Global warming and rainfall oscillation in the 5–10 yr band in Western Europe and Eastern North America     

Jean-Louis Pinault 《Climatic change》2012,114(3-4):621-650

From joint wavelet analysis of long-wavelength baroclinic Rossby waves and SST anomalies in the 5–10?yr band in the North and tropical Atlantic, and Reduced Rainfall Height (RRH) in Western Europe and Eastern North America, some key mechanisms involved in the interannual rainfall variability are highlighted. Systematic work has been undertaken to highlight the resonance of long planetary waves in the tropical oceans. Quasi-stationary Waves (QSWs) are produced resulting from the combination of gravitational forces and trade wind stress or ENSO events to compensate for energy lost in the resonator and, above all, to produce a strong modulated output current at the open end, contributing to the western boundary currents. Gravitational forces are resulting from the topography of the surface of the ocean at the antinodes, the dimension of the basin and the wavelength of planetary waves involved in the resonance being of the same order of magnitude. Remote resonances occur at critical latitudes, nearly 40°N and 40°S, forming QSWs the role of which is crucial in the functioning of sub-tropical gyres. In the North Atlantic subtropical gyre, an 8-yr period QSW appears to have a decisive role in the interannual rainfall variability. The pattern of SST anomalies depends on buoyancy of the advected layer associated with this QSW, which is controlled by the amplitude and the phase of long-period sub-harmonics. Rainfall oscillation in Western Europe has occurred for some decades and extended as the dipole formed by SST anomalies on both antinodes became unbalanced, due to the emergence of the advected layer further north. Since then cyclonic or anticyclonic conditions are prevailing at midlatitudes, depending on the polarity. Strengthening of RRH anomalies in Eastern North America is attributed to the buoyancy of the advected layer that re-circulates along the sub-tropical gyre, which evidences the excitation of long-period sub-harmonics, too. Frequency of exceptional events increased in areas heavily exposed to RRH anomalies, subject to oceanic influences even during extreme events, as this occurs in the north of France. Changes in rainfall patterns is attributed to global warming, i.e. the resonance of long-period sub-harmonics associated with solar magnetic cycles whose amplitude has increased drastically at the end of the second millennium, not including the possible contribution of greenhouse gas emissions whose impact on climate is non-resonant.  相似文献   

Relationships between cut-off lows and the semiannual and southern oscillations     

Alice Favre  Bruce Hewitson  Mark Tadross  Christopher Lennard  Ruth Cerezo-Mota 《Climate Dynamics》2012,38(7-8):1473-1487

The characteristics of Southern Cut-off Lows (CoLs) are studied for the period 1979–2008. The systematic identification of CoLs is realized by applying an original automated scheme using mean daily geopotential height and air temperature at 500?hPa NCEP-DOE II Reanalysis data. From closed lows’ trajectories established from the Equator to the polar jet stream, extratropical lows are analyzed and the stage of cut-off is defined as a secluded low presenting a cold core. From 4,843 cases the general CoL features are presented and confirm several previous results such as the geographic distribution which shows that they are more frequent in the latitudinal band contained between 20°S and 45°S and in close proximity to the continents. On a seasonal time scale, CoLs are more numerous from late summer to autumn, with a maximum of frequency in March/April. In winter (June–July–August), they are fewer but deeper than during the rest of the year. In the median domain (~32.5°S), the annual cycle of the frequency is bimodal and present two peaks during transitional seasons. In this zone, the seasonal cycle varies in accordance with the Semiannual Oscillation. Thereby, when the meridional gradient of temperature/pressure is reinforced between mid and high latitudes, CoLs are more frequent in the median domain. Over the period 1979–2008, the annual CoLs’ frequency exhibits a positive trend of about 25%. This increase is associated with a widening of the latitudinal domain of occurrence equatorward as well as poleward. The trend is linked with an abrupt positive shift in the number of CoLs’ generation between 1998 and 1999. The geographical distribution of CoLs frequency varies significantly in accordance with El Ni?o Southern Oscillation with more CoL’s at lower (higher) latitudes during La Ni?a (El Ni?o) events, principally in the Southern Pacific.  相似文献   

Metal speciation in fluid inclusions using microbeam X-ray absorption spectroscopy     

Julianne James-Smith  Joël Brugger  Jean Cauzid  Denis Testemale  Jean-Louis Hazemann  Weihua Liu  Olivier Proux 《Journal of Geochemical Exploration》2009

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Geological structure, recharge processes and underground drainage of a glacierised karst aquifer system, Tsanfleuron-Sanetsch, Swiss Alps   总被引：1，自引：1，他引：0  

Vivian Gremaud  Nico Goldscheider  Ludovic Savoy  Gérald Favre  Henri Masson 《Hydrogeology Journal》2009,17(8):1833-1848

