Atmospheric boundary layer over steep surface waves     

Yuliya Troitskaya  Daniil A. Sergeev  Oleg Druzhinin  Alexander A. Kandaurov  Olga S. Ermakova  Ekaterina V. Ezhova  Igor Esau  Sergej Zilitinkevich 《Ocean Dynamics》2014,64(8):1153-1161

Turbulent air-sea interactions coupled with the surface wave dynamics remain a challenging problem. The needs to include this kind of interaction into the coupled environmental, weather and climate models motivate the development of a simplified approximation of the complex and strongly nonlinear interaction processes. This study proposes a quasi-linear model of wind-wave coupling. It formulates the approach and derives the model equations. The model is verified through a set of laboratory (direct measurements of an airflow by the particle image velocimetry (PIV) technique) and numerical (a direct numerical simulation (DNS) technique) experiments. The experiments support the central model assumption that the flow velocity field averaged over an ensemble of turbulent fluctuations is smooth and does not demonstrate flow separation from the crests of the waves. The proposed quasi-linear model correctly recovers the measured characteristics of the turbulent boundary layer over the waved water surface.  相似文献   

Anisotropic elastic full‐waveform inversion of walkaway vertical seismic profiling data from the Arabian Gulf          下载免费PDF全文

John C Owusu  Marwan Charara  Scott Leaney  Allan Campbell  Shujaat Ali  Igor Borodin  Les Nutt  Henry Menkiti 《Geophysical Prospecting》2016,64(1):38-53

Borehole seismic addresses the need for high‐resolution images and elastic parameters of the subsurface. Full‐waveform inversion of vertical seismic profile data is a promising technology with the potential to recover quantitative information about elastic properties of the medium. Full‐waveform inversion has the capability to process the entire wavefield and to address the wave propagation effects contained in the borehole data—multi‐component measurements; anisotropic effects; compressional and shear waves; and transmitted, converted, and reflected waves and multiples. Full‐waveform inversion, therefore, has the potential to provide a more accurate result compared with conventional processing methods. We present a feasibility study with results of the application of high‐frequency (up to 60 Hz) anisotropic elastic full‐waveform inversion to a walkaway vertical seismic profile data from the Arabian Gulf. Full‐waveform inversion has reproduced the majority of the wave events and recovered a geologically plausible layered model with physically meaningful values of the medium.  相似文献   

Chilean Earthquakes: Aquifer Responses at the Russian Platform     

Alina Besedina  Evgeny Vinogradov  Ella Gorbunova  Igor Svintsov 《Pure and Applied Geophysics》2016,173(4):1039-1050

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Does Biot’s theory have predictive power?     

Igor A. Beresnev 《Pure and Applied Geophysics》2016,173(8):2671-2686

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A New Thermophoretic Precipitator for Off‐Line Particle Analysis     

Lucija Boskovic  Igor E. Agranovski 《洁净——土壤、空气、水》2012,40(6):565-570

A new thermophoretic particle precipitator has been developed for representative and efficient collection of aerosol particles from the ambient air and technological pipelines. The device consists of hot and cold plates (5 × 5 cm²) capable of operation at temperature gradients ranging from 20 000 to 100 000 K/m. A gas sample is made to pass through a 1‐mm slot between the plates at a flow rate of up to 1.5 L/min, which makes the device suitable for operation in conjunction with common aerosol instruments including DMA and diffusion batteries with similar operational flow rates. It was shown that the efficiency of the device was highest for the lowest gas flow rate used (0.3 L/min) reaching a level of above 99%. The efficiency was decreased reaching its minimal values at the highest flow rate investigated (1.5 L/min). However, even for highest flow rate, the average efficiency for removal of particle smaller than 60 nm was around 50%.  相似文献   

Meridional asymmetric distribution of the primary production in the Atlantic Sector of the Southern Ocean in the austral spring and summer     

A. B. Demidov  S. A. Mosharov  V. I. Gagarin 《Oceanology》2012,52(5):623-634

The spatial distribution of the phytoplankton productivity was investigated in the Atlantic Sector of the Southern Ocean in the austral summer of 2009?C2010 and the spring of 2010 on the basis of field measurements. In October?CNovember, the average integrated primary production and the concentration of surface and integrated (photosynthetic layer) chlorophyll ??a?? in the Subantarctic waters of the Drake Passage exceeded the similar values along the Greenwich meridian by 3, 2, and 1.5 times, respectively. Similar primary production was observed in December?CJanuary for the water column in the eastern and western sectors of the studied area. The chlorophyll ??a?? concentration in the surface water layer was higher by 1.7 times for the Greenwich meridian area compared to the deep layers, but the concentrations of this pigment in the deeper layers did not differ. During the spring, the average primary production in the water column (the chlorophyll ??a?? concentration in the surface and in the photosynthetic layer) differed in the Drake Passage and along the Greenwich meridian by 2.3, 1.6, and 1.7 times, respectively. The opposite pattern was observed during the summer period, when the parameters listed above were higher for the Greenwich meridian area by 1.9, 2.5, and 1.7 times, respectively. Therefore, the western Antarctic areas in the spring are characterized by higher production than the eastern ones, and an opposite pattern is observed in the summer. The possible reasons for the meridional zonation of the chlorophyll ??a?? and the primary production are discussed in regard to different seasons.  相似文献   

