Lead and Antimony Removal from Contaminated Soil by Phytoremediation Combined with an Immobilization Material          下载免费PDF全文

Masahiko Katoh  Kazuki Hashimoto  Takeshi Sato 《洁净——土壤、空气、水》2016,44(12):1717-1724

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A water flow model of the active crater lake at Aso volcano,Japan: fluctuations of magmatic gas and groundwater fluxes from the underlying hydrothermal system     

Akihiko Terada  Takeshi Hashimoto  Tsuneomi Kagiyama 《Bulletin of Volcanology》2012,74(3):641-655

The first crater of Nakadake, peak of Aso volcano, Japan, contains a hot water lake that shows interesting variations in water level and temperature. These variations were discovered by precise, continuous observations of the lake independent of precipitation. We developed a numerical model of a hot crater lake and compared with observational data for the period from July 2006 to January 2009. The numerical model revealed seasonal changes in mass flux (75–132 kg/s) and enthalpy (1,840–3,030 kJ/kg) for the fluid supplied to the lake. The relation between the enthalpy and mass flux indicates that the bottom input fluid is a mixture of high- and low-temperature fluids. Assuming a mixture of high-temperature steam at 800°C and liquid water at 100°C, we evaluated the liquid and steam fluxes. The liquid water flux shows a seasonal increase lagging behind the rainy season by 2 months, suggesting that the liquid water is predominantly groundwater. The fluctuation pattern in the flux of the high-temperature steam shows a relation with the amplitude of volcanic tremor, suggesting that heating of the hydrothermal system drives the tremor. Consequently, precise observations of a hot crater lake represent a potential method of monitoring volcanic hydrothermal systems in the shallow parts of the volcanoes.  相似文献   

Observations of turbulence under weakly and highly stratified conditions in the Ariake Sea     

Eisuke Tsutsumi  Takeshi Matsuno 《Journal of Oceanography》2012,68(3):369-386

Observations of turbulence, stratification, and mean current were made using a microstructure profiler and an acoustic Doppler current profiler (ADCP) during four cruises at a central location in the Ariake Sea, under weakly and strongly stratified conditions. Continuous measurements of the dissipation rate of turbulent kinetic energy (TKE), ε, were made. These revealed that frictional bed turbulence with quarterdiurnal variation in the bottom boundary layer (BBL) was one of the most energetic sources of vertical mixing in the sea. Thickness of the BBL was strongly confined by the stable stratification. We investigate a relationship between the BBL height h and the Ozmidov scale. We present a systematic argument that describes the vertical structure and characteristic scales of velocity and turbulence inside the frictional BBL, where the stratification persisted. Considerable deviation of observed vertical shear from the law of the wall indicated a modification of turbulent scales by the stratification. Shear stress calculated from the velocity data using vertical integration of the equation of motion was found to decrease approximately linearly with height. The TKE production rate P, estimated using the shear stress, was highly correlated with the dissipation rate. The buoyancy contribution to TKE balance in the BBL was quantified in terms of the flux Richardson number R _f as R _f?=?0.12.  相似文献   

Interaction between waves and an array of floating porous circular cylinders   总被引：1，自引：0，他引：1  

赵芬芳  鲍伟光  黄六一  梁振林  万荣 《中国海洋工程》2012,26(3):397-412

The present study theoretically as well as experimentally investigates the interaction between waves and an array of porous circular cylinders with or without an inner porous plate based on the linear wave theory.To design more effective floating breakwaters,the transmission rate of waves propagating through the array is evaluated.Each cylinder in the array is partly made of porous materials.Specifically,it possesses a porous sidewall and an impermeable bottom.In addition,an inner porous plate is horizontally fixed inside the cylinders.It dissipates the wave more effectively and eliminates the sloshing phenomenon.The approach suggested by Kagemoto and Yue(1986) is adopted to solve the multiple-scatter problem,while a hierarchical interaction theory is adopted to deal with hydrodynamic interactions among a great number of bodies,which efficiently saves computation time.Meanwhile,a series of model tests with an array of porous cylinders is performed in a wave basin to validate the theoretical work and the calculated results.The draft of the cylinders,the location of the inner porous plate,and the spacing between adjacent cylinders are also adjusted to investigate their effects on wave dissipation.  相似文献   

