The impact of the spatial variability in bottom roughness on tidal dynamics and energetics, a case study: the M 2 surface tide in the North European Basin     

Boris A. Kagan  Ekaterina V. Sofina  Ebrahim Rashidi 《Ocean Dynamics》2012,62(10-12):1425-1442

A modified version of the 3D finite-element hydrostatic model QUODDY-4 is used to quantify the changes in the dynamics and energetics of the M ₂ surface tide in the North European Basin, induced by the spatial variability in bottom roughness. This version differs from the original one, as it introduces a module providing evaluation of the drag coefficient in the bottom boundary layer (BBL) and by accounting for the equilibrium tide. The drag coefficient is found from the resistance laws for an oscillatory rotating turbulent BBL over hydrodynamically rough and incompletely rough underlying surfaces, describing how the wave friction factor as well as other resistance characteristics depend on the dimensionless similarity parameters for the BBL. It is shown that the influence of the spatial variability in bottom roughness is responsible for some specific changes in the tidal amplitudes, phases, and the maximum tidal velocities. These changes are within the model noise, while the changes in the averaged (over a tidal cycle) horizontal wave transport and the averaged dissipation of barotropic tidal energy may be of the same orders of magnitude as are the above energetic characteristics as such. Thus, contrary to present views, ignoring the spatial variability in bottom roughness at least in the North European Basin is only partially correct: it is valid for the tidal dynamics, but is liable to break down for the tidal energetics.  相似文献   

Hydrology needed to manage droughts: the 2015 European case   总被引：1，自引：0，他引：1       下载免费PDF全文

Henny A.J. Van Lanen  Gregor Laaha  Daniel G. Kingston  Tobias Gauster  Monica Ionita  Jean‐Philippe Vidal  Radek Vlnas  Lena M. Tallaksen  Kerstin Stahl  Jamie Hannaford  Claire Delus  Miriam Fendekova  Luis Mediero  Christel Prudhomme  Ekaterina Rets  Renata J. Romanowicz  Sébastien Gailliez  Wai Kwok Wong  Mary‐Jeanne Adler  Veit Blauhut  Laurie Caillouet  Silvia Chelcea  Natalia Frolova  Lukas Gudmundsson  Martin Hanel  Klaus Haslinger  Maria Kireeva  Marzena Osuch  Eric Sauquet  James H. Stagge  Anne F. Van Loon 《水文研究》2016,30(17):3097-3104

  相似文献   

Assessing the extent of induced leakage to an urban aquifer using environmental tracers: an example from Bishkek, capital of Kyrgyzstan, Central Asia   总被引：2，自引：1，他引：1  

Brian L. Morris  W. George Darling  Daren C. Gooddy  Rafael G. Litvak  Ilka Neumann  Ekaterina J. Nemaltseva  Inna Poddubnaia 《Hydrogeology Journal》2006,14(1-2):225-243

A groundwater residence time study of the deep fluvioglacial aquifer supplying Bishkek, capital of Kyrgyzstan, has found evidence of deep infiltration of recent recharge both in the main periurban wellfield and below the city. Commonly-employed hydrochemical markers detected urban influence in the city-centre to depths of 65–100 m, but gave no indication of the important role of induced river/canal bed leakage, either upgradient in the periurban wellfield or within the city. This was revealed by O and H stable isotope measurements, which showed that local rainfall/snowfall play little part in the aquifer water balance. More remarkably, the universal detection of CFCs and SF₆, including in boreholes with 140–220 m deep upper screens, demonstrated that induced leakage of water just a few decades old had penetrated much deeper into the aquifer system than other hydrochemical markers indicated. A two-dimensional flow model set up to test whether such deep pumping-induced leakage could occur below the periurban wellfield confirmed its feasibility. The results imply vertical infiltration rates of 5–10 m/year and demonstrate that in this not-uncommon intergranular aquifer setting, deep boreholes with deep screen settings do not necessarily abstract old water. Hence, there are major implications for urban groundwater management and protection in such settings.

---

Resumen Un estudio sobre el tiempo de residencia del agua subterránea, en un acuífero fluvioglacial profundo que abastece a Bishkek, capital de Kyrgyzstan, ha encontrado evidencias de infiltración profunda a partir de recarga reciente, tanto en el campo de pozos de las afueras de la ciudad, como también por debajo de la ciudad. Los indicadores hidroquímicos comúnmente usados, detectaron influencia urbana en el centro de la ciudad hasta profundidades de 65–100 m, pero no dieron indicación del papel importante del goteo inducido en el lecho del canal/río, tanto aguas arriba en el campo de pozos de los suburbios, como también dentro de la ciudad. Esto se reveló mediante mediciones de isótopos estables de O y H, las cuales mostraron que las precipitaciones/nevadas de tipo local, tienen una pequeña contribución en el balance de agua del acuífero. De manera más notoria, la detección universal de CFCs y SF6, incluidos en las rejillas superiores de pozos profundos con 140–220 m de profundidad, demostraron que un goteo inducido de agua, de solo unas pocas décadas de antigüedad, ha penetrado mucho más profundo dentro del sistema acuífero, de lo que los otros marcadores hidroquímicos indicaban. Un modelo bidimensional de flujo, realizado para probar si el goteo inducido—bombeo profundo podía suceder debajo del campo de pozos suburbano, confirmó su factibilidad. Los resultados implican tasas de infiltración vertical de 5 a 10 m/año, y demuestran que los pozos profundos con tramos de rejilla también profundos, no necesariamente extraen aguas antiguas, en estos ambientes acuíferos con porosidad intergranular. Por lo tanto, hay implicaciones importantes para la gestión y protección en zonas urbanas, y para esos ambientes de las aguas subterráneas.

