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Dominique AubertPeter Stille Anne ProbstFrançois Gauthier-lafaye Laurent PourcelotMireille Del nero 《Geochimica et cosmochimica acta》2002,66(19):3339-3350
Rainwater and snow collected from three different sites in France (Vosges Mountains, French Alps and Strasbourg) show more or less similar shapes of their REE distribution patterns. Rainwater from Strasbourg is the most REE enriched sample, whereas precipitations from the two mountainous, less polluted catchments are less REE enriched and have concentrations close to seawater. They are all strongly LREE depleted.Different water samples from an Alpine watershed comprising snow, interstitial, puddle and streamwater show similar REE distributions with LREE enrichment (rainwater normalized) but MREE and HREE depletion. In this environment, where water transfer from the soil to the river is very quick due to the low thickness of the soils, it appears that REE in streamwater mainly originate from atmospheric inputs. Different is the behaviour of the REE in the spring- and streamwaters from the Vosges Mountains. These waters of long residence time in the deep soil horizons react with soil and bedrock REE carrying minerals and show especially significant negative Eu anomalies compared to atmospheric inputs. Their Sr and Nd isotopic data suggest that most of the Sr and Nd originate from apatite leaching or dissolution. Soil solutions and soil leachates from the upper soil horizons due to alteration processes strongly depleted in REE carrying minerals, have REE distribution patterns close to those of lichens and throughfall. Throughfall is slightly more enriched especially in light REE than filtered rainwater probably due to leaching of atmospheric particles deposited on the foliage and also to leaf excretion.Data suggest that Sr and Nd isotopes of the soil solutions in the upper soil horizons originate from two different sources: 1) An atmospheric source with fertilizer, dust and seawater components and 2) A source mainly determined by mineral dissolution in the soil. These two different sources are also recognizable in the Sr and Nd isotopic composition of the tree’s throughfall solution. The atmospheric contributions of Sr and Nd to throughfall and soil solution are of 20 to 70 and 20%, respectively. In springwater, however, the atmospheric Sr and REE contribution is not detectable. 相似文献
44.
Milena B. Fernandes Marie-Alexandrine Sicre Anne Boireau Jacek Tronczynski 《Estuaries and Coasts》1997,20(2):281-290
Dissolved and particulate hydrocarbons of biogenic origin were investigated for the first time in surface waters along the Seine River and its estuary. They comprise n-alkanes (n-ALKs) and diagenetic polycyclic aromatic hydrocarbons (PAHs). Samples were collected in three different sections of the estuary: the riverine zone, the mixing zone, and the marine zone. At the river mouth, two mooring stations were used for the collection of samples over tidal cycles. Total particulate n-ALK concentrations ranged from 31 ng 1?1 to 2,918 ng 1?1, or 5 μg g?1 dry ng 1?1, or 2 μg g?1 of SM. Concentrations varied with the SM load and could be related to sedimentation and estuarine mixing. The sources of the n-ALKs were different in each zone of the estuary. The dissolved n-ALKs displayed lower concentrations than the particulate phase, varying from 136 ng 1?1 to 344 ng 1?1, while biogenic dissolved PAHs were almost absent. 相似文献
45.
This work proposes a complete method for automatic inversion of data from hydraulic interference pumping tests based on both homogeneous and fractal dual-medium approaches. The aim is to seek a new alternative concept able to interpret field data, identify macroscopic hydraulic parameters and therefore enhance the understanding of flow in porous fractured reservoirs. Because of its much contrasted sensitivities to parameters, the dual-medium approach yields an ill-posed inverse problem that requires a specific optimization procedure including the calculation of analytical sensitivities and their possible re-scaling. Once these constraints are fulfilled, the inversion proves accurate, provides unambiguous and reliable results. In the fractal context inverting several drawdown curves from different locations at the same time reveals more accurate. Finally, hydraulic parameters drawn from inversion should be taken into account to improve in various situations the conditioning of up-scaled flow in fractured rocks. 相似文献
46.
Martin Füllekrug Declan Diver Jean-Louis Pinçon Alan D. R. Phelps Anne Bourdon Christiane Helling Elisabeth Blanc Farideh Honary R. Giles Harrison Jean-André Sauvaud Jean-Baptiste Renard Mark Lester Michael Rycroft Mike Kosch Richard B. Horne Serge Soula Stéphane Gaffet 《Surveys in Geophysics》2013,34(1):1-41
The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth’s atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth’s atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth’s atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized. 相似文献
47.