Horizontal structure of planetary-scale waves at the cloud top of Venus deduced from Galileo SSI images with an improved cloud-tracking technique     

Toru Kouyama  Takeshi Imamura  Masato Nakamura  Takehiko Satoh  Yoshihumi Futaana 《Planetary and Space Science》2012,60(1):207-216

An improved cloud tracking method for deriving wind velocities from successive planetary images was developed. The new method incorporates into the traditional cross-correlation method an algorithm that corrects for erroneous cloud motion vectors by re-determining the most plausible correlation peak among all of the local maxima on the correlation surface by comparing each vector with its neighboring vectors. The newly developed method was applied to the Venusian violet images obtained by the Solid State Imaging system (SSI) onboard the Galileo spacecraft during its Venus flyby. Although the results may be biased by the choice of spatial scale of atmospheric features, the cloud tracking is the most practical mean of estimating the wind velocities with extensive spatial and temporal coverage. The two-dimensional distribution of the horizontal wind vector field over 5 days was obtained. It was found from these wind maps that the solar-fixed component in 1990 was similar to that in 1982 obtained by the Pioneer Venus orbiter. The deviation of the instantaneous zonal wind field from the solar-fixed component shows a distinct wavenumber-1 structure in the equatorial region. On the assumption that this structure is a manifestation of an equatorial Kelvin wave, the phase relationship between the zonal wind and the cloud brightness suggests a short photochemical lifetime of the violet absorber. The momentum deposition by this Kelvin wave, which is subject to radiative damping, would induce a westward mean-wind acceleration of ～0.3 m s^?1 per Earth day.  相似文献   

Uptake and biological effects of synthetic glucocorticoids in common carp (Cyprinus carpio)     

Kei Nakayama  Yoshiyuki Inoue  Naomi Ikeda  Naoki Hashizume  Hidekazu Murakami  Takeshi Ishibashi  Hirofumi Ikeda  Tomohiko Isobe  Shin-Ichi Kitamura  Go Suzuki 《Marine pollution bulletin》2014

Uptake and biological effects of synthetic glucocorticoids (GCs) were analyzed using common carp (Cyprinus carpio). Fish were exposed to clobetasol propionate (CP) or clobetasone butyrate (CB) individually or in mixture at 1 μg L⁻¹ for 21 days. Bioconcentration factor (BCF) of CB was calculated as 100, and BCF of CP was less than 16. No effects were found in fish erythrocyte and leukocyte numbers and serum glucose levels after exposure to the selected GCs. On the other hand, serum concentrations of free amino acids significantly increased in GC-exposed groups. Thus, exposures to synthetic GCs at relatively low concentrations seemed to cause enhancement of protein degradation and subsequent increase of serum free amino acids without a corresponding increase in serum glucose levels, an effect which might be related to partial induction of gluconeogenesis by GC.  相似文献   

实时 Ｇ Ｐ Ｓ可降水量资料的变分同化个例研究   总被引：2，自引：1，他引：1  

顾莹  日下博幸  束炯  岩淵哲也  田中创  守屋岳 《气象科学》2010,30(2):172-178

用实时GPS可降水量(Precipitable Water, PW)资料GPSPW,针对2007年7月2-3日发生在日本九州南部地区的一次梅雨锋降水过程,设计控制试验和4个同化试验,利用WRF和WRF-Var模式进行三维变分同化研究,并用ETS评分客观评价各方案的预报效果.结果表明:实时GPSPW同化能有效地改进模式初始时刻水汽场以及预报时间内(0～6 h)的PW.背景误差水平尺度调节系数的大小对水汽场的调整范围和PW的改进程度有一定影响.GPSPW的实时性能提高降水预报业务的实时性.  相似文献   

Interannual variability of the Guinea Dome and its possible link with the Atlantic Meridional Mode   总被引：1，自引：0，他引：1  

Takeshi Doi  Tomoki Tozuka  Toshio Yamagata 《Climate Dynamics》2009,33(7-8):985-998

