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111.
112.
The crust ≈ 10–20 km under the Eifel is composed of amphibolite-facies metasediments and meta-igneous rocks of tonalitic to granodioritic composition; mafic granulites occupy the base of the crust down to a Moho depth between about 29 and 34 km. The meta-granodiorites and meta-tonalites have I-type chemical characteristics and appear to have formed approximately 400 Myr ago by partial melting of a lower crustal source. Amphibolite-facies metamorphism probably followed within the same orogeny. During the Quaternary, many amphibolite-facies rocks were subjected to contact heating in crustal magma chambers and/or during transport to the earth's surface. Contact heating is also recorded in radiogenic isotope compositions of minerals from one xenolith. A genetic link between meta-igneous amphibolites and the deeper crustal mafic granulites can neither be proven nor discounted by the isotope data. If there is a genetic relationship, it requires fractionation of a mafic magma in the lower crust and assimilation of metasediments and separation of a highly evolved melt. 相似文献
113.
114.
A shaking table testing program was undertaken with the main objective of providing basic information for the calibration of analytical models, and procedures for determining seismic response of typical stone masonry temples of the 16–18th centuries stone masonry construction in Mexico. A typical colonial temple was chosen as a prototype. A model at a 1:8 geometric scale was built with the same materials and techniques as the prototype, and was subjected to horizontal and vertical motions of increasing intensities. The maximum applied intensity corresponded to a base shear force of about 58 of the total building weight. Vertical component of the base motion significantly affected the response and increased the damage of the model. Damage patterns were similar to those observed in actual temples. Damping coefficients of the response ranged from 7 for undamaged state, reached about 14 for severe damage. The main features of the measured response were compared with those computed using a nonlinear, finite element model; for the latter, a constitutive law developed for plain concrete was adopted for reproducing cracking and crushing of the irregular stone masonry. Observed damage patterns as well as measured response could be reproduced with reasonable accuracy by the analytical simulation, except for some local vibrations, as those at the top of the bell towers. It can be concluded that the simple constitutive law adopted for the simulation was able to reproduce the experimental response with reasonable level of accuracy. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
115.
Izvestiya, Atmospheric and Oceanic Physics - Long-term average values and anomalies of the duration of the period of positive temperatures and the total water-temperature value have been calculated... 相似文献
116.
Northern marine transportation corridors: Creation and analysis of northern marine traffic routes in Canadian waters 下载免费PDF全文
René Chénier Loretta Abado Olivier Sabourin Laurent Tardif 《Transactions in GIS》2017,21(6):1085-1097
The concept of the Northern Marine Transportation Corridors (NMTC) initiative was developed under the Government of Canada World‐Class Tanker Safety System Initiative (WCTSS). The NMTC is an interdepartmental Arctic initiative within the Department of Fisheries and Oceans Canada (DFO), through the Canadian Coast Guard (CCG) and the Canadian Hydrographic Service (CHS), in collaboration with Transport Canada (TC). The NMTC initiative was developed to strengthen the safety of marine navigation in the Arctic, and to offer an efficient planning guide for present and future Arctic investments. Transportation corridors identified through this initiative will provide the Government of Canada the framework needed to better prioritize and deliver on its programs and services, including: nautical charts and products; aids to navigation; icebreaking services; and marine safety regulations. The corridors were generated and analyzed with a Geographic Information System (GIS) using two main data sources: the Automated Identification System (AIS) and CHS's nautical charts and publications. The geographic extent of the NMTC is defined as the Northern Canada Vessel Traffic Service Zone (NORDREG Zone) and the Mackenzie River. With close to 4 million km2 of water in the Arctic and 162,000 km of coastline, surveying the Arctic to modern standards represents an enormous challenge to CHS. By adopting a corridor‐based approach, CHS and other government programs can prioritize their efforts on 12% of the Canadian Arctic waters. CHS currently has 32% of the NMTC adequately surveyed, with an additional 3% surveyed to modern standards. 相似文献
117.
M. Halimi M. Rezaei Ch. Mohammadi M. Farajzadeh 《Russian Meteorology and Hydrology》2017,42(10):671-676
Relationship between precipitation sum and cloud properties over Fars province in Iran was analyzed for the cases of light (4 mm), moderate (17 mm), and heavy (62 mm) precipitation. The cloud properties (temperature and pressure at the top, cloud optical thickness and cloud water path) were obtained from satellite data of spectoradiometer MODIS (MODO6). The spatial distribution of rainfall was obtained from the 3-hourly data of TRMM (3B42). The multivariate regression model was developed to predict the spatial distribution of rainfall. A strong significant positive association between the spatial distribution of cloud characteristics and heavy precipitation was found, while no clear correlation was revealed between light precipitation and cloud properties. The developed regression model comprised 64, 47, and 24% of spatial variance of heavy, moderate, and light rainfall, respectively. The influence of cloud water path on the spatial distribution of rainfall dominates. 相似文献
118.
