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921.
The authors describe the principles and method used in compiling a map of game animal resources for the Midlands region, the name given to the middle segment of the Soviet Union comprising West Siberia, Kazakhstan and Central Asia. The results make it possible to recommend the optimal use of game resources and to identify future prospects of the trapping and hunting economy. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1982, No. 5, pp. 17-23. 相似文献
922.
A. Vandenbohede L. Lebbe Stefaan Gysens Kevin Delecluyse Peter DeWolf 《Journal of Hydrology》2008,360(1-4):77-86
In the dune area of the Westhoek Nature Reserve, situated in the western Belgian coastal plain, two artificial tidal inlets were made aiming to enhance biodiversity. The infiltration of salt water in these tidal inlets was carefully monitored because a fresh water lens is present in the phreatic dune aquifer. This forms an important source of fresh water which is for instance exploited by a water company. The infiltration was monitored over a period of two years by means of electromagnetic borehole measurements (EM39) and by measurements of fresh water heads and temperature using a large number of observation wells. EM39 observations point to aquifer heterogeneity as a determining factor in the movement of the salt infiltration water. It is shown that part of the infiltration water moves further in the dunes instead of towards the sea. On the long term run, possibility exists that salt water enters the extraction’s capture zone. This issue needs further monitoring and study. Fresh water head and temperature data illustrate that the main period of infiltration is confined to spring tide when large amounts of salt water enter the tidal inlets. 相似文献
923.
Contribution of momentum advection to the formation of the low frequency fields of the Baltic Sea levels and currents is estimated using numerical experiments with a hydrodynamic model and statistical analysis of the experimental results. It is found that momentum advection has a significant influence on the formation of the mean level and its seasonal and synoptic variability in Neva Bay of the Gulf of Finland. The results show that nonlinear effects associated with advective accelerations can essentially contribute to the Neva River flood formation. 相似文献
924.
The c. 1·2 km long, up to c. 25 m high ridge east of the almost north-south aligned Fan Hir scarp, Mynydd Du, South Wales has been regarded as a remarkable protalus rampart formed in the Loch Lomond Stadial (c. 11–10000 years BP ). New data are presented which indicate that it is a moraine. The main points supporting this glacigenic origin are: its curved plan form at the lower, southern end; its scale and the ample depth for snow to glacier ice transformation; the presence of subsidiary ridges interpreted as recessional moraines; the exceptional rate of rockwall retreat required if it were a protalus rampart; and, most importantly, the presence in the ridge of matrix-supported abraded clasts, up to 20% of which are striated. Useful criteria for differentiating moraines and protalus ramparts are thereby proposed and a sound basis is provided for palaeoclimatic reconstruction. Palaeoclimatic inferences imply that the glacier owed its existence to the combined effect of a mean July temperature of c. 8·5°C and topographically enhanced accumulation, nearly half of which was from wind-blown snow. 相似文献
925.
A. M. Berlyant 《地理信息系统科学与遥感》2013,50(3):175-188
The history of the joint use of maps and air photos/space imagery in geographic problem solving is examined, as are general problems which must be addressed before more complete consolidation of map use and image interpretation methods will be possible. The relatively new field of geoiconics, encompassing image theory, processing, and interpretation, is proposed as a branch of knowledge promoting the integration of cartography and remote sensing rather than a megafield that will ultimately replace them. Translated from: Geografiya i prirodnyye resursy, 1985, No. 4, pp. 11-22. 相似文献
926.
927.
The area of sea subjected to heated effluent discharged from the power station at Piombino is very suitable for the study of problems connected with thermal pollution of the nearshore environment. Construction of the power station is planned to go ahead by successive operational stages, producing correspondingly increased amounts of heat discharged into the marine environment. At present it produces 640 MW and discharges 190 Mcal s?1 into the sea.This paper studies the benthic communities after the power station had been operating for about 1 yr. Comparison of these data with those about subsequent operational stages will presumably allow to establish to what extent the environment can receive, without damage, increasing amounts of heat. 相似文献
928.
J. A. R. Blais 《Journal of Geodesy》1996,70(6):349-356
Summary Given a sample autocovariance sequence of finite length for some observed random process, the spectrum estimation problem involves the extension of this sequence for the required Fourier transformation. The maximum entropy approach which is based on the optimal use of information contents, leads to a dual sequence of reflection coefficients with reciprocal spectrum of the process. The estimation of the maximum entropy spectrum implies results identical to those using autoregressive modeling in one dimension under appropriate white noise assumptions. In cases of a non-white noise component, the approach is generalized to an autoregressive-moving-average model. Recent developments in multiresolution analysis with spectral domain decompositions also offer possibilities of subband spectrum estimation for specific applications. Using a simulated data sequence with two close frequencies, the estimated spectrum from a two-level decomposition with autoregressive modeling shows better resolution than with conventional processing. Geodetic and geophysical applications are briefly indicated. 相似文献
929.
K. V. Sanil Kumar P. V. Hareesh Kumar 《Journal of the Indian Society of Remote Sensing》2005,33(1):137-146
Eddies and planetary waves are identified as one of the important factors that control the dynamics of the Arabian Sea. During
10–14 January 1990, Ignat, Paulyuchenkov (USSR ship) conducted an experiment in the central Arabian Sea and of late TOPEX/POSEIDON
satellites collected data on sea surface height (SSH) anomalies of the Arabian Sea. These data sets give an opportunity to
understand the characteristic of eddies and planetary waves in this region during winter. The geostrophic flow revealed three
anticyclonic and two cyclonic eddies of diameters ranging from 75 to more than 150 km from surface to subsurface levels. Current
speeds around different eddies were maximum at surface and varied from 9 cm/s to 25 cm/s (at the middle point between the
center and periphery). The occurrence of eddies were further investigated with the TOPEX/POSEIDON altimetry for the years
1993–97. The analysis revealed multiple eddies of diameter 100 to 550 km occur every year with maximum number of eddies during
1997 and minimum during 1995. The calculated speed varied between 8–30 cm/s around various eddies.
Longitude-Time plots showed annual Rossby waves generating at the eastern Arabian Sea and propagating westwards with a phase
speed of ~ 10 cm/s along 16° N. Further, it was observed that these waves arrived in the study area by January. In addition,
another positive anomaly of SSH was found generating at the western Arabian Sea simultaneously and extended up to the study
region by April–June. Time series of SSH at selected locations along 16°N revealed many small-scale oscillations and their
spatial variability. These oscillations were delineated using the FFT analysis. Other than the Rossby wave, the major components
at the study region were 40–60 and 26–32 day oscillations. The implications of these long period waves associated with eddies
are discussed. 相似文献
930.
The growth rate and potential production of bacterioplankton in cold hydrocarbon seeps located along the Louisiana coast were determined using a pulse-labeling technique. Surprisingly, community doubling times are on the order of 1.1 h, which compares to laboratory-grown cultures. We also found that there are differences in growth rates on relatively small geographic scales, suggesting the influence of site-specific geological features (e.g., gas hydrate mounds). Proceeding downslope to deeper waters, methane-oxidizing bacteria appeared to play a more significant role in community productivity. These preliminary experiments indicated, quite unexpectedly, that water column microbes are growing at a more rapid rate than in any other marine system so far studied and that methane may serve as a primary nutrient (carbon) source in these seep-associated microbial assemblages. 相似文献