Acoustic reflectivity and shallow sedimentary structure in the Sea of Galilee, Jordan Valley     

Zvi Ben-Avraham  Gabriel Shaliv  Amos Nur 《Marine Geology》1986,70(3-4):175-189

Mapping the floor of the Sea of Galilee (Lake Kinneret) with a shallow seismic system of 3.5 kHz resulted in interesting data that were not obtained previously with standard single-channel seismic systems. Over most of the lake acoustic penetration is not possible, probably because of the high gas content in the top sedimentary sequence. However, in a few areas, excellent penetration of about 20 m was achieved. One area is a terrace in the southern part of the lake, south of a small bathymetric escarpment at depths of 13–21 m along Israel latitudinal Grid 238. It is unclear whether the existence of gas in the sediment or other parameters are responsible for the marked difference in acoustic penetration on both sides of the scarp.Another area with acoustic penetration is in the vicinity of hot and salty submarine springs. Although there is no difference in the composition of the upper sedimentary layers between these areas and neighbouring areas, there is a marked difference in the acoustic penetration. The contact between areas with acoustic penetration to areas without acoustic penetration is very sharp. The craters of the submarine springs are usually located on the borders of the areas with acoustic penetration or even at some distance away from them. It is possible that the activity of the hot and salty submarine springs controls the acoustic penetration. However, determination of the exact mechanism for the existence of the zones of acoustic penetration must await further studies of the sediments, especially for measurements of various parameters that control the seismic response of the rock.Another discovery made with the shallow seismic profiles is the existence of some bathymetric irregularities on the floor of the Sea of Galilee. In view of the high sedimentation rate in the lake, which tends to smooth the floor, a bathymetric irregularity such as a linear bathymetric step could be a surface expression of an active fault.  相似文献   

About some very small harmonics which are present in the tide of the Pacific     

Gabriel Godin  Ignacio Gonzalez 《Ocean Dynamics》1991,44(3):115-132

Summary Over 85% of the harmonic components of the tide along the west coast of Mexico have amplitudes smaller than 2 cm. Yet they are fully resolvable from the noise back-ground so that cotidal charts could be drawn for minor components such asQ ₁ andT ₂ . A cotidal chart forS ₁ ist also presented; the presence of this component is attributed not to the tidal forces but to some irregularity in the shape of the Earth or in the distribution of its mass. Third order effects of a magnitude of 1 to 9 mm are evident in the semidiurnal band; they actually exceed the second order input at some stations. The presence of compound harmonics of nonlinear origin, such as2MK ₂ ,MOK ₂ andNK ₃ is also detectable.

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Über einige sehr kleine harmonische Konstanten, die in den Gezeiten des Pazifiks vorkommen

Zusammenfassung Über 85% der harmonischen Komponenten entlang der Westküste von Mexiko haben Amplituden kleiner als 2 cm. Dennoch sind sie vollständig aus dem Hintergrundrauschen herauszufiltern, so daß für kleinere Komponenten wieQ ₁ undT ₂ Karten der Linien gleicher Amplitude und Phase gezeichnet werden können. FürS ₁ wird ebenfalls eine solche Karte dargestellt. Das Vorhandensein dieser Komponente ist nicht auf die Gezeitenkräfte zurückzuführen, sondern auf Unregelmäßigkeiten in der Gestalt der Erde oder in der Verteilung ihrer Masse. Effekte dritter Ordnung in einer Größe von 1 bis 9 mm sind offensichtlich in halbtägigen Gezeiten enthalten. Sie übersteigen sogar die der zweiten Ordnung an einigen Stationen. Das Vorhandensein von Verbundtiden nichtlinearen Ursprungs wie2MK ₂ ,MOK ₂ undNK ₃ ist ebenfalls erkennbar.

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Propos sur les très petites constantes harmoniques perceptibles dans les marées du Pacifique

Résumé Plus de 85% des composantes de la marée, le long de la côte occidentale du Mexique, ont une amplitude qui n'excède pas 2 cm. Néanmoins, elles émergent clairement du bruit de fond, ce qui permet même d'en tracer des cartes cotidales, soient celles deQ ₁ ouT ₂ par exemple. Nous présentons aussi une telle carte pourS ₁ : nous attribuons son existence non à la force de marée, mais plutôt à quelque déformité dans la géoide ou dans la distribution de sa masse. Des effets de troisième ordre, de 1 à 9 mm d'envergure, sont manifestes dans la bande semidiurne; en fait ils dépassent la contribution du deuxième ordre en certains endroits. Des composantes d'origine non linéaire, comme2MK ₂ ,MOK ₂ etNK ₃ , se descernent aussi.

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The response of mercury (Hg) transformation in soil to sulfur compounds and sulfur-rich biowaste application     

Jiřina Száková  Andrea Burešová  Lukáš Praus  Mercedes García-Sánchez  Zlata Holečková  Jiří Gabriel  Jiřina Sysalová  Rostislav Červenka  Josef Komárek  Slávka Grohová  Pavel Tlustoš 《Environmental Earth Sciences》2016,75(7):584

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Using a regional frequency analysis approach for calculating the Standardized Precipitation Index: an operational approach based on the two-parameter gamma distribution     

dos Santos Junior  Edimar Pereira  Xavier  Ana Carolina Freitas  Martins  Letícia Lopes  da Rocha Sobierajski  Graciela  Blain  Gabriel Constantino 《Theoretical and Applied Climatology》2022,148(3-4):1199-1216

