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21.
A multilayer one-dimensional canopy model was developed to analyze the relationship between urban warming and the increase in energy consumption in a big city. The canopy model, which consists of one-dimensional diffusion equations with a drag force, has three major parameters: building width, distance between buildings, and vertical floor density distribution, which is the distribution of a ratio of the number of the buildings that are taller than some level to all the buildings in the area under consideration. In addition, a simplified radiative process in the canopy is introduced. Both the drag force of the buildings and the radiative process depend on the floor density distribution. The thermal characteristics of an urban canopy including the effects of anthropogenic heat are very complicated. Therefore, the focus of this research is mainly on the basic performance of an urban canopy without anthropogenic heat. First, the basic thermal characteristics of the urban canopy alone were investigated. The canopy model was then connected with a three-dimensional mesoscale meteorological model, and on-line calculations were performed for 10 and 11 August, 2002 in Tokyo, Japan. The temperature near the ground surface at the bottom of the canopy was considerably improved by the calculation with the canopy model. However, a small difference remained between the calculation and the observation for minimum temperature. Deceleration of the wind was well reproduced for the velocity at the top of the building by the calculation with the canopy model, in which the floor density distribution was considered.  相似文献   
22.
Giant Megamullion in the Parece Vela Backarc Basin   总被引:1,自引:0,他引:1  
We present results of high-resolution bathymetric studies of the extinct intermediate-spreading Parece Vela Basin in the northwestern Pacific, where we have identified an extremely large mullion structure, here termed a giant megamullion. We find that the giant megamullion is nearly an order of magnitude larger than the similar structures in the slow-spreading Mid-Atlantic Ridge (`megamullions'). The giant megamullion has slightly elevated mantle Bouguer anomaly, and yields serpentinized peridotites and gabbros, suggesting that they are exposing oceanic crust and upper mantle. An off-axis rugged `chaotic terrain' was also identified in the Parece Vela Basin. The terrain consists of isolated and elevated blocks capped by corrugated axis-normal lineations, and associated deeps. We thus interpret it as analogues to the Mid-Atlantic Ridge megamullions. We propose that amagmatic tectonics producing the giant megamullion and the chaotic terrain occupied a significant part in crustal construction in the Parece Vela Basin evolution.  相似文献   
23.
In order to reconstruct the architectural evolution of a fault zone with heterogeneous structures, we studied the Atera Fault in Central Japan, and described the detailed mesoscopic and microscopic features of the zone. The fault zone studied consists of a 1.2‐m wide fault core of fault breccia mixed with fragments derived from welded tuff, granite, and mafic volcanic rocks. The 1.2‐m wide fault core is bordered by a western damage zone characterized by a welded tuff fault breccia and an eastern damage zone characterized by a granite cataclasite. A secondary fault core, a 30‐cm wide granite‐derived fault gouge, cross‐cuts the granite cataclasite. Although welded tuff fault breccia and granite cataclasite are also pervasively fractured and fragmented, the fault cores are significantly affected by fragment size reduction due to intense abrasive wear and comminution. The 1.2‐m wide fault core includes fragments and a sharp dark layer composed of mafic volcanic rocks, which can be correlated with neighboring 1.6 Ma volcanic rocks. This observation places a younger constraint on the age of the fault core formation. Carbonate coating on basalt fragments in the 1.2‐m wide fault core has also been fractured indicating the repetition of intense fragmentation. Bifurcated, black and gray veins near the 1.2‐m wide fault core are likely injection veins, formed by the rapid injection of fine material within fault zones during seismic events. The granite‐derived fault gouge, characterized by hard granite fragments without intense brecciation and microfracturing, in a kaolinite‐rich clay matrix, is interpreted as the most recent slip zone within the exposed fault zone. A preview of published geological and hydrological studies of several fault zones shows that clay‐rich fault cores can exhibit much lower permeability than the adjacent damage zones represented in this present case by the welded tuff fault breccia and granite cataclasite.  相似文献   
24.
