A case study of the mesoscale dynamics in the North-Western Mediterranean Sea: a combined data–model approach     

Karen Guihou  Julien Marmain  Yann Ourmières  Anne Molcard  Bruno Zakardjian  Philippe Forget 《Ocean Dynamics》2013,63(7):793-808

The Northern current is the main circulation feature of the North-Western Mediterranean Sea. While the large-scale to mesoscale variability of the northern current (NC) is well known and widely documented for the Ligurian region, off Nice or along the Gulf of Lions shelf, few is known about the current instabilities and its associated mesoscale dynamics in the intermediate area, off Toulon. Here, we took advantage of an oceanographic cruise of opportunity, the start of a HF radar monitoring programme in the Toulon area and the availability of regular satellite sea surface temperature and chlorophyll a data, to evaluate the realism of a NEMO-based regional high-resolution model and the added value brought by HF radar. The combined analysis of a 1/64° configuration, named GLAZUR64, and of all data sets revealed the occurrence of an anticyclonic coastal trapped eddy, generated inside a NC meander and passing the Toulon area during the field campaign. We show that this anticyclonic eddy is advected downstream along the French Riviera up to the study region and disturbs the Northern current flow. This study aims to show the importance of combining observations and modelling when dealing with mesoscale processes, as well as the importance of high-resolution modelling.  相似文献   

Motif Discovery on Seismic Amplitude Time Series: The Case Study of Mt Etna 2011 Eruptive Activity     

Carmelo Cassisi  Marco Aliotta  Andrea Cannata  Placido Montalto  Domenico Patanè  Alfredo Pulvirenti  Letizia Spampinato 《Pure and Applied Geophysics》2013,170(4):529-545

Algorithms searching for similar patterns are widely used in seismology both when the waveforms of the events of interest are known and when there is no a priori-knowledge. Such methods usually make use of the cross-correlation coefficient as a measure of similarity; if there is no a-priori knowledge, they behave as brute-force searching algorithms. The disadvantage of these methods, preventing or limiting their application to very large datasets, is computational complexity. The Mueen–Keogh (MK) algorithm overcomes this limitation by means of two optimization techniques—the early abandoning concept and space indexing. Here, we apply the MK algorithm to amplitude time series retrieved from seismic signals recorded during episodic eruptive activity of Mt Etna in 2011. By adequately tuning the input to the MK algorithm we found eight motif groups characterized by distinct seismic amplitude trends, each related to a different phenomenon. In particular, we observed that earthquakes are accompanied by sharp increases and decreases in seismic amplitude whereas lava fountains are accompanied by slower changes. These results demonstrate that the MK algorithm, because of its particular features, may have wide applicability in seismology.  相似文献   

Reliable Procedure for Molecular Analysis of Airborne Microflora in Three Indoor Environments: An Office and Two Different Museum Contexts     

Carole Gaüzère  Marina Moletta‐Denat  Faisl Bousta  Stéphane Moularat  Geneviève Orial  Sébastien Ritoux  Jean‐Jacques Godon  Enric Robine 《洁净——土壤、空气、水》2013,41(3):226-234

Biological aerosols from air constitute a significant source of exposure to microorganisms in public places. Airborne microorganisms are involved in the development of certain respiratory symptoms, allergies, or infections among users and occupants. Various sampling instruments have commonly been used in aerobiology to collect bacteria and fungi suspended in the air. The objective of this study was to develop a reliable procedure for sampling in indoor public environments presenting different levels of occupancy, airborne bacteria and fungi to be subjected to molecular analysis (bacteria and fungi quantitative PCR, capillary electrophoresis single strand conformation polymorphism fingerprinting). Four different sampling devices were tested in situ in an office building (open‐plan type) and the sampling strategy chosen was tested in two museum contexts. In accordance with the drawbacks involved to our study (quantitative and qualitative aspects, cost, and overcrowding), cyclone device appeared to be most suitable. The results underline the effectiveness of this high‐volume aerosol sampling device for both qualitative and quantitative molecular analysis. Four in situ sampling collections were carried out in 1 day in the Louvre Museum to study quantitative and qualitative variations of airborne bacterial and fungal diversity. The quantitative results revealed a similar order of magnitude for the numbers of both bacteria and fungi. In the Louvre Museum, the samples yielded between 3.7 × 10⁴ and 4.1 × 10⁴ genome equivalent (GE) bacteria/m³ air and between 5.0 × 10⁴ and 5.9 × 10⁴ GE fungi/m³ air and in the Decorative Arts Museum between, 2.1 × 10⁴ and 2.5 × 10⁴ GE bacteria/m³ air and between 1.4 × 10⁴ and 1.7 × 10⁴ GE fungi/m³ air. The results also indicate that the dominant bacterial community displayed a stable structure over a short period of time whereas dominant eukaryotic airborne community appeared more variable.  相似文献   

