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51.
Vladimir V. Ivanov Igor V. Polyakov Igor A. Dmitrenko Edmond Hansen Irina A. Repina Sergey A. Kirillov Cecillie Mauritzen Harper Simmons Leonid A. Timokhov 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(1):1-14
A combination of 2-year-long mooring-based measurements and snapshot conductivity–temperature–depth (CTD) observations at the continental slope off Spitsbergen (81°30′N, 31°00′E) is used to demonstrate a significant hydrographic seasonal signal in Atlantic Water (AW) that propagates along the Eurasian continental slope in the Arctic Ocean. At the mooring position this seasonal signal dominates, contributing up to 50% of the total variance. Annual temperature maximum in the upper ocean (above 215 m) is reached in mid-November, when the ocean in the area is normally covered by ice. Distinct division into ‘summer’ (warmer and saltier) and ‘winter’ (colder and fresher) AW types is revealed there. Estimated temperature difference between the ‘summer’ and ‘winter’ waters is 1.2 °C, which implies that the range of seasonal heat content variations is of the same order of magnitude as the mean local AW heat content, suggesting an important role of seasonal changes in the intensity of the upward heat flux from AW. Although the current meter observations are only 1-year long, they hint at a persistent, highly barotropic current with little or no seasonal signal attached. 相似文献
52.
G. V. Polyakov A. E. Izokh A. V. Vishnevskii A. V. Travin 《Doklady Earth Sciences》2010,433(1):856-860
The new petrochemical and isotope-geochronological characteristics for picritoid and associated alkali-basaltic complexes
of the Northern Mongolian Belt (NMB) are given. They are composed in small intrusions, dykes, sills, and volcanic covers with
rocks of a higher potassium and titanium content. The studied areas with these units belonged to the western part of the NMB,
which stretches sublatitudinally from Uureg Nuur Lake in the west to the south of Trans-Hovsgol Region in the east. By the
petrochemical parameters, the complex corresponds to subalkaline basites and lamprophyres, including micaceous plagioperidotites
and picrodolerites. The obtained values of Ar-Ar age (342–319 Ma B.P.), together with the known data on other areas in this
complex where these rocks are distributed, evidences for a relatively wide (Middle-Late Paleozoic) interval of its origination. 相似文献
53.
A. V. Polyakov Yu. M. Timofeyev A. B. Uspensky 《Izvestiya Atmospheric and Oceanic Physics》2011,47(9):1092-1096
Numerical experiments on the simultaneous retrieval of the temperature and spectral emissivity of different land types are
performed on the basis of inversion of the simulated high spectral resolution measurements by the IRFS-2 satellite IR sounder.
The IRFS-2 data inversion method is based on using a priori information on the spectral behavior of emissivity of different
land types and the multiple linear regression technique. The rms errors of determination of the underlying surface temperature
using different solving operators are 0.26–0.71 K. The application of the developed IRFS-2 measurement inversion method makes
it possible to estimate the land surface emissivity with an rms error not larger than 0.015. 相似文献
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Variations in the Hydrological Regime of Kara-Bogaz-Gol Gulf,Lake Issyk-Kul,and the Aral Sea Assessed Based on Data of Bottom Sediment Studies 总被引:1,自引:0,他引:1
Ferronskii V. I. Polyakov V. A. Brezgunov V. S. Vlasova L. S. Karpychev Yu. A. Bobkov A. F. Romaniovskii V. V. Johnson T. Ricketts D. Rasmussen K. 《Water Resources》2003,30(3):252-259
The isotopic and material composition of bottom deposits, examined in the Kara-Bogaz-Gol Gulf, Lake Issyk-Kul, and the Aral Sea, is considered. The obtained data are used to characterize variations in the regime of the water bodies in the Holocene. 相似文献
58.
N. M. Firstova V. I. Polyakov V. I. Skomorovsky V. M. Grigoriev 《Geomagnetism and Aeronomy》2009,49(7):927-934
Impact linear polarization in solar flares is studied with the Large Solar Vacuum Telescope (LSVT) using the spectral polarimetric
method. This method makes it possible to minimize the effect of instrumental polarization with an error of up to 10−2 owing to the normalization of the spectral line intensity to the continuum spectrum intensity with negligible linear polarization.
As a result, the Hα line intensity in two orthogonally polarized spectral stripes coincides in the absence of solar polarization.
However, in the presence of linear polarization in a flare, the spectral polarimetric method does not rule out that the error
can be present in determining the Stokes parameters Q and U because of their possible relative “leakage.” Linear instrumental polarization of LSVT has been performed using polaroid
rotation before the major mirror. Twelve elements of a telescope matrix, characterizing linear polarization, have been determined.
The usage of a matrix makes it possible to specify the observed Q and U values accurate to 10−3 of their magnitude. 相似文献
59.
Li Li Mark A. Nearing Mary H. Nichols Viktor O. Polyakov Michelle L. Cavanaugh 《地球表面变化过程与地形》2020,45(2):484-495
Terrestrial LiDAR scanning (TLS) technology is widely used to detect terrain elevation changes. This study examines the potential use of terrestrial LiDAR to measure erosion on small experimental plots at high resolution. Multitemporal TLS scans were conducted at six positions around plots (12 m2) with three slope treatments through 11 simulated rainfall applications. Surface elevation changes were quantified by comparing scans between rainfall simulations, and elevation changes greater than the level of detection were used to obtain volumetric change estimations. Erosion mass was estimated both by using soil bulk density and the density of sediment collected in runoff, and then compared to the erosion estimated from the runoff samples. Results showed: (1) with the aid of fixed reference controls in the form of concrete target surfaces of varying roughness, registration accuracy was better than 1 mm and mean level of change detection was less than 2.2 mm; (2) the average absolute relative errors of TLS-estimated eroded mass ranged from 6.8% to 31.8%, with greater values on 5% slope; (3) the TLS-estimated erosion accuracy was affected by erosion magnitude, the utilized material density and number of scan positions, and a grid size of 10 mm was found to be appropriate for this scale to estimate the volumetric changes; (4) the number of scan positions could be reduced to three while not significantly impacting volumetric change estimations; and (5) elevating the scanner resulted in much better accuracy for eroded mass estimations. This study suggests that using LiDAR to monitor soil erosion at the plot scale is feasible, and provides guidance about the level of accuracy one might expect in doing so. © 2019 John Wiley & Sons, Ltd. 相似文献
60.
A new, multi‐tracer method is used to track erosion, translocation, and redeposition of sediment in a small watershed, thus allowing for the ?rst time a complete, spatially distributed, sediment balance to be made as a function of landscape position. A 0·68 ha watershed near Coshocton, Ohio, USA was divided into six morphological units, each tagged with one of six rare earth element oxides. Sediment translocation was evaluated by collecting run‐off and by spatially sampling the soil surface. Average measured erosion rate was 6·1 t ha?1, but varied between 40·4 t ha?1 loss from the lower channels to 24·1 t ha?1 gain on the toeslope. With this technique it was possible for the ?rst time to itemize the sediment budget for landscape elements into three components: (1) the soil from the element that left the watershed with run‐off; (2) soil from the element that was redeposited on lower positions, with the spatial distribution of that deposition; and (3) soil originating from the upper positions and deposited on the element, with quanti?cation of relative source areas. The results are incongruous with the current morphology of the watershed, suggesting that diffusion‐type erosion must also play a major role in de?ning the evolution of this landscape. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献