Multiple ΛCDM cosmology is studied in a way that is formally a classical analog of the Casimir effect. Such cosmology corresponds to a time-dependent dark fluid model or, alternatively, to its scalar field presentation, and it motivated by the string landscape picture. The future evolution of the several dark energy models constructed within the scheme is carefully investigated. It turns out to be almost always possible to choose the parameters in the models so that they match the most recent and accurate astronomical values. To this end, several universes are presented which mimic (multiple) ΛCDM cosmology but exhibit Little Rip, asymptotically de Sitter, or Type I, II, III, and IV finite-time singularity behavior in the far future, with disintegration of all bound objects in the cases of Big Rip, Little Rip and Pseudo-Rip cosmologies.  相似文献   
25.
We examined the effect of the 11-year solar cycle and quasi-biennial oscillation (QBO) on the ~27-day solar rotational period detected in tropical convective cloud activity. We analyzed the data of outgoing longwave radiation (OLR) for AD1979–2004, dividing into four different cases by the combination of high and low solar activities in terms of the 11-year variation, and easterly and westerly stratospheric winds associated with QBO. As a result, ~27-day variation has been most significantly detected in high solar activity period around the Indo-Pacific Warm Pool. Based on correlation analysis, we find that solar rotation signal can explain 10–20% of OLR variability around the tropical warm pool region during the high solar activity period. The spatial distribution has been, however, apparently different according to the phases of QBO. It is suggested that the 11-year solar cycle and stratospheric QBO have a possibility to cause large-scale oceanic dipole phenomena.  相似文献   
26.
In this study, the sensitivities of surface air temperatures to anthropogenic heat (AH) were investigated in downtowns of the two Japanese major cities, Tokyo and Osaka. First, meteorological measurements were made with the simultaneous monitoring of electricity demand in a contrastive couple of a downtown commercial area (C-area) and a residential area (R-area) within each city in summer 2007. From the measurements, the areal-mean surface air temperatures were obtained as \( {\overline{T}}_{\mathrm{C}} \) and \( {\overline{T}}_{\mathrm{R}} \) for each of the C-area and R-area, respectively. Using the actual electricity demand and the estimated motor fuels consumption, their areal total was evaluated as the energy-consumption-basis AH. The estimated C-areas' AH indicated greater values up to 220 W/m2 on weekdays and remarkable decrease about by half on weekends, whereas that in the R-areas showed less values of 10–20 W/m2 stably. Then, \( {\overline{T}}_{\mathrm{C}}-{\overline{T}}_{\mathrm{R}} \) on calm and fine days were found to be systematically decreased from weekdays to weekends in both cities roughly indicating a proportional relationship with the reductions in the C-areas' AH on weekends. The result suggested a common afternoon sensitivity for both C-areas of around 1.0°C/100 W/m2, which indicated an intensity of the AH impact on surface air temperature there. Next, to simulate the observed AH impact, the authors' CM-BEM (a multilayer urban canopy model coupled with a building energy model) was newly implemented in the mesoscale Weather Research and Forecasting (WMF) model. This new system, WRF-CM-BEM, was applied to Tokyo and almost reasonably validated from the aspects of the reproducibility of urban surface air temperature and electricity demand in the observation areas. The simulations also suggested that WRF-CM-BEM underestimated the observed air temperature sensitivity to AH in the Tokyo C-area roughly by half but still in the same order of magnitude.  相似文献   
27.
Direct deposition measurements ofatmospheric insoluble particles over the sub-ArcticNorth Pacific indicate that the number of particles(6.4 ± 3.8) × 104 cm-2 per rain eventwas fairly constant compared with the large variationof the precipitation rate, which ranged from 0.16 to18 mm per event for 43 rain days during the period ofMarch–September (total 109 days) 1996. Thissuggests that insoluble particles larger than 0.4 min area equivalent diameter are primarilyremoved at the margin of the rainfall area by wetscavenging processes below clouds in the marineatmosphere in sub-Arctic regions. The frequency ofrain events controls the fate of the troposphericaerosols larger than sub-micrometer in diameter. Reflecting the seasonal long-range transport of Asiandust, mineral particles were dominant as insolubleparticles in the spring rains, but carbonaceousparticles were dominant in the summer rains. Theatmospheric deposition of insoluble particles could besignificant as a source of sediment particles over thesub-Arctic North Pacific.  相似文献   
28.
