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361.
Akihiro Iwase Kazuhiko Sakai Atsushi Suzuki Robert van Woesik 《Estuarine, Coastal and Shelf Science》2008,77(4):672-678
We tested the hypothesis that foliose plates of Echinopora lamellosa (Esper, 1795) adjust their primary growth direction (or slope from the horizontal) when irradiance (light) is limiting. This hypothesis was tested at a coral-reef locality that is shaded daily by steep adjacent hills, restricting direct light to only a few hours each day (Iwayama Bay, Palau). The angle at which colonies received maximum light was measured using acetate film, and was compared with modeled estimates (using a simple global-light model). We show strong relationships between light and primary-colony gradients; with the foliose plates acting as parabolic antennae, predictably adjusting their primary gradients to optimize light capture. 相似文献
362.
Delphis F. Levia Kazuki Nanko Hiromasa Amasaki Thomas W. Giambelluca Norifumi Hotta Shin'ichi Iida Ryan G. Mudd Michael A. Nullet Naoki Sakai Yoshinori Shinohara Xinchao Sun Masakazu Suzuki Nobuaki Tanaka Chatchai Tantasirin Kozo Yamada 《水文研究》2019,33(12):1698-1708
Although we know that rainfall interception (the rain caught, stored, and evaporated from aboveground vegetative surfaces and ground litter) is affected by rain and throughfall drop size, what was unknown until now is the relative proportion of each throughfall type (free throughfall, splash throughfall, canopy drip) beneath coniferous and broadleaved trees. Based on a multinational data set of >120 million throughfall drops, we found that the type, number, and volume of throughfall drops are different between coniferous and broadleaved tree species, leaf states, and timing within rain events. Compared with leafed broadleaved trees, conifers had a lower percentage of canopy drip (51% vs. 69% with respect to total throughfall volume) and slightly smaller diameter splash throughfall and canopy drip. Canopy drip from leafless broadleaved trees consisted of fewer and smaller diameter drops (D50_DR, 50th cumulative drop volume percentile for canopy drip, of 2.24 mm) than leafed broadleaved trees (D50_DR of 4.32 mm). Canopy drip was much larger in diameter under woody drip points (D50_DR of 5.92 mm) than leafed broadleaved trees. Based on throughfall volume, the percentage of canopy drip was significantly different between conifers, leafed broadleaved trees, leafless broadleaved trees, and woody surface drip points (p ranged from <0.001 to 0.005). These findings are partly attributable to differences in canopy structure and plant surface characteristics between plant functional types and canopy state (leaf, leafless), among other factors. Hence, our results demonstrating the importance of drop‐size‐dependent partitioning between coniferous and broadleaved tree species could be useful to those requiring more detailed information on throughfall fluxes to the forest floor. 相似文献
363.
Yasuhiro Ishizaki Hideo Shiogama Seita Emori Tokuta Yokohata Toru Nozawa Tomoo Ogura Manabu Abe Masakazu Yoshimori Kiyoshi Takahashi 《Climatic change》2012,112(2):535-546
To preserve consistency among developed emission scenarios, the scenarios used in climate modeling, and the climate scenarios
available for impact research, the pattern scaling technique is useful technique. The basic assumption of pattern scaling
is that the spatial response pattern per 1 K increase in the global mean surface air temperature (SAT) (scaling pattern) is
the same among emission scenarios, but this assumption requires further validation. We therefore investigated the dependence
of the scaling pattern of the annual mean SAT on GHGs emission scenarios of representative concentration pathways (RCP) and
the causes of that dependence using the Model for Interdisciplinary research on Climate 5 developed by Japanese research community.