---

Résumé Lanalyse du temps de résidence des eaux souterraines dans un aquifère fluvial profond, dorigine glaciaire, qui alimente en eau Bishek, la capitale de Kyrgyzstan a mis en évidence une recharge récente tant dans le captage en eau que sous la ville même. Les traceurs chimiques ont indiqué linfluence urbaine dans le centre de la ville, à une profondeur de 65–100 m, mais ils nont pas mis en évidence le rôle important de lalimentation induite par la couche du fleuve, tant en amont, dans le captage que en aval, dans la ville. Ces effets ont été relevés par des isotopes stables, comme O et h qui ont montré linfluence récente des précipitations dans le bilan hydrique de laquifère. De plus, la détection universelle de CFC et de SF6, y compris dans les forages ayant une profondeur de 140–220 m, montre que lalimentation en eau induite de plusieurs décennies a pénétré à des profondeurs plus grandes que celles indiqués par des traceurs chimiques. Les possibilités dune drainance verticale induite par les pompages dans le puits profonds du captage ont été vérifiées par un modèle bidimensionnel découlement. Les résultats de la modélisation ont conduit à une infiltration verticale de 5–10 m/an et ont démontré aussi que leau extraite par des puits profonds dans un aquifère granulaire nest pas nécessairement dage ancienne. Il sagit donc des implications majeures concernant la gestion et la protection des captages urbaines en eaux souterraines

  相似文献   

Water interaction with MgCl<Subscript>2</Subscript>×6H<Subscript>2</Subscript>O and NaCl surfaces: measurements of the uptake coefficient     

Yuri Bedjanian  Ekaterina Loukhovitskaya 《Journal of Atmospheric Chemistry》2009,63(2):97-108

The uptake of water vapor on MgCl₂×6H₂O and NaCl salt dry solid films was studied over the temperature range 240 to 340 K and at 1 Torr pressure of helium using a flow reactor coupled to a modulated molecular beam mass spectrometer. The H₂O to salt uptake data were obtained from the kinetics of H₂O loss on salt coated Pyrex rods. The following Arrhenius expression was obtained for the initial uptake coefficient of H₂O on MgCl₂×6H₂O films: γ ₀ (MgCl₂) = (6.5 ± 1.0) × 10⁻⁶ exp[(470 ± 40)/T] (calculated with specific BET surface area, quoted uncertainties are 1σ statistical). The rate of H₂O adsorption on NaCl was found to be much lower than on MgCl₂×6H₂O, and only an upper limit was determined for the corresponding uptake coefficient: γ (NaCl) ≤ 5.6 × 10⁻⁶ at T = 300 K. The results show that the rate of H₂O adsorption to salt surfaces is drastically dependent on the salt sample composition.  相似文献   

Effect of temperature on contents of essential highly unsaturated fatty acids in freshwater zooplankton     

Michail I. Gladyshev  Vitaliy P. Semenchenko  Olga P. Dubovskaya  Elena B. Fefilova  Olesia N. Makhutova  Zhanna F. Buseva  Nadezhda N. Sushchik  Vladimir I. Razlutskij  Ekaterina V. Lepskaya  Mariya A. Baturina  Galina S. Kalachova  Olga N. Kononova 《Limnologica》2011,41(4):339-347

In 11 lakes from cold and warm regions we studied the content of highly unsaturated fatty acids (HUFA) in seston (<130 μm) and crustacean zooplankton using gas chromatography–mass spectrometry. An increase of temperature correlated with a decrease of HUFA content in zooplankton. A multivariate canonical correlation analyses revealed, that the decrease of HUFA content was related with a decrease of per cent of copepods in zooplankton communities, which are known to have higher HUFA levels in their biomass, than cladocerans. This means that temperature primarily affected the HUFA levels indirectly, via changing of taxonomic structure of zooplankton community, while the homeoviscous adaptation of zooplankton individuals had comparatively lower importance. As found, water temperature was better predictor of HUFA contents of zooplankton, than the fatty acid composition of seston. Thus, it can be predicted, that a probable climate warming will decrease the content of the essential HUFA in freshwater zooplankton with possible negative consequences for animals of higher trophic levels.  相似文献   