In recent years, antibiotics have been used widely in intensive shrimp culture and this may lead to their contamination of the environment. Surveys on residues of trimethoprim (TMP), sulfamethoxazole (SMX), norfloxacin (NFXC) and oxolinic acid (OXLA) in water and mud in shrimp ponds in mangrove areas were conducted in the north as well as in south of Viet Nam in July and August, 2002. The results show that these antibiotics are found in all samples in both shrimp ponds and surrounding canals. The highest concentrations of TMP, SMX, NFXC and OXLA are 1.04, 2.39, 6.06, and 2.50 ppm in water samples; and 734.61, 820.49, 2615.96, 426.31 ppm (based on wet mud weight), respectively. The comparison of antibiotics residues between study sites and types of shrimp ponds will be discussed in this paper. The results also suggest that antibiotics residues may cause harmful effect on ecosystems in the study sites.  相似文献   
29.
Abstract A water injection experiment was carried out by the scientific drilling program named the 'Nojima Fault Zone Probe' during the two periods 9–13 February and 16–25 March 1997. The pumping pressure at the surface was approximately 4 MPa. The total amount of injected water was 258 m3. The injection was made between depths of 1480 m and 1670 m in the Disaster Prevention Research Institute, Kyoto University (DPRI) 1800 m borehole drilled into the Nojima Fault zone. A seismic observation network was deployed to monitor seismic activity related to the water injections. Seismicity suddenly increased in the region not far from the injection hole 4 or 5 days after the beginning of each water injection. These earthquakes were likely to be induced by the water injections. Most of the earthquakes had magnitudes ranging from −2 to +1. Numerous earthquakes occurred during the first injection, but only one could be reliably located and it was approximately 2 km north of the injection site. Between the two injection periods, earthquakes concentrated in the region approximately 1 km northwest of the injection site. During and after the second injection experiment, earthquakes were located approximately 1.5 km west of the injection site. Those earthquakes were located approximately 3 km or 4 km from the injection point and between 2 km and 4 km in depth. Values of intrinsic permeability of 10−14–10−15 m2 were estimated from the time lapse of the induced seismic activity. The coefficient of friction in the area where the induced earthquakes occurred was estimated to be less than 0.3.  相似文献   
30.
Mapping of the oxygen and carbon isotopic composition of hydrothermally altered wall rocks was conducted during blind ore prospecting for Pb---Zn skarn deposits in the Kamioka mining district, central Japan. The wall rocks consist of heterogeneous rock units. Oxygen and carbon isotope ratios were determined for 35 limestones and 33 silicate rocks from the area around the Mozumi deposit (3 km × 3 km) in the Kamioka mining district. The results (δ18Ospsmow of − 1.1 to + 17.3% and δ13Csppdb of − 5.0 to +4.8% for limestones, and δ18Ospsmow of −0.8 to + 12.5% for silicate rocks) show isotope zonations of the wall rocks, with lighter isotopic compositions toward the center of mineralization. The isotope zonations likely formed by interaction of thermal waters with the wall rocks during skarn mineralization. The isotopically light zone indicates a higher paleotemperature or higher water-to-rock ratios, and occurs in the footwall of the 7Gohi fault. This structure is spatially related to the distribution of orebodies, indicating that the fault was the main conduit of the ore-forming fluids. The oxygen and carbon isotopic compositions of limestones vary regularly across limestone bodies hosted by the silicate wall rocks, suggesting that the thermal waters were pervasive throughout the wall rocks at the time of mineralization.An isotopically light zone was also found in the southeastern corner of the study area, where significant mineralization had yet to be identified. This suggested an extension of the extinct hydrothermal system to this area, and the possibility of hidden orebodies underneath. Recent drilling in this area has intercepted a zone 45 m thick with a grade of 13.4% Zn, 0.03% Pb and 8 g per metric ton at about 380 m depth.  相似文献   
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