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931.
V. Loizeau A. Abarnou P. Cugier A. Jaouen-Madoulet A. -M. Le Guellec A. Menesguen 《Marine pollution bulletin》2001,43(7-12):242-255
A bioaccumulation model was developed to simulate the PCB contamination in the sea bass food web from the Seine Estuary. The model relies upon a contaminant mass balance budget for each biological species. Biological processes determine the extent of bioaccumulation: respiration and feeding rates control the uptake of contaminants whereas excretion, spawning, and growth act on the chemicals removal. A step-by-step modelling approach was followed. A first version was a steady-state model validated for the bioaccumulation processes. In the second version seasonal variation was taken into account, and finally in the third version, the model was coupled with a population dynamics model to describe PCB contamination in each age class. 相似文献
932.
933.
Infrasonic Signal Detection and Source Location at the Prototype International Data Centre 总被引:1,自引:0,他引:1
D. J. Brown C. N. Katz R. Le Bras M. P. Flanagan J. Wang A. K. Gault 《Pure and Applied Geophysics》2002,159(5):1081-1125
—?This paper describes an automatic and interactive data processing system designed to locate impulsive atmospheric sources with a yield of at least one kiloton by detecting and characterizing the airborne infrasound radiated by the source. The infrasonic processing subsystem forms part of a larger system currently under development at the Prototype International Data Center (PIDC) in Arlington, Virginia where seismic, hydroacoustic, radionuclide and infrasonic methods are used to detect and locate impulsive sources in any terrestrial environment. Infrasonic signal detection is achieved via a coincidence detector which requires both the normalized cross correlation and the short-term-average/long-term-average ratio of a beam in the direction of maximum correlation to exceed predetermined threshold values simultaneously before a detection is declared. The infrasound propagation model currently used to infer travel-time information assumes the horizontal sound speed across the ground to be 320.0?m/s. This crude model is currently being replaced by a model which predicts travel-time information through a ray-tracing algorithm for acoustic waves in an atmosphere with seasonal representations for temperature and wind. A novel feature of the source location process is the fusion of all available arrival information, whether it be seismic, hydroacoustic or infrasonic to locate a single source where it is reasonable to hypothesize a common source. In its final configuration the infrasonic subsystem will routinely process data from the global 60-station International Monitoring System (IMS) infrasonic network currently under development. 相似文献
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935.
This paper was presented at the International Conference on Modelling of Global Climate Change and Variability, held in Hamburg 11–15 September 1989 under the auspices of the Meteorological Institute of the University of Hamburg and the Max Planck Institute for Meteorology. Guest Editor for these papers is Dr. L. Dumenil 相似文献
936.
937.
Frau Dr. M. M. Bezzegh Prof. Dr. H. L. Le Roy K. Steiner 《Aquatic Sciences - Research Across Boundaries》1977,39(2):201-225
Tritium of thermonuclear origin was measured in four different depth profiles in the Lake of Lucerne. Its concentration distribution yielded information on the mixing within the water mass under observation. A simple model was established for approximating the age structure of the water layers. 相似文献
938.
Vulcano, the southern Aeolian Island, is in fumarolic activity. The possibilities of measurements are limited by the field conditions as well as by the technological feasibility. In the presente work different tests were made in the field to measure temperature continuously: only the measurements made in dry steam gave good results because they avoid corrosion, and solution of the acid gases in the condensed in the ground. Field measurement show that the heat transfer is mainly due to convection. The values obtained in the field can be used to quantify the remote sensing of heat transfer. 相似文献
939.
Erta'ale lava lake: heat and gas transfer to the atmosphere 总被引:1,自引:0,他引:1
Data on uncontaminated samples of volcanic gases can be counted on the fingers of one hand, yet estimation of total volcanic gas flow cannot be made without such data. In this paper the flux of gas from the lava lake to the atmosphere is calculated by a heat budget based on the excess heat loss caused by combustion of H2 and CO and by the mass rate of loss of other gases on the basis of their ratios to H2 and CO in the unoxidized gas samples. The estimated rates of loss of H2O, CO2, SO2 and HCl are consistent with the rate of loss of heat if this heat is generated by crystallization and if the initial magma contains concentrations of gas appropriate for submarine basalt from oceanic ridges. The moderate activity of permanent degassing from the two active lava ponds studied gives a lower flux than that of other volcanoes. 相似文献
940.