Sensitivity analysis of a deterministic water temperature model to forest canopy and soil temperature in Catamaran Brook (New Brunswick,Canada)

A coupled deterministic hydrological and water temperature model, CEQUEAU, was modified to include soil temperature and crown closure in its calculation of local advective terms in the heat budget. The modified model was than tested to verify its sensitivity to these modifications. An analysis of the heat budget of a small forested catchment in eastern Canada revealed that the advective term related to interflow plays a significant role in the daily water heat budget, providing on average 28% of the local advective budget (which also includes advective heat terms from surface runoff and groundwater) and nearly 14% of the total heat budget (which includes all radiative terms at the water surface, convection and evaporation, as well as the local advective terms). Relative sensitivity indices (RSIs) were used to verify the impact of the newly introduced parameters and variables. Among them, parameters related to the forest cover (crown closure and leaf area index) have a maximum RSI of ?0·6; i.e. a 100% increase in value produces a 60% decrease in the local advective term. Parameters with the greatest influence are the volume of water contributing to interflow and the amplitude of the net radiative flux at the soil surface, which, if doubled, would double the contribution of the local interflow advective term to the heat budget. Copyright © 2003 John Wiley & Sons, Ltd.     

Realisation of a celestial system based on VLBI geodynamics programs

The relative orientations of various VLBI celestial reference frames are evaluated on the basis of coordinate differences of common sources. It is shown that an accuracy better than 0.001 can be achieved. Possible regional deformations in the different catalogues are investigated; they are found to reach a few 0.001 in some restricted zones. The application of these studies to the realisation of a combined celestial reference frame consistent with the BIH Terrestrial System is outlined.     

La marge continentale au large de l'estérel (France) et les mouvements verticaux pliocènes

Sommaire La région étudiée s'étend au large du massif des Maures, du massif de l'Estérel, des chaînes calcaires provençales et de la bordure alpine (Figure 1). Cette partie de la marge continentale médíterranéenne a été étudiée dans l'optique de la géodynamique en appliquant un ensemble de méthodes géophysiques, géologiques, sédimentologiques et géochimiques.La Méditerranée est l'objet de nombreuses études générales et son histoire tectonique est encore très discutée. Les relations entre la zone centrale (zone A) et les massifs terrestres géologiquement bien connus peuvent aider à la compréhension du cadre structural. L'étude très détaillée présentée ici concerne la marge continentale au large de la Côte d'Azur. Une étude bathymétrique préliminaire avec des profils espacés d'un mille marin a permis de définir un plateau continental peu étendu, une pente continentale abrupte (10–20°) avec des blocs continentaux effondrés. De nombreux canyons empruntent des accidents anciens qui ont rejoué.Des profils en série de sismique continue (Sparker et air gun) ont permis de délimiter la zone A qui comporte de nombreux dômes, de suivre des accidents majeurs, et de montrer des phénomènes sédimentaires et de néotectonique très importants (glissements, effondrements). Ces profils ont été calés avec 50 carottages. Un effondrement de plus de 1000 m depuis le Pliocène a été mis en évidence.La structure profonde a été abordée avec une étude de magnétométrie marine. La synthèse des résultats de sismique réfraction, de gravimétrie et de magnétométrie fait apparître un bombement du manteau sous la zone A avec abaissement rapide de la discontinuité de Moho sous la marge, la présence de volcans enfouis au Sud d'Antibes et de grands accidents de direction NS et EW.L'intérêt de ces résultats a semblé suffisamment important pour qu'un point de cette zone soit proposé pour le programme de forage JOIDES en Méditerranée.

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This paper deals with the region off the Maures and Estérel Massifs, the Provence calcareous ranges and the Alpine border (Figure 1). This portion of the Mediterranean continental margin has been investigated with the classical methods used in the geosciences: geophysics, geology, sedimentology, geochemistry.Many general studies are dealing with the Mediterranean and its tectonical history is still controversial. The relationship between the central zone (zone A) and the geologically well-known land massifs could help in understanding the structural framework. The present detailed study concerns the continental margin off Côte d'Azur. A relatively narrow continental shelf, a steep continental slope (10–20°) with collapsed continental blocks are defined by preliminary bathymetric studies with a spacing of one nautical mile. Many submarine canyons follow former faults which have been rejuvenated.A series of seismic reflection profiles (sparker and air-gun) provide limits for zone A (with many domes), allow tracing major faults and display important sedimentary and neotectonic processes (sliding, foundering). These profiles have been scaled with 50 cores. Evidence is brought forward for a local subsidence of over 1000 m. The deep structure has been investigated with marine magnetic methods. The results from seismic refraction, gravity and magnetics show a swell of the mantle beneath zone A, with a steep dipping of the M discontinuity under the margin, buried volcanoes south of Antibes and great faults striking NS or EW.These results seem to be important enough to propose a place in this zone of the Mediterranean as a JOIDES drilling site.