Detection of Mediterranean lenses in the Atlantic ocean by profilers of the Argo project     

A. N. Demidov  B. N. Filyushkin  N. G. Kozhelupova 《Oceanology》2012,52(2):171-180

We executed investigations of Mediterranean lenses detection in the Atlantic using data recorded by buoys-profilers of the “Argo” project (more than 11200 profiles). We investigate the region from 28° to 47° N and from 7° to 27° W for the period from 2001 to 2010. From these data, we revealed “lenses profiles” with the salinity values exceeding 36 psu (2043 cases). We demonstrate the allocation of Argo buoys in the area investigated and indicate their working periods; we also show the periodicity of the “lenses profiles.” It was found out that the Argo buoys traced individual lenses and depicted correctly their movements, the vertical scale of the eddy, its location in the depth, and the hydrological peculiarities of the lenses. We estimated the number of lenses occurring in different periods and analyzed the interaction of the Argo buoy with the intrathermocline lenses. The importance of these investigations for studying the Mediterranean water dynamics was pointed out.  相似文献   

Simultaneous measurements of the two-dimensional distribution of infrared laser intensity and temperature in a single-sided laser-heated diamond anvil cell     

Kamil M. Bulatov  Pavel V. Zinin  Yulia V. Mantrova  Aleksey A. Bykov  Maksim I. Gaponov  Alexsandr S. Machikhin  Ivan A. Troyan  Igor B. Kutuza 《Comptes Rendus Geoscience》2019,351(2-3):286-294

In this report, we demonstrate that combining the laser heating system in a diamond anvil cell (LH-DAC) with a tandem acoustic-optical tunable filter (LH-DAC–TAOTF) allows for the simultaneous measurement of (a) the relative infrared (IR, 1070 nm) power distribution on a specimen surface in the DAC; (b) the temperature distribution under laser heating of a specimen under high-pressure in a DAC; it also (c) provides an opportunity to control the shape of the IR laser spot on the surface of the heated specimen. The effect of the π-shaper on the shape and the position of the focus of the IR laser beam on a specimen using a TAOTF is also presented. For a 10× long-working distance objective, the smallest diameter of the IR laser was found to be around 10 μm, when the focal plane coincides with that of the imaging optical system of LH-DAC. The highest diameter of the IR laser was shown to be 20 μm when the rim of the π-shaper was set at 3 μm. It is demonstrated also that the TAOFT not only permits to measure the two-dimensional (2-D) distribution of the IR laser power, but also allows for the alignment of the laser before each heating event at different pressures.  相似文献   

Chronostratigraphy of Monte Vulture volcano (southern Italy): secondary mineral microtextures and <Superscript>39</Superscript>Ar-<Superscript>40</Superscript>Ar systematics     

Igor M. Villa  Annett Buettner 《Bulletin of Volcanology》2009,71(10):1195-1208

The eruptive history of Monte Vulture has been the subject of several geochronological investigations during the past decades, which reliably dated only a small number of eruptions. Understanding the causes of sub-optimum data yield in the past requires an interdisciplinary approach. We re-analyzed samples from previous works and present new data on samples from the main volcano-stratigraphic units of Monte Vulture, so as to provide an improved, consistent chronostratigraphic database. Imaging of minerals by cathodoluminescence and backscattered electrons reveals that heterochemical, high-temperature deuteric reaction textures are ubiquitous. Such observations are common in metamorphic rocks but had not frequently been reported from volcanic rocks. In view of the mineralogical complexity, we base our chronological interpretation on isochemical steps, defined as steps for which the Cl/K and/or the Ca/K ratios are constant. Isochemical steps carry the isotopic signature of chemically homogeneous mineral phases and therefore allow a well-constrained age interpretation. Comparison of old and new ³⁹Ar-⁴⁰Ar data proves the reproducibility of age spectra and their shapes. This quantifies the analytical reliability of the irradiation and mass-spectrometric analyses. Anomalous age spectra are a reproducible property of some specific samples and correlate with mineralogical anomalies. The present data allow us to fine-tune the age of the volcanostratigraphic units of Monte Vulture during the known interval of main volcanic activity from ca. 740 to 610 ka. After a very long stasis, the volcanic activity in the Monte Vulture area resumed with diatremic eruptions, one of which (Lago Piccolo di Monticchio, the site of a palynological-paleoclimatological drilling) was dated at ca. 140 ka.  相似文献   

Long-lasting Cadomian magmatic activity along an active northern Gondwana margin: U–Pb zircon and Sr–Nd isotopic evidence from the Brunovistulian Domain,eastern Bohemian Massif     

Soejono  Igor  Janoušek  Vojtěch  Žáčková  Eliška  Sláma  Jiří  Konopásek  Jiří  Machek  Matěj  Hanžl  Pavel 《International Journal of Earth Sciences》2017,106(6):2109-2129

International Journal of Earth Sciences - Cadomian magmatic complexes of the Brunovistulian Domain crop out at the eastern termination of the Bohemian Massif. However, the age, nature and...  相似文献