40Ar/39Ar dating and cosmic‐ray exposure time of desert meteorites: Dhofar 300 and Dhofar 007 eucrites and anomalous achondrite NWA 011     

Ekaterina V. Korochantseva  Mario Trieloff  Alexei I. Buikin  Jens Hopp  Hans‐Peter Meyer 《Meteoritics & planetary science》2005,40(9-10):1433-1454

Abstract— We performed high‐resolution ⁴⁰Ar‐³⁹Ar dating of mineral separates and whole‐rock samples from the desert meteorites Dhofar 300, Dhofar 007, and Northwest Africa (NWA) 011. The chronological information of all samples is dominated by plagioclase of varying grain size. The last total reset age of the eucrites Dhofar 300 and Dhofar 007 is 3.9 ± 0.1 Ga, coeval with the intense cratering period on the Moon. Some large plagioclase grains of Dhofar 007 possibly inherited Ar from a 4.5 Ga event characteristic for other cumulate eucrites. Due to disturbances of the age spectrum of NWA 011, only an estimate of 3.2–3.9 Ga can be given for its last total reset age. Secondary events causing partial ⁴⁰Ar loss ≤3.4 Ga ago are indicated by all age spectra. Furthermore, Ar extractions from distinct low temperature phases define apparent isochrons for all samples. These isochron ages are chronologically irrelevant and most probably caused by desert alterations, in which radiogenic ⁴⁰Ar and K from the meteorite and occasionally K induced by weathering are mixed, accompanied by incorporation of atmospheric Ar. Additional uptake of atmospheric Ar by the alteration phase(s) was observed during mineral separation (i.e., crushing and cleaning in ultrasonic baths). Consistent cosmic‐ray exposure ages were obtained from plagioclase and pyroxene exposure age spectra of Dhofar 300 (25 ± 1 Ma) and Dhofar 007 (13 ± 1 Ma) using the mineral's specific target element chemistry and corresponding ³⁸Ar production rates.  相似文献   

X-ray single-crystal and Raman study of (Na<Subscript>0.86</Subscript>Mg<Subscript>0.14</Subscript>)(Mg<Subscript>0.57</Subscript>Ti<Subscript>0.43</Subscript>)Si<Subscript>2</Subscript>O<Subscript>6</Subscript>, a new pyroxene synthesized at 7 GPa and 1700 °C     

Ekaterina A. Sirotkina  Andrey V. Bobrov  Anna V. Spivak  Luca Bindi  Dmitry Yu. Pushcharovsky 《Physics and Chemistry of Minerals》2016,43(10):731-738

A new pyroxene with formula (Na_0.86Mg_0.14)(Mg_0.57Ti_0.43)Si₂O₆, synthesized in a high-pressure toroidal ‘anvil-with-hole’ apparatus at P = 7 GPa and T = 1700 °C, was characterized by X-ray single-crystal diffraction and Raman spectroscopy. The compound was found to be monoclinic (R1 = 2.56 %), space group C2/c, with lattice parameters a = 9.687(2), b = 8.814(1), c = 5.290(1) Å, β = 107.853(2)°, V = 430.08(1) ų. The coexistence of Mg and Ti⁴⁺ at the M1 site does not induce strong modifications either to the M1 site or to the adjacent M2 site. The Raman spectrum of synthetic Na–Ti-pyroxene was obtained for the first time and compared with that of Mg₂Si₂O₆ (with very low concentrations of Na and Ti). The structural characterization of the Na–Ti–Mg-pyroxene is important, because the study of its thermodynamic constants provides new constraints on thermobarometry of the upper mantle assemblages.  相似文献   

Polyatomic Interferences Produced by Macroelements During Direct Multi-Elemental ICP-MS Hydrochemical Analysis     

Vladimir N. Epov  Dominic Lariviere  Ekaterina N. Epova  R. Douglas Evans 《Geostandards and Geoanalytical Research》2004,28(2):213-224

An experimental study of the interferences produced by macroelements (Na, K, Ca, Mg, Sr, S, Cl, Si, N and C) contained in natural waters during inductively coupled plasma-mass spectrometry (ICP-MS) is presented. The most significant interferences created by these elements were found to be SO, CO, CAr, SiH, SiO, NaH, NaAr, MgAr, CaO, KO and KAr, the magnitude of which was dependant on the concentration of each macroelement. To reduce these interferences, different approaches, for example, desolvating nebulisation, high resolution and dynamic reaction cell ICP-MS were applied and compared. All three approaches were found to be useful tools for significantly reducing various polyatomic interferences. Advantages and disadvantages for each approach are discussed.  相似文献   

Cyclonic circulation and upwelling in Lake Baikal   总被引：1，自引：0，他引：1  

Elena Troitskaya  Vadim Blinov  Vyacheslav Ivanov  Andrey Zhdanov  Ruslan Gnatovsky  Ekaterina Sutyrina  Mikhail Shimaraev 《Aquatic Sciences - Research Across Boundaries》2015,77(2):171-182

  相似文献   

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