The Amoco Cadiz oil spill—Lines of study and early observations     

Lucien Laubier 《Marine pollution bulletin》1978,9(11):285-287

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Ground‐based thermal imagery as a simple,practical tool for mapping saturated area connectivity and dynamics     

Laurent Pfister  Jeffrey J. McDonnell  Christophe Hissler  Lucien Hoffmann 《水文研究》2010,24(21):3123-3132

The hillslope‐riparian‐stream system is a key functional unit of catchments, yet very difficult to measure and monitor due to its tremendous complexity and high spatio‐temporal variability. Here, we present a simple and practical tool for imaging directly these hillslope‐riparian‐area connections. We used a FLIR b50 infrared camera to produce thermal images at the scale of 140 × 140 pixels over the spectral range 7·5–13 µm. Our IR imaging technique is sensitive to the upper 0·1 mm of the water column. Images were obtained from a constant position on the right bank of the Weierbach catchment in Luxembourg, at an incidence angle of approximately 45° over a 5‐week period. The study site measured 5 × 3 m. Our results show that ground‐based IR imagery can discriminate between areas with snow cover, snow melt, soil seepage, and stream water. More importantly, it can detect when and where variably saturated areas are active and when connectivity exists between the hillslope–riparian–stream system. Our proof of concept suggests that this is a simple, inexpensive technology for sequential mapping and characterisation of surface saturated areas and a useful complement to conventional tracer techniques. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Saturn's rings: Infrared brightness variation with solar elevation     

Lucien Froidevaux 《Icarus》1981,46(1):4-17

The variation in infrared equilibrium brightness temperature of Saturn's A, B, and C rings is modeled as a function of solar elevation B′ with respect to the ring plane. The basic model includes estimates of minimum and maximum interparticle shadowing in a monolayer approximation. Simple laboratory observations of random particle distributions at various illumination angles provide more realistic shadowing functions. Radiation balance calculations yield the physical (kinetic) temperature of particles in equilibrium with radiation from the Sun, Saturn, and neighboring particles. Infrared brightness temperatures as a function of B′ are then computed and compared to the available 20-μm data (Pioneer results are also briefly discussed). The A and B rings are well modeled by an optically thick monolayer, or equivalently, a flat sheet, radiating from one side only. This points to a temperature contrast between the two sides, possibly due to particles with low thermal inertia. Other existing models for the B ring are discussed. The good fit for the monolayer model does not rule out the possibility that the A and B rings are many particles thick. It could well be that a multilayer ring produces an infrared behavior (as a function of tilt angle) similar to that of a monolayer. The C ring brightness increases as B′ decreases. This contrast in behavior can be understood simply in terms of the low C ring optical depth and small amount of interparticle shadowing. High-albedo particles (A?0.5) can fit the C ring infrared data if they radiate mostly from one hemisphere due to slow rotation or low thermal inertia (or both). Alternatively, particles isothermal over their surface (owing to a rapid spin, high inertia, or small size), and significantly darker (A?0.3) than the A and B ring particles, can produce a similar brightness variation with ring inclination. In any case, the C ring particles have significantly hotter physical temperatures than the particles in the A and B rings, whether or not the rings form a monolayer.  相似文献   

Mining under a limestone aquifer in southern Sardinia: a multiobjective approach     

Marco Salis  Lucien Duckstein 《Geotechnical and Geological Engineering》1983,1(4):357-374

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Deep biological communities in the subduction zone of Japan from bottom photographs taken during “nautile” dives in the Kaiko project     

Suguru Ohta  Lucien Laubier 《Earth and Planetary Science Letters》1987,83(1-4)

Twenty-seven dives of the submersible “Nautile” in the subduction zone around Japan conducted in the French-Japanese Project Kaiko proved that fairly luxuriant benthic communities dominated by deep-sea giant clams of the genusCalyptogena (family Vesicomyidae) were consistently present on the accretionary prism at abyssal depths.Benthic communities characterized by three hitherto undescribed bivalves of the genusCalyptogena were found between depths of about 3800 and 4020 m at the mouth of Tenryu Canyon and at the top of basement swell of the Zenisu Ridge, both situated in the eastern Nankai subduction zone. Sporadic but discrete patches of organisms characterized by one more undescribed bivalve belonging to the genusCalyptogena were observed and collected between depths of 5130 and 5960 m on the landward wall of the Japan and Kouriles Trenches.Photographic inventories were prepared semiquantitatively using each series of bottom photographs taken in these areas with bow cameras of the submersible “Nautile”.Observations on the sporadic but dense distribution of the clams and other characteristic associated organisms match well with the scheme that communities sustained by chemosynthetic energy sources can be present at connate water seepages in subduction zones. These are to date the deepest record of benthic communities supposedly associated with chemosynthetic processes.  相似文献   

Atmospheric lee waves in the Aegean Sea and their possible influence on the sea surface     

Lucien Wald  Dimitri Georgopoulos 《Boundary-Layer Meteorology》1984,28(3-4):309-315