Using a high-resolution ocean general circulation model forced by NCEP/NCAR reanalysis data, the interannual variability of the Guinea Dome is studied from a new viewpoint of its possible link with the Atlantic Meridional Mode (AMM), which is related to the meridional migration of the Intertropical Convergence Zone (ITCZ). The dome develops off Dakar seasonally from late spring to late fall owing to the wind-induced Ekman upwelling; its seasonal evolution is associated with the northward migration of the ITCZ. When the ITCZ is located anomalously northward (southward) from late spring to early summer, as a result of the wind-evaporation-sea surface temperature (SST) positive feedback with positive (negative) SST anomaly over the Northern Hemisphere, the dome becomes unusually strong (weak) in fall as a result of stronger (weaker) Ekman upwelling. This may contribute to the decay of the AMM. Thus, the coupled nature between the AMM and the Guinea Dome could be important in understanding, modeling, and predicting the tropical Atlantic variability.  相似文献   

Aerodynamic Scaling for Estimating the Mean Height of Dense Canopies   总被引：1，自引：1，他引：0  

Taro Nakai  Akihiro Sumida  Kazuho Matsumoto  Ken’ichi Daikoku  Shin’ichi Iida  Hotaek Park  Mie Miyahara  Yuji Kodama  Alexander V. Kononov  Trofim C. Maximov  Hironori Yabuki  Toshihiko Hara  Takeshi Ohta 《Boundary-Layer Meteorology》2008,128(3):423-443

We used an aerodynamic method to objectively determine a representative canopy height, using standard meteorological measurements. The canopy height may change if the tree height is used to represent the actual canopy, but little work to date has focused on creating a standard for determining the representative canopy height. Here we propose the ‘aerodynamic canopy height’ h _a as the most effective means of resolving the representative canopy height for all forests. We determined h _a by simple linear regression between zero-plane displacement d and roughness length z ₀, without the need for stand inventory data. The applicability of h _a was confirmed in five different forests, including a forest with a complex canopy structure. Comparison with stand inventory data showed that h _a was almost equivalent to the representative height of trees composing the crown surface if the forest had a simple structure, or to the representative height of taller trees composing the upper canopy in forests with a complex canopy structure. The linear relationship between d and z ₀ was explained by assuming that the logarithmic wind profile above the canopy and the exponential wind profile within the canopy were continuous and smooth at canopy height. This was supported by observations, which showed that h _a was essentially the same as the height defined by the inflection point of the vertical profile of wind speed. The applicability of h _a was also verified using data from several previous studies.  相似文献   

Impacts of climate change on growth, migration and recruitment success of Japanese sardine (Sardinops melanostictus) in the western North Pacific     

Takeshi Okunishi  Shin-ichi Ito  Taketo Hashioka  Takashi T. Sakamoto  Naoki Yoshie  Hiroshi Sumata  Yumiko Yara  Naosuke Okada  Yasuhiro Yamanaka 《Climatic change》2012,115(3-4):485-503

We developed a multi-trophic level ecosystem model by coupling physical, biogeochemical-plankton and fish models. An oceanic general circulation model was coupled with a lower trophic level ecosystem model and a Japanese sardine migration model, and applied to the western North Pacific. To investigate the impact of global warming on the pelagic fish ecosystem, such as Japanese sardine, we conducted numerical experiments of growth and migration of Japanese sardine using physical fields for the present day and future with a global warming scenario simulated by a high-resolution climate model. The model results demonstrated possible impacts of global warming on the growth and migration pattern of Japanese sardine. The growths of fish in the current main spawning region under the global warming scenario were significantly slower than those under the present climate scenario. Fish in this region will be at disadvantage for their recruitment under the global warming condition. Prey conditions in the spawning region were projected not to markedly change under global warming condition while water temperature increased. As a result sardine spawning ground was projected to shift towards more north areas. During the feeding migration period in summer, geographical distribution of juveniles fish was projected to shift northwards by one to two degrees latitude under the global warming condition following the change in the distribution of optimal temperature region for feeding. However, this northwards shift of the optimal temperature for feeding was minimized adjacent to the western North Pacific by the cooler water supply by the intensification of the Oyashio.  相似文献