In particular, we focused on the relationships of the dependency with effects of aerosols and Atlantic meridional overturning
circulation. We found significant dependencies of the scaling pattern on emission scenarios at middle and high latitudes of
the Northern Hemisphere, with differences of >15 % over parts of East Asia, North America, and Europe. Impact researchers
should take into account those dependencies that seriously affect their research. The mid-latitude dependence is caused by
differences in sulfate aerosol emissions per 1 K increase in the global mean SAT, and the high-latitude dependence is mainly
caused by nonlinear responses of sea ice and ocean heat transport to global warming. Long-term trends in land-use and land-cover
changes did not significantly affect the scaling pattern of annual mean SAT, but they might have an effect at different timescales. 相似文献
364.
O, Hf and Os isotope data are presented for lavas from the highly depleted Tonga–Kermadec arc. O isotope values overlap with those of MORB limiting the amount of interaction with the arc crust. δ18O does not increase northwards as would be expected from the ~ 4 fold increase in subduction rate if slab-derived fluids had high 18O/16O ratios. Thus, the overall northward decrease in HFSE concentrations likely reflects depletion due to prior melt extraction, not increasing extents of melting. Hf isotopes are strongly negatively correlated with Be isotopes consistent with mixing of subducted pelagic sediment into the mantle wedge and do not require Hf to be fluid mobile. With the exception of a boninite from the north Tongan trench, the northern Tonga lavas do not overlap the Hf isotope composition of either the Samoan plume or the subducting Louisville volcaniclastic sediments. Thus, the Pb isotope signatures in these lavas must have been added by fluids and sediment melts derived from the Louisville volcaniclastics with minimal mobilisation of Hf. This suggests conservative behaviour for this element due to the formation of residual zircon during partial melting of the subducted sediments. 187Os/188Os ranges from 0.1275 to 0.4731 and the higher Os isotope ratios reflect the sensitivity of this system to even minor interaction with altered arc crust. Conversely, the lowest Os ratios are subchondritic and indicate that transfer of radiogenic Os from the slab is not all pervasive and provide an important constraint on the composition of the mantle wedge. Remarkably, the least radiogenic sample is a dacite demonstrating that evolved magmas can develop by fractionation from mantle-derived magmas with minimal interaction with the arc crust. 相似文献
365.
A review of probabilistic and deterministic liquefaction evaluation procedures reveals that there is a need for a comprehensive approach that accounts for different sources of uncertainty in liquefaction evaluations. For the same set of input parameters, different models provide different factors of safety and/or probabilities of liquefaction. To account for the different uncertainties, including both the model and measurement uncertainties, reliability analysis is necessary. This paper presents a review and comparative study of such reliability approaches that can be used to obtain the probability of liquefaction and the corresponding factor of safety. Using a simplified deterministic Seed method, this reliability analysis has been performed. The probability of liquefaction along with the corresponding factor of safety have been determined based on a first order second moment (FOSM) method, an advanced FOSM (Hasofer–Lind) reliability method, a point estimation method (PEM) and a Monte Carlo simulation (MCS) method. A combined method that uses both FOSM and PEM is presented and found to be simple and reliable for liquefaction analysis. Based on the FOSM reliability approach, the minimum safety factor value to be adopted for soil liquefaction analysis (depending on the variability of soil resistance, shear stress parameters and acceptable risk) has been studied and a new design safety factor based on a reliability approach is proposed. 相似文献
366.
Masakazu Chijimatsu Lenart Börgesson Tomoo Fujita Petri Jussila Son Nguyen Jonny Rutqvist Lanru Jing 《Environmental Geology》2009,57(6):1255-1261
In the international DECOVALEX-THMC project, five research teams study the influence of thermal-hydro-mechanical (THM) coupling
on the safety of a hypothetical geological repository for spent fuel. In order to improve the analyses, the teams calibrated
their bentonite models with results from laboratory experiments, including swelling pressure tests, water uptake tests, thermally
gradient tests, and the CEA mock-up THM experiment. This paper describes the mathematical models used by the teams, and compares
the results of their calibrations with the experimental data. 相似文献
367.