Stable isotopes of carbon and nitrogen in suspended matter and sediments from the Godavari estuary 总被引:2,自引:0,他引:2
V. V. S. S. Sarma J. Arya Ch. V. Subbaiah S. A. Naidu L. Gawade P. Praveen Kumar N. P. C. Reddy 《Journal of Oceanography》2012,68(2):307-319
Spatial distribution of the carbon and nitrogen content and their isotopic enrichment in suspended matter and sediments were
measured in the Godavari estuary to identify the sources and transformation mechanism of organic matter. Significant variability
in isotopic distribution was found over the entire length of the Godavari estuary, suggesting multiple sources of organic
matter. The mean isotopic ratios (δ13Csed −25.1 ± 0.9, δ13Csus −24.9 ± 1, δ15Nsed 8.0 ± 2 and δ15Nsus 6.5 ± 0.9‰) and elemental concentrations (Csed 0.45 ± 0.2%, Csus 0.9 ± 0.7%, Nsed 0.07 ± 0.05% and Nsus 0.16 ± 0.1%) support a predominantly terrigenous source. Significant enrichment in the isotopic ratios of δ13C from the upper to lower estuary in both suspended (−27.5 and −24.3‰, respectively) and sedimentary (−26.2 and −24.9‰, respectively)
phases indicates a decrease in the influence of terrigeneous material toward the mouth of the estuary. A significant positive
relationship exists between the δ13C of suspended and sediment, which indicates that these two organic carbon pools are likely coupled in the form of a significant
exchange between the two phases. A positive relationship exists between chlorophyll a and suspended organic matter, which may mean that a significant source of organic carbon is the in situ produced phytoplankton.
But, applying a simple mixing model to our isotopes, data yielded about 46% as the contribution of the terrestrial source
to suspended matter, which may support the excessive heterotrophic activity in the Godavari estuary reported earlier. 相似文献
119.
Reasons for the nonclosure of the heat balance in the atmospheric boundary layers over natural land surfaces are analyzed. Results of measuring the heat-balance components over different land surfaces are used. The Cabauw (Netherlands) data (obtained throughout 1996 over a grass surface with intermittent shrubs and single trees) and the data from the Anchor station in Germany (measured over coniferous forest in 2000–2001) are analyzed. In all, the analysis involves about fifty thousand independent values of the heat-balance components measured in the experiments, which should be indicative of the reliability of the results obtained in the paper. The data have shown that the heat balance is not closed and the imbalance is 50–250 W/m2. The sum of the latent and sensible heat fluxes λE + H = STF is found to be systematically smaller than the difference between the net radiation and the heat flux into the ground R n ? G. It is shown that the main cause of a systematic heat imbalance in the atmospheric boundary layers over inhomogeneous land surfaces is that the methods of surface-flux measurement and estimation are based on the theory that requires the hypothesis of stationarity and horizontal homogeneity. Direct data analysis has shown that the heat imbalance increases with landscape inhomogeneity. In the paper, a parametrization of the heat imbalance is carried out and the coefficient k f (z 0 ef /L ef ) is introduced as a measure of inhomogeneity. For this, data from the experiments FIFE, KUREX, TARTEX, SADE, etc., are also used. Empirical formulas are presented to refine the results of direct measurements and calculations of surface fluxes over natural (inhomogeneous) land surfaces from profile and standard (using bulk parametrizations) data. These formulas can also be used to determine surface fluxes over inhomogeneous underlying land surfaces in order to take into account so-called subgrid-scale effects in constructing prediction models. 相似文献
120.
J. N. Pattan Ch. M. Rao A. A. Migdisov S. Colley N. C. Higgs L. Demidenko 《Marine Georesources & Geotechnology》2001,19(3):155-165
The rare earth element (REE) distribution in nine deep-sea ferromanganese nodules and their associated siliceous sediments from the Central Indian Ocean Basin (CIOB) have been studied to elucidate the REE relationship among them. Total REE concentration varies from 398-928 ppm in the nodules and 137-235 ppm in the associated sediments, suggesting two- to four-fold enrichment in the nodules compared to associated sediments. REE of nodules and their associated sediments show a positive correlation, suggesting REE are supplied from a common source such as seawater. The positive correlation between REE of nodules and sediments from the CIOB is contrary to the competitive scavenging of REE between nodules and sediment in the equatorial Pacific Ocean. REEs in the nodules are carried by Fe, P, and Ti, whereas in the sediment they are carried by P and Mn phases. A similar REE fractionation pattern with middle REE enrichment over heavy and light REE in both the nodules and their associated sediment suggest fractionation is independent of REE abundance and their carrier phases. 相似文献