Unusual satellite images of the Aegean Sea, in both the visible and infrared ranges, are discussed. Alternating bright and dark features downwind of islands suggest the presence of atmospheric lee waves. However, close examination of these features indicates that the observed signal is likely the signature of the influence of the lee waves on the sea surface rather than the signature of the lee waves themselves through atmospheric effects.  相似文献   

Model selection in multiobjective decision making for river basin planning     

Lucien Duckstein  Mark Gershon  Richard McAniff 《Advances in water resources》1982,5(3):178-184

Appropriate model selection among three alternative multiobjective techniques is studied using an example in river basin planning. The three techniques are ELECTRE, compromise programming and multiattribute utility theory. Key questions in the selection process are concerned with the type of data required, the necessary amount of interaction between the decision maker and analyst, and the nature of the problem. Such characteristics are used as criteria to demonstrate whether or not a particular model can be successfully applied.  相似文献   

The rivers are alive: on the potential for diatoms as a tracer of water source and hydrological connectivity     

Laurent Pfister  Jeffrey J. McDonnell  Sebastian Wrede  Daša Hlúbiková  Patrick Matgen  Fabrizio Fenicia  Luc Ector  Lucien Hoffmann 《水文研究》2009,23(19):2841-2845

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A DUAL mission for nuclear astrophysics     

Peter von Ballmoos  Jose Alvarez  Nicolas Barrière  Steve Boggs  Andrei Bykov  Juan Manuel Del Cura Velayos  Filippo Frontera  Lorraine Hanlon  Margarita Hernanz  Emmanuel Hinglais  Jordi Isern  Pierre Jean  Jürgen Kn?dlseder  Lucien Kuiper  Mark Leising  Beno?t Pirard  Jean-Pierre Prost  Rui M. Curado da Silva  Tadayuki Takahashi  John Tomsick  Roland Walter  Andreas Zoglauer 《Experimental Astronomy》2012,34(2):583-622

DUAL will study the origin and evolution of the elements and explores new frontiers of physics: extreme energies that drive powerful stellar explosions and accelerate particles to macroscopic energies; extreme densities that modify the laws of physics around the most compact objects known; and extreme fields that influence matter in a way that is unknown on Earth. The variability of these extreme objects requires continuous all-sky coverage, while detailed study demands an improvement in sensitivity over previous technologies by at least an order of magnitude. The DUAL payload is composed of an All-Sky Compton Imager (ASCI), and two optical modules, the Laue-Lens Optic (LLO) and the Coded-Mask Optic (CMO). The ASCI serves dual roles simultaneously, both as an optimal focal-plane sensor for deep observations with the optical modules and as a sensitive true all-sky telescope in its own right for all-sky surveys and monitoring. While the optical modules are located on the main satellite, the All-Sky Compton Imager is situated on a deployable structure at a distance of 30?m from the satellite. This configuration not only permits to maintain the less massive payload at the focal distance, it also greatly reduces the spacecraft-induced detector background, and, above all it provides ASCI with a continuous all-sky exposure.  相似文献   

Pollution and eutrophication history AD 1800–2005 as recorded in sediments from five lakes in Central Chile     

Lucien von Gunten  Martin Grosjean  Urs Eggenberger  Philipp Grob  Roberto Urrutia  Arturo Morales 《Global and Planetary Change》2009,68(3):198-208

One of the fundamental problems to quantifying past impact of anthropogenic activities is that long series of observational data for pollutant deposition and changes in the nutrient cycling of ecosystems (eutrophication) are often not available. Lake sediments may provide suitable archives to decipher the history of local and regional pollution and eutrophication.Here we provide quantitative high-resolution data for the history of airborne pollutants and eutrophication from sediments of five lakes in Central Chile between ca. AD 1800–2005. We use spheroidal carbonaceous particles (SCPs) from fossil fuel combustion and excess atmospheric Cu deposition from mining activities as a proxy for atmospheric deposition. Organic carbon and nitrogen flux rates to the sediments and C/N ratios are used as a proxy for aquatic primary production and eutrophication.We show that the lake sediment SCP and Cu records are highly consistent and depict in great detail the local and regional history of urban, industrial and transportation history as reported in independent documentary sources and statistics. The pre-industrial and pre-1950 background concentrations (and flux rates) of the substances can be quantified. We can also show that technical measures taken in the early 1980s to trim down Cu emissions from the copper mines reduced the excess atmospheric Cu fallout to the lakes by about 50%.Eutrophication of the lakes did not start before ca. 1980. Prior to that time, warm season temperatures explain most of the variance in TOC and N flux to the sediments. The three dimictic lakes show only moderate eutrophication responses to enhanced N supply (as atmospheric fallout; enrichment factors for TOC and N 1.1–2.6), suggesting that mainly phosphorus controls aquatic primary production. The meromictic lake, where phosphorus recycling is likely, shows the largest response (enrichment factors for TOC and N between 9–20).While all five lakes show overall consistent and similar trends for the pollution history during the 19th and 20th century, there are significant differences in the details of the individual profiles. This suggests that local sources are highly important and the common regional (background) signal is relatively marginal. This is very different from Europe.  相似文献