排序方式: 共有86条查询结果,搜索用时 626 毫秒
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Loop Current Frontal Eddies (LCFE) in the Gulf of Mexico are simulated with a regional configuration of the Princeton Ocean Model using a feature-oriented initialization technique. The initialization procedure is based on a prior investigation of stability characteristics of the Loop Current (LC). Zonal channel experiments conducted with a multi-layer intermediate equations model allowed to identify conditions necessary for formation and growth of frontal eddies. The simulations were able to reproduce key features of LCFE-topography interaction in the DeSoto Canyon region observed during the “Eddy Intrusion” study. 相似文献
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V.L. Frolov L.M. Erukhimov S.A. Metelev E.N. Sergeev 《Journal of Atmospheric and Solar》1997,59(18):2317-2333
Features of artificial small-scale ionospheric irregularities (ASI) induced at F-region heights by powerful HF waves are discussed. The investigations presented here were performed during the past two decades at the Zimenki and Sura heating facilities, located at middle latitudes near Nizhniy Novgorod, Russia, as well as at the Gissar facility located at a lower latitude near Dushanbe, Tadzhikistan. The measurements were made by a variety of diagnostic methods employing artificial field-aligned scattering of HF and VHF radio waves, sounding of the disturbed region by means of low-power probing waves and testing of the artificial turbulence by means of stimulated electromagnetic emission (SEE). The dependence of ASI on such parameters as transverse scale length of the artificial irregularities, their location in the disturbed region, the power of the heating wave, the duration of HF radiation, geophysical conditions, aftereffects of the preceding modification, and the schedule of heater operation is considered for both the development stage after pump turn-on and the decay stage after pump turn-off. The temporal evolution of ASI spectral characteristics during the heater period is discussed. An empirical model for the ASI, based on the data available, was elaborated and verified by computer simulation of SEE generation. 相似文献
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E.N. Sergeev V.L. Frolov G.P. Komrakov B. Thidé T. Carozzi 《Journal of Atmospheric and Solar》1997,59(18):2383-2400
Experimental results concerning the growth and decay times of different spectral components of stimulated electromagnetic emission (SEE) are presented. A new method of measurement, employing a special pulsed pump scheme for the ionospheric plasma modification, has been elaborated and applied for studying HF-induced processes with high time resolution. The measurements performed show that the development and relaxation of different SEE features have an intricate pattern which depends on the emission frequency shift from the pump frequency, on the proximity of the pump frequency to the gyroharmonic frequencies, on the intensity of artificial ionospheric turbulence, and on the ionospheric conditions. The scope of this method for studies of HF plasma turbulence is discussed. 相似文献
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Timokhov L. A. Ivanov V. V. Kassens H. Lebedev N. V. Frolov I. Ye. Hölemann J. 《Doklady Earth Sciences》2018,480(1):685-688
Doklady Earth Sciences - According to historical oceanographic data, anomalies in the dynamic topography during the winter period were calculated and two climatic stages of dynamic condition of the... 相似文献
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V. N. Frolov Yu. K. Ananjevskaja D. L. Gorshanov E. V. Polyakov 《Astronomy Letters》2010,36(5):338-348
We present the results of our comprehensive study of the Galactic open star cluster NGC 6866. The positions of stars in the
investigated region have been obtained with the “Fantasy” automatic measuring machine from 10 plates of the normal astrograph
at the Pulkovo Astronomical Observatory. The size of the investigated field is 40′ × 40′, the limiting magnitude is B ∼ 16·
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6, and the maximum epoch difference is 79 yr. For 1202 field stars, we have determined the relative proper motions with an
rms error of 2.5 mas yr−1. Out of them, 423 stars may be considered cluster members with a probability P > 70% according to the astrometric criterion. Photometric diagrams have been used as an additional criterion. We have performed
two-color BV CCD photometry of stars with the Pulkovo ZA-320M mirror astrograph. The U magnitudes from the literature have also been used to construct the two-color diagrams. A total of 267 stars have turned
out to be members of NGC 6866 according to the two criteria. We present refined physical parameters of the cluster and its
age estimate (5.6 × 108 yr). The cluster membership of red and blue giants, variable, double, and multiple stars is considered. We have found an
almost complete coincidence of the positions of one of the stars in the region (a cluster nonmember) and a soft X-ray source
in the ROSAT catalog. The “Fantasy” automatic measuring machine is described in the Appendix. 相似文献
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A. M. Nikishin K. O. Sobornov A. V. Prokopiev S. V. Frolov 《Moscow University Geology Bulletin》2010,65(1):1-16
This paper presents characteristics of the structural regions surrounding the Siberian Platform and discusses the Vendian-present
time evolution of the Siberian Paleocontinent with the Siberian Craton making up its nucleus. It shows that the paleocontinent
underwent significant intraplate compressional deformations with vertical movements and formation of inversion structural
features within broad areas. Such epochs of deformation took place at the Riphean-Vendian time boundary, during the Late Paleozoic,
Late Triassic, Early Cretaceous, and during the Late Cenozoic. The principal rifting events took place during the Middle-Late
Devonian. The paper presents paleotectonic reconstructions of East Siberia at several key time intervals. 相似文献
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Yu. A. Gorbunov L. N. Dyment S. M. Losev S. V. Frolov 《Russian Meteorology and Hydrology》2008,33(9):594-599
A brief characteristic of the Arctic ice cover discontinuities (ICD) is given. Their practical importance for vessels operating in this region as well as necessity of forecasting such indicators as the prevailing disposition of discontinuities and location of zones of their formation and closure are noted. The forecasting technique is based on the method of complex analogs. A summary of forecasts produced for the Arctic navigation areas since 1991 is provided. It is shown, that recent upgrading of the original methodology allowed to produce forecasts in on-line mode, to present digital maps of the forecast data, and to transfer them directly to the vessel’s automated workplace. A number of practical examples are presented for illustrating the navigation efficiency if forecast and actual ICD data are used. The results of forecast verification are given. 相似文献