Theoretical and Applied Climatology - The Standardized Precipitation Index (SPI) is a worldwide used probability-based drought index. Considering that the two-parameter gamma distribution (gam) is...  相似文献   

ONE- and TWO-Equation Models for Canopy Turbulence   总被引：2，自引：17，他引：2  

Gabriel G. Katul  Larry Mahrt  Davide Poggi  Christophe Sanz 《Boundary-Layer Meteorology》2004,113(1):81-109

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A model for sensible heat flux probability density function for near-neutral and slightly-stable atmospheric flows   总被引：2，自引：0，他引：2  

Gabriel G. Katul 《Boundary-Layer Meteorology》1994,71(1-2):1-20

The probability density function for sensible heat flux was measured above a uniform dry lakebed (Owens lake) in Owens Valley, California. It was found that for moderately stable to near neutral atmospheric stability conditions, the probability density function exhibits well defined exponential tails. These exponential tails are consistent with many laboratory boundarylayer measurements and numerical simulations. A model for the sensible heat flux probability density function was developed and tested. A key assumption in the model derivation was the near Gaussian statistics of the vertical velocity and temperature fluctuations. This assumption was verified from time series measurements of temperature and vertical velocity. The parameters for the sensible heat flux probability density function model were also derived from mean meteorological and surface conditions using surface-layer similarity theory. It was found that the best agreement between modeled and measured sensible heat flux probability density function was at the tails. Finally, a relation between the intermittency parameter, the probability density function, and the mean meteorological conditions was derived. This relation rigorously links the intermittency parameter to mean meteorological conditions.  相似文献   

An investigation of the phenomenon of double high water or double low water at some harbours     

Dr. Gabriel Godin 《Ocean Dynamics》1993,45(2):87-106

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Hydro-geomechanical characterisation of a coastal urban aquifer using multiscalar time and frequency domain groundwater-level responses     

Patton  Ashley M.  Rau  Gabriel C.  Cleall  Peter J.  Cuthbert  Mark O. 《Hydrogeology Journal》2021,29(8):2751-2771

Hydraulic properties of coastal, urban aquifers vary spatially and temporally with the complex dynamics of their hydrogeology and the heterogeneity of ocean-influenced hydraulic processes. Traditional aquifer characterisation methods are expensive, time-consuming and represent a snapshot in time. Tidal subsurface analysis (TSA) can passively characterise subsurface processes and establish hydro-geomechanical properties from groundwater head time-series but is typically applied to individual wells inland. Presented here, TSA is applied to a network of 116 groundwater boreholes to spatially characterise confinement and specific storage across a coastal aquifer at city-scale in Cardiff (UK) using a 23-year high-frequency time-series dataset. The dataset comprises Earth, atmospheric and oceanic signals, with the analysis conducted in the time domain, by calculating barometric response functions (BRFs), and in the frequency domain (TSA). By examining the damping and attenuation of groundwater response to ocean tides (OT) with distance from the coast/rivers, a multi-borehole comparison of TSA with BRF shows this combination of analyses facilitates disentangling the influence of tidal signals and estimation of spatially distributed aquifer properties for non-OT-influenced boreholes. The time-series analysed covers a period pre- and post-impoundment of Cardiff’s rivers by a barrage, revealing the consequent reduction in subsurface OT signal propagation post-construction. The results indicate that a much higher degree of confined conditions exist across the aquifer than previously thought (specific storage?=?2.3 × 10^?6 to 7.9 × 10^?5 m^?1), with implications for understanding aquifer recharge, and informing the best strategies for utilising groundwater and shallow geothermal resources.

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Biodegradation of p‐Chloroaniline and Ammonium Removal in Continuous Biofilm Reactors          下载免费PDF全文

Ana J. González  Lina X. Celis Bautista  Mariana Papalia  Marcela Radice  Gabriel Gutkind  Anahí Magdaleno  Estela I. Planes  Gustavo D. Bulus Rossini  Alfredo Gallego  Sonia E. Korol 《洁净——土壤、空气、水》2014,42(4):449-455

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Hydro‐morphologic Revision of the Cuautla Channel at Nayarit,Mexico     

Cuauhtemoc Franco Ochoa  Edgar Mendoza Baldwin  Rodolfo Silva Casarín  Gabriel Ruiz Martínez 《洁净——土壤、空气、水》2012,40(9):920-925

Pollution, habitat modification, and species migration are some of the results of human activities on natural environments which can be mitigated or compensated with proper planning. Irresponsibility or ignorance in planning coastal projects too often produces damage to natural systems which can be unpredictable and sometimes irrevocable. The specific site analyzed in this paper is the Cuautla littoral sub‐system which was originally a lagoon that diverted river water to other lagoons and estuaries, thus irrigating the Mexican Marismas Nacionales system, in the states of Nayarit and Sinaloa, Mexico. In the 1970s social and economic considerations motivated the construction of a small breaching canal from the sea to the lagoon. The subsequent growth of this channel was unforeseen and has produced an irreversible impact not only in the sub‐system but probably in the entire area of Marismas Nacionales. A lack of understanding of the present balances in the damaged system and of the impacts the changing morphology has on future change has created the need to study this area using numerical hydrodynamic simulation. The present distribution of water in the sub‐system was established and the governing processes were detected. By means of an analytical estimation of equilibrium conditions it was found that if nothing is done, the channel will continue eroding and the ecosystem will continue to degrade. Only by understanding the dramatic perturbations caused by the construction of the channel to the hydrologic and morphologic equilibriums can there be any hope of rescuing the ecosystem, including its human activities.  相似文献