The relationships between stratigraphic and tectonic setting, recharge processes and underground drainage of the glacierised karst aquifer system ‘Tsanfleuron-Sanetsch’ in the Swiss Alps have been studied by means of various methods, particularly tracer tests (19 injections). The area belongs to the Helvetic nappes and consists of Jurassic to Palaeogene sedimentary rocks. Strata are folded and form a regional anticlinorium. Cretaceous Urgonian limestone constitutes the main karst aquifer, overlain by a retreating glacier in its upper part. Polished limestone surfaces are exposed between the glacier front and the end moraine of 1855/1860 (Little Ice Age); typical alpine karrenfields can be observed further below. Results show that (1) large parts of the area are drained by the Glarey spring, which is used as a drinking water source, while marginal parts belong to the catchments of other springs; (2) groundwater flow towards the Glarey spring occurs in the main aquifer, parallel to stratification, while flow towards another spring crosses the entire stratigraphic sequence, consisting of about 800 m of marl and limestone, along deep faults that were probably enlarged by mass movements; (3) the variability of glacial meltwater production influences the shape of the tracer breakthrough curves and, consequently, flow and transport in the aquifer.  相似文献   

Two-stage partial melting during the Variscan extensional tectonics (Montagne Noire,France)     

Poujol  Marc  Pitra  Pavel  Van Den Driessche  Jean  Tartèse  Romain  Ruffet  Gilles  Paquette  Jean-Louis  Poilvet  Jean-Charles 《International Journal of Earth Sciences》2017,106(2):477-500

International Journal of Earth Sciences - One of the striking features that characterise the late stages of the Variscan orogeny is the development of gneiss and migmatite domes, as well as...  相似文献   

Which are the dwarfs in the Solar System?     

Gonzalo Tancredi  Sofía Favre 《Icarus》2008,195(2):851-862

The International Astronomical Union recently adopted a new definition of planets in our Solar System. A new category of objects was introduced: a “dwarf planet.” This is “a celestial body that has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape and has not cleared the neighborhood around its orbit.” In a footnote, the resolution says: “An IAU process will be established to assign borderline objects into either “dwarf planet” and other categories." In order to contribute to the establishment of this classification procedure, we analyze the problem of the minimum mass required to become a “dwarf planet,” either from the theoretical and the observational perspective. We propose classification criteria for “dwarf planets” based on the available information on the shape and size of asteroids and TNOs, principally the direct or indirect estimates of the diameter and the estimate of the shapes from the lightcurves. We compile the available observational data on large asteroids and TNOs. According to our classification scheme there is only one rocky “dwarf planet” and 12 icy “dwarf planets” among the already discovered objects.  相似文献   

Addressing ore formation and exploration     

Jean-Louis Vigneresse 《地学前缘(英文版)》2019,10(4):1613-1622

Common base and noble metals represent an important economic factor in the actual industrial development.For instance the world resources for copper are actually estimated for about the next 30 years only.The situation requires rethinking the way major ore deposits form,leading to new guides for exploration.The present paper briefly examines the processes leading to ore formation,in relation with granitic or granodioritic intrusions.It identifies the importance of metal enrichment during the magmatic stage.Within the magma chamber that forms porphyry intrusions,metals may incorporate to first formed crystals,becoming inert;concentrate into the residual melt of a mush;or segregate by diffusion into the exsolved magmatic volatile phase(MVP)into which they are transported and precipitated.A competition results between elements partitioning and diffusivity.Hence,a specific Peclet number for each metal(Cu,Au,Ag,Mo,W,Sn,and REE)controls the ratio between the diffusive and the advective flux.Metals diffusivity in the melt shows differential behavior relative to a threshold of about10 13 m2/s.Metals with slower diffusivity values(e.g.As)will not concentrate.Conversely,fast diffusive metals(Au,Ag,Cu)may rapidly incorporate the MVP,provided an adequate component(halogens or S)is attractive for metals.The chemistry of the MVP escaping the magma induces different alteration patterns.Their relative content in F,Cl or S,attested by the composition of biotites and apatites,links with the preferential content of metals in o re deposits,representing a valuable tool for exploration.Finally the model is replaced in a set of coupled mechanical-chemical instabilities,within a three phase material.  相似文献   

Modeling of cadmium speciation and dynamics in the Seine estuary (France)     

Jean-Louis Gonzalez  Benedicte Thouvenin  Catherine Dange  Annie Fiandrino  Jean-François Chiffoleau 《Estuaries and Coasts》2001,24(6):1041-1055

A complexation model (MOCO) was used to describe cadmium (Cd) speciation during estuarine transit in the Seine estuary. This model was developed from field data. Laboratory experiments based on the use of¹⁰⁹Cd enabled checking of certain model simplifications and hypotheses and evaluation of parameters which could not be measured directly. MOCO was coupled with a 3D multivariable hydrosedimentary model (SAM3D) to simulate Cd dynamics in the estuary. These results were compared with measurements (dissolved and particulate Cd) obtained during cruises representative of various hydrodynamic conditions. The purpose of this article is to present the modeling approach used, and its expected applications and limits.  相似文献   

Geometric Measurement Analysis Versus Fourier Series Analysis for Shape Characterization Using the Gastropod Shell ( Trivia ) as an Example     

Elisabeth Dommergues  Jean-Louis Dommergues  Françoise Magniez  Pascal Neige  Eric P. Verrecchia 《Mathematical Geology》2003,35(7):887-894

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The level of pollution of Kerguelen islands biota by organochlorine compounds during the seventies     

Jean-Louis Monod  Patrick M. Arnaud  Andr  Arnoux 《Marine pollution bulletin》1992,24(12):626-629

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