In 2001, the National Oceanic and Atmospheric Administration (NOAA) and the Ministry of Maritime Affairs and Fisheries Integrated Coastal and Ocean Resources Scientific and Technical Arrangement was signed to pursue scientific and technical cooperation in integrated coastal and ocean resources management in the mutual interest of the participants. Over the last 6 years, the cooperation has been very beneficial, particularly for advancing marine science and management programs in Korea, such as Deep Sea Aquaculture, Sea Grant College Program, Marine Protected Areas, and Ocean Observations. The benefits to NOAA from the cooperation include Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, ocean and coastal observations, GEOSS program, and Global Program of Action. Also the cooperation has spillover effects on other ocean science and technological arrangement between US and Korea. This article reviews purpose, obstacles, and achievement of the cooperation and suggests recommendations for the future steps. 相似文献
48.
The Livelihood Vulnerability Index: A pragmatic approach to assessing risks from climate variability and change—A case study in Mozambique 总被引:3,自引:0,他引:3
We developed the Livelihood Vulnerability Index (LVI) to estimate climate change vulnerability in the Mabote and Moma Districts of Mozambique. We surveyed 200 households in each district to collect data on socio-demographics, livelihoods, social networks, health, food and water security, natural disasters and climate variability. Data were aggregated using a composite index and differential vulnerabilities were compared. Results suggest that Moma may be more vulnerable in terms of water resources while Mabote may be more vulnerable in terms of socio-demographic structure. This pragmatic approach may be used to monitor vulnerability, program resources for assistance, and/or evaluate potential program/policy effectiveness in data-scarce regions by introducing scenarios into the LVI model for baseline comparison. 相似文献
49.
Anne M. Larson Maria Brockhaus William D. Sunderlin Amy Duchelle Andrea Babon Therese Dokken Thu Thuy Pham I.A.P. Resosudarmo Galia Selaya Abdon Awono Thu-Ba Huynh 《Global Environmental Change》2013,23(3):678-689
A number of international donors, national governments and project proponents have begun to lay the groundwork for REDD+, but tenure insecurity – including the potential risks of land grabbing by outsiders and loss of local user rights to forests and forest land – is one of the main reasons that many indigenous and other local peoples have publicly opposed it. Under what conditions is REDD+ a threat to local rights, and under what conditions does it present an opportunity? This article explores these issues based on available data from a global comparative study on REDD+, led by the Center for International Forestry Research, which is studying national policies and processes in 12 countries and 23 REDD+ projects in 6 countries. The article analyses how tenure concerns are being addressed at both national and project level in emerging REDD+ programs. The findings suggest that in most cases REDD+ has clearly provided some new opportunities for securing local tenure rights, but that piecemeal interventions by project proponents at the local level are insufficient in the absence of broader, national programs for land tenure reform. The potential for substantial changes in the status quo appear unlikely, though Brazil – the only one with such a national land tenure reform program – offers useful insights. Land tenure reform – the recognition of customary rights in particular – and a serious commitment to REDD+ both challenge the deep-rooted economic and political interests of ‘business as usual’. 相似文献
50.
Anne W. Nolin Eric A. Sproles David E. Rupp Ryan L. Crumley Mariana J. Webb Ross T. Palomaki Eugene Mar 《水文研究》2021,35(6):e14262
Snow is Earth's most climatically sensitive land cover type. Traditional snow metrics may not be able to adequately capture the changing nature of snow cover. For example, April 1 snow water equivalent (SWE) has been an effective index for streamflow forecasting, but it cannot express the effects of midwinter melt events, now expected in warming snow climates, nor can we assume that station-based measurements will be representative of snow conditions in future decades. Remote sensing and climate model data provide capacity for a suite of multi-use snow metrics from local to global scales. Such indicators need to be simple enough to “tell the story” of snowpack changes over space and time, but not overly simplistic or overly complicated in their interpretation. We describe a suite of spatially explicit, multi-temporal snow metrics based on global satellite data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and downscaled climate model output for the U.S. We describe and provide examples for Snow Cover Frequency (SCF), Snow Disappearance Date (SDD), At-Risk Snow (ARS), and Frequency of a Warm Winter (FWW). Using these retrospective and prospective snow metrics, we assess the current and future snow-related conditions in three hydroclimatically different U.S. watersheds: the Truckee, Colorado Headwaters, and Upper Connecticut. In the two western U.S. watersheds, SCF and SDD show greater sensitivity to annual differences in snow cover compared with data from the ground-based Snow Telemetry (SNOTEL) network. The eastern U.S. watershed does not have a ground-based network of data, so these MODIS-derived metrics provide uniquely valuable snow information. The ARS and FWW metrics show that the Truckee Watershed is highly vulnerable to conversion from snowfall to rainfall (ARS) and midwinter melt events (FWW) throughout the seasonal snow zone. In comparison, the Colorado Headwaters and Upper Connecticut Watersheds are colder and much less vulnerable through mid- and late-century. 相似文献