with the flux (0.416 gC·m^–2·day^–1) calculated by substituting primary production data into the empirical equation of Suess (1980).  相似文献   

Some features of jump in water temperature in aSargassum forest   总被引：1，自引：0，他引：1  

Teruhisa Komatsu  Shin-ichi Murakami  Hideo Kawai 《Journal of Oceanography》1996,52(1):109-124

To clarify the influence of aSargassum forest on water temperature distributions observations were made inside and outside aSargassum forest off the Nagata Shore on the northern Saiki Bay open to the Bungo Channel on the Pacific side of Kyushu, Japan. About sixty thermistor probes were deployed at 0.5 m depth intervals from the bottom to the sea surface at seven stations spaced at 50–80 m distances along two transects: one inside the forest and the other outside. Water temperature was measured at five minutes intervals from 6 to 9 August 1987 with thermistor probes. The spatial standing crop distribution of theSargassum forest along the transects was investigated. A water temperature jump of about 2°C, recorded during the observation, is probably caused by an intrusion of a warm water mass from the central Bungo Channel to Saiki Bay. The water temperature jump under theSargassum forest on the rough bottom with stones occurred one to two hours behind that outside the forest (sandy bed) although the distance between the transects inside and outside the forest was only 50–80 m. It is suggested that theSargassum forest and the rough bottom would prevent intruding warm water from smoothly replacing cold water due to resistance of theSargassum species and the bottom to a current.  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   

Annual and interannual variations of large-scale circulation over the tropics as revealed from OLR data   总被引：1，自引：0，他引：1  

Xie An  Chen Longxun  Takio Murakami 《海洋学报(英文版)》1988,7(2):195-202

In this study, the outgoing longwave radiation (OLR) data of eight years have been used to investigate the annual and interannual variations of large-scale circulation over the tropics. The results of EOF analysis indicate that the first three eigenvectors reflect the essential features in OLR annual variation. However, they contribute little to the interannual change. In comparison, the fourth to the sixth components have very large year-to-year variations. The pronounced anomalies are located over the tropics with east-west dipole pattern. It implies that ENSO events are related closely to the variation of the Walker circulation.  相似文献   

Irrotational,progressive surface gravity waves near the limiting height     

Ken Sasaki  Takashi Murakami 《Journal of Oceanography》1973,29(3):94-105

Numerical solutions of irrotational, progressive surface gravity waves in water of a constant depth are obtained by means of an iterative method. Our results suggest that waves with the surface slope angle greater than/6 may exist. The calculated phase velocity of deep water waves near the wave steepness 0.14 is significantly smaller than the value given by the Stokes' fourth approximation.In order to check our method, we apply it to the problem proposed byDavies (1951), which is hypothetical but similar to the present problem, and for which the exact solution is known. In this case our results show good agreement with the exact solution.  相似文献   

Difference characteristics of sea surface temperature observed by GLI and AMSR aboard ADEOS-II     

Kohtaro Hosoda  Hiroshi Murakami  Akira Shibata  Futoki Sakaida  Hiroshi Kawamura 《Journal of Oceanography》2006,62(3):339-350

This study compares infrared and microwave measurements of sea surface temperature (SST) obtained by a single satellite. The simultaneous observation from the Global Imager (GLI: infrared) and the Advanced Microwave Scanning Radiometer (AMSR: microwave) aboard the Advanced Earth Observing Satellite-II (ADEOS-II) provided an opportunity for the intercomparison. The GLI-and AMSR-derived SSTs from April to October 2003 are analyzed with other ancillary data including surface wind speed and water vapor retrieved by AMSR and SeaWinds on ADEOS-II. We found no measurable bias (defined as GLI minus AMSR), while the standard deviation of difference is less than 1°C. In low water vapor conditions, the GLI SST has a positive bias less than 0.2°C, and in high water vapor conditions, it has a negative (positive) bias during the daytime (nighttime). The low spatial resolution of AMSR is another factor underlying the geographical distribution of the differences. The cloud detection problem in the GLI algorithm also affects the difference. The large differences in high-latitude region during the nighttime might be due to the GLI cloud-detection algorithm. AMSR SST has a negative bias during the daytime with low wind speed (less than 7 ms⁻¹), which might be related to the correction for surface wind effects in the AMSR SST algorithm.  相似文献   

REE Abundance and REE Minerals in Granitic Rocks in the Nanling Range,Jiangxi Province,Southern China,and Generation of the REE‐rich Weathered Crust Deposits     

Shunso Ishihara  Renmin Hua  Mihoko Hoshino  Hiroyasu Murakami 《Resource Geology》2008,58(4):355-372

Studies of Mesozoic granites associated with rare earth element (REE)‐rich weathered crust deposits in southernmost Jiangxi Province indicate that they have high‐K to shoshonite compositions and belong to ilmenite‐series I‐type granites. Of the studied rocks at 59–292 ppm of bulk REE content, the highest are seen in the biotite granites of Dingnan (358, 429 ppm) and mafic biotite granite of the Wuliting Granite (344 ppm) near the Dajishan tungsten mine, both areas where weathered‐crust REE deposits occur. REE‐bearing accessory minerals in these granites are mainly zircon, apatite and allanite, and REE‐fluorocarbonates are common. REE enrichment occurs in the rims of apatite crystals, and in fluorocarbonates that occur along grain boundaries of and cracks in major silicate minerals, and in fluorocarbonates that replaced altered biotite. It is therefore thought that a major part of the REE content of these granites was concentrated during deuteric activity, rather than during magmatic crystallization. The crack‐filling REE‐fluorocarbonates could subsequently have been easily leached out and deposited in weathered crust developed during a long period of exposure.  相似文献