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Maintenant au Centre Océanologique de Bretagne, B.P. 337, 29 Brest, France.     

Applications géodésiques du système DORIS à l'Institut géographique national

IGN is in charge of the installation and maintenance of the DORIS orbit determination network. More recently, in collaboration with JPL, precise geodetic computations were performed. The goal of this paper is to recall the various historic contributions of IGN to the DORIS system in their international context and then to describe a new estimation technique developed for a multi-satellite mode, making full profit of a better modeling for satellites and ground clocks as well as tropospheric correction parameters. Derived geodetic results demonstrate a precision in the order of 1 cm for station positions. To cite this article: P. Willis et al., C. R. Geoscience 337 (2005).     

A Compilation of Silicon,Rare Earth Element and Twenty‐One other Trace Element Concentrations in the Natural River Water Reference Material SLRS‐5 (NRC‐CNRC)

The natural river water certified reference material SLRS‐5 (NRC‐CNRC) was routinely analysed in this study for major and trace elements by ten French laboratories. Most of the measurements were made using ICP‐MS. Because no certified values are assigned by NRC‐CNRC for silicon and 35 trace element concentrations (rare earth elements, Ag, B, Bi, Cs, Ga, Ge, Li, Nb, P, Rb, Rh, Re, S, Sc, Sn, Th, Ti, Tl, W, Y and Zr), or for isotopic ratios, we provide a compilation of the concentrations and related uncertainties obtained by the participating laboratories. Strontium isotopic ratios are also given.     

底栖生物生产力现场测试系统(BCSPM)的建立及其初步实验结果

为对生态系统的健康评估及底栖生物资源的开发利用提供技术支撑,在胶州湾筏式养殖水域,建立了底栖生物生产力现场测试系统(BCSPM),并在光照和黑暗条件下测定了沉积物海水界面溶解氧随时间的变化、计算了氧通量、估算了底栖总初级生产力和群落呼吸。在光照较强的中午时刻测定的群落总生产力为20．76mgCm^-2h^-1;养殖水域沉积物中的群落呼吸要高于邻近水域。BCSPM整体运转良好,初步结果为系统的改进和进一步实验提供了依据。     

On the inclusion of ground-based gravity measurements to the calibration process of a global rainfall-discharge reservoir model: case of the Durzon karst system (Larzac, southern France)

This work examines the relevance of the inclusion of ground-based gravity data in the calibration process of a global rainfall-discharge reservoir model. The analysis is performed for the Durzon karst system (Larzac, France). The first part of the study focuses on the hydrological interpretation of the ground-based gravity measurements. The second part of the study investigates further the information content of the gravity data with respect to water storage dynamics modelling. The gravity-derived information is found unable to either reduce equifinality of the single-objective, discharge-based model calibration process or enhance model performance through assimilation.     

Capture-zone design in an aquifer influenced by cyclic fluctuations in hydraulic gradients

Design of a groundwater pumping and treatment system for a wood-treatment facility adjacent to the tidally influenced Fraser River estuary required the development of methodologies to account for cyclic variations in hydraulic gradients. Design of such systems must consider the effects of these cyclic fluctuations on the capture of dissolved-phase contaminants. When the period of the cyclic fluctuation is much less than the travel time of the dissolved contaminant from the source to the discharge point, the hydraulic-gradient variations resulting from these cycles can be ignored. Capture zones are then designed based on the average hydraulic gradient determined using filter techniques on continuous groundwater-level measurements. When the period of cyclic fluctuation in hydraulic gradient is near to or greater than the contaminant travel time, the resulting hydraulic-gradient variations cannot be ignored. In these instances, procedures are developed to account for these fluctuations in the capture-zone design. These include proper characterization of the groundwater regime, assessment of the average travel time and period of the cyclic fluctuations, and numerical techniques which allow accounting for the cyclic fluctuations in the design of the capture zone. Electronic Publication     

Contribution of geophysical surveys to groundwater modelling of a porous aquifer in semiarid Niger: An overview

Subsurface geophysical surveys were carried out using a large range of methods in an unconfined sandstone aquifer in semiarid south-western Niger for improving both the conceptual model of water flow through the unsaturated zone and the parameterization of numerical a groundwater model of the aquifer. Methods included: electromagnetic mapping, electrical resistivity tomography (ERT), resistivity logging, time domain electromagnetic sounding (TDEM), and magnetic resonance sounding (MRS). Analyses of electrical conductivities, complemented by geochemical measurements, allowed us to identify preferential pathways for infiltration and drainage beneath gullies and alluvial fans. The mean water content estimated by MRS (13%) was used for computing the regional groundwater recharge from long-term change in the water table. The ranges in permeability and water content obtained with MRS allowed a reduction of the degree of freedom of aquifer parameters used in groundwater modelling.