Suzuki G Kai S Yamashita H Suzuki K Iehisa Y Hayashibara T 《Marine pollution bulletin》2011,62(12):2803-2812
The initial factors that cause a decline in the survival of in situ settled corals remain poorly understood. In this study, we demonstrated through field experiments that the design of artificial grid plates may influence the initial survival of Acropora corals, with narrower grids being the most effective. In fact, grid plates with a 2.5-cm mesh presented the highest recorded survival rate (14%) at 6 months after settlement (representing approximately 50 corals per 0.25 m2 of plate). This is the first study where such high survival rates, matching those of cultures under aquarium conditions, were obtained in the field without using additional protective measures, such as guard nets against fish grazing after seeding. Therefore, our results provide a foundation for establishing new and effective coral restoration techniques for larval seeding, in parallel to clarifying the details of the early life stages of reef-building corals. 相似文献
368.
Masakazu?NiwaEmail author Hideki?Kurosawa Koji?Shimada Tsuneari?Ishimaru Hideki?Kosaka 《Pure and Applied Geophysics》2011,168(5):887-900
Previous studies have reported that high concentrations of H2 gas are released from active fault zones. Experimental studies suggest that the H2 gas is derived from the reaction of water with free radicals formed when silicate minerals are fractured at hypocenter depths
during fault activities. However, the pathways for migration of deep-seated fluids to surface are still unknown. In this study
we performed quick, multipoint H2 gas measurements across a fault zone using a portable gas monitor and a hand drill. The fault zone studied includes a smectite-rich
fault core dividing two clearly distinguishable damage zones: granite cataclasite and welded tuff fault breccia. The measurements
show that H2 gas emissions collected in 2–3 h sampling periods from start of measurement range from 320.3 to 446.2 ppm/min in the granite
cataclasite and 60.5 to 137.8 ppm/min in the welded tuff fault breccias. Negligible quantities of H2 gas could be collected from the fault core. Particle size distribution analyses of fault rocks indicate that the granite
cataclasite tends to be rich in particles that are finer, i.e., less cohesive and easy to disaggregate, which leads to the
inference that the granite cataclasite has high permeability. Based on the H2 gas measurements and the particle size distribution analyses, the H2 gas is considered to have migrated in permeable damage zones mostly by advection with groundwater. Multipoint H2 gas measurement will be effective in qualitative delineation of variations in permeability of regional structures. 相似文献
369.
Wave energy flow in shallow ground depth is calculated based on main shock records obtained at 30 vertical array sites throughout Japan during nine recent strong earthquakes (MJ=6.4–8.0) by assuming vertical propagation of SH waves. It is generally found that upward energy tends to decrease considerably as it goes up from the base (about 100 m deep) to the ground surface. Large energy is reflected at layer boundaries with clear impedance contrast and returns to deeper ground, so that only less than 10–30% of the upward energy at the base level arrives at the ground surface in most sites. Energy dissipation calculated from the upward and downward energies tends to increase with the increase of damping ratio of the ground back-calculated from the seismic records. It is also found that the upward energy at the base may roughly be estimated for engineering purposes using spherical energy radiation of the body wave despite strong effects of fault rupture/path mechanisms. 相似文献
370.
Masakazu TAGUCHI 《大气科学进展》2020,37(3):250-258
This study reports verification results of hindcast data of four systems in the subseasonal-to-seasonal(S2S)prediction project for major stratospheric sudden warmings(MSSWs)in northern winter from 1998/99 to 2012/13.This report deals with average features across all MSSWs,and possible differences between two MSSW types(vortex displacement and split types).Results for the average features show that stratospheric forecast verifications,when further averaged among the four systems,are judged to be successful for lead times around 10 d or shorter.All systems are skillful for lead times around 5 d,whereas the results vary among the systems for longer lead times.A comparison between the MSSW types overall suggests larger forecast errors or lower skill for MSSWs of the vortex split type,although the differences do not have strong statistical significance for almost all cases.This limitation is likely to at least partly reflect the small sample size of the MSSWs available. 相似文献