Mastering the Niger. James MacQueen’s African Geography and the Struggle Over Atlantic Slavery     

Berny Sèbe 《The Cartographic journal》2013,50(1):91-92

Abstract

Since the publication of the first waterway map in 1990, the Inland Waterways of Britain series has expanded to a total of twenty three individual maps, a national route planning map, the first ring atlas and a directory of the inland waterways which explores aspects of preservation, restoration and heritage. Many of the titles have featured in walking guides, directories, promotional literature and web sites. This paper outlines the development of the series from the first map, describing the maps themselves, tracking the evolution of production methodologies, defining marketing and sales strategies and discussing the decision-making processes behind the publication and introduction of new titles.  相似文献   

Volcanic ash detection by GPS signal     

Massimo Aranzulla  Flavio Cannavò  Simona Scollo  Giuseppe Puglisi  Giuseppina Immè 《GPS Solutions》2013,17(4):485-497

We investigate the ability of GPS to detect volcanic plumes at Mt. Etna, Italy. We use a robust statistical approach to highlight whether the presence of a volcanic plume in the atmosphere may really affect the GPS undifferenced post-fit phase residuals. The proposed method has been tested for the September 4–5, 2007 activity of Mt. Etna. This eruption produced powerful lava fountains forming a weak, a few kilometers high plume for several hours, representing typical activity at Etna over the last 5 years. We analyzed data from nineteen Etna permanent GPS stations located on the volcano flanks at different heights and applied a statistical test based on four main steps: (a) realization of a simplified model representing the volcanic plume in atmosphere; (b) evaluation of the GPS satellite and station couples intersecting the plume; (c) calculation of the volcanic plume region crossed by the GPS signal; (d) application of a robust statistical test in order to see whether the volcanic plume affected the GPS signals. Results show that during the September 4–5, 2007 explosive activity, the GPS residuals definitely include the contribution of the volcanic plume. Our analysis shows that values of the GPS residuals are ten times smaller than those found for the Miyakejima eruption (Japan), highlighting a likely relationship between residuals and eruption intensity. In the future, data derived from the GPS stations located on Etna’s flanks could be used to improve the alerting system of volcanic ash, already operating at the Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo.  相似文献   

The sudden stratospheric warming and chemical ozone loss in the Antarctic winter 2019: comparison with the winters of 1988 and 2002     

Roy  R.  Kuttippurath  J.  Lefèvre  F.  Raj  S.  Kumar  P. 《Theoretical and Applied Climatology》2022,149(1-2):119-130

Theoretical and Applied Climatology - Sudden stratospheric warmings (SSWs) are associated with rapid rise in temperature in a short period of time in the polar vortex and reversal of the zonal...  相似文献   

It starts at home? Climate policies targeting household consumption and behavioral decisions are key to low-carbon futures     

Ghislain Dubois  Benjamin Sovacool  Carlo Aall  Maria Nilsson  Carine Barbier  Alina Herrmann  Sébastien Bruyère  Camilla Andersson  Bore Skold  Franck Nadaud  Florian Dorner  Karen Richardsen Moberg  Jean Paul Ceron  Helen Fischer  Dorothee Amelung  Marta Baltruszewicz  Jeremy Fischer  Françoise Benevise  Valérie R. Louis  Rainer Sauerborn 《Chemie der Erde / Geochemistry》2012

Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy.  相似文献   

The Hellenic ophiolites: eastward or westward obduction of the Maliac Ocean, a discussion   总被引：1，自引：0，他引：1  

Jacky Ferrière  Frank Chanier  Pitaksit Ditbanjong 《International Journal of Earth Sciences》2012,101(6):1559-1580

Ophiolitic bodies in the Dinaro-Hellenic mountain belt are among the most important ones in the Peri-Mediterranean Alpine chains. The characteristic feature of this ophiolitic belt is its Middle to Late Jurassic age of obduction. The ophiolitic bodies form two major belts on each side of the Pelagonian zone: an east Pelagonian belt in the Vardarian domain and a Supra-Pelagonian ophiolitic belt (SPO) to the west. The different hypotheses relative to the origin of the SPO present geodynamic evolution models accounting for most of the available data: a mid-Triassic episode of rifting; a Ladinian–Jurassic episode of sea-floor spreading forming notably the Maliac Ocean; a Middle to Late Jurassic convergent period with subduction and obduction episodes, and finally, a late episode of Tertiary compressional deformation responsible for the westward thrusting of the Jurassic ophiolitic nappes over the external zones. Despite many studies dating from the early 1970s, the eastern or western Pelagonian origin of these ophiolites, especially the SPO, is still under dispute. Whatever the adopted hypothesis, we consider that the main SPO bodies (N-Pindos, Vourinos, Othris, Evia, Argolis) have the same origin because of their geographic continuity and of the similarities in their geological characteristics. We propose that this ocean corresponds everywhere to the Maliac Ocean, defined in Othris from the well-preserved sedimentary (oceanic margin) and ophiolitic nappes thrust during the Late Jurassic obduction onto the Pelagonian platform. There is strong evidence for the existence of two deep basins on both sides of the Pelagonian continental ridge during Triassic–Jurassic times. They correspond, respectively, to the Vardar area to the east and the Pindos domain to the west, one of these domains being at the origin of the SPO. The hypothesis of an eastward emplacement of the SPO from the Pindos domain is based mainly on sedimentological data from the margin series and on structural analyses of ophiolitic bodies. However, we conclude the westward obduction of the Maliac Ocean, originating from the Vardar area, to be the best fitting model. This westward model is supported by paleogeographic and structural constraints on regional scale. Notably, the absence of obducted ophiolites in the Jurassic series of the Koziakas units (units attributed to the western Pelagonian margin) and of the Parnassus domain (on the eastern side of the Pindos basin) is difficult to reconcile with an eastward obduction from the Pindos domain. Other observations, such as the distribution of ophiolitic detritus in the internal and external zones, also promote the westward Late Jurassic obduction of the Maliac Ocean. Our preferred model offers a consistent explanation for the mechanism and timing of the emplacement of the SPO, as well as providing insight on the origin and emplacement of the Vardarian ophiolites. Following this hypothesis, there is no need for a clear boundary between the SPO and the west Vardarian ophiolitic bodies as they were obducted from the same oceanic basin and during the same Jurassic tectonic event. In this paper, we develop evidence in favor of the eastern Pelagonian origin for the SPO (our adopted model) and provide discussion on the data supporting the main alternative hypothesis (western origin for the SPO).  相似文献   

Dissolution of calcitic marble and dolomitic rock in high iron concentrated acid mine drainage: application to anoxic limestone drains     

Thomas Genty  Bruno Bussière  Robin Potvin  Mostafa Benzaazoua  Gérald J. Zagury 《Environmental Earth Sciences》2012,66(8):2387-2401

Oxidation of sulphide mining waste can generate acid mine drainage (AMD) that has the potential to seriously affect the ecosystems. Acid mine drainage is characterised by a high acidity, high concentrations of sulphates and metals. To reduce the environmental impacts due to AMD, neutralisation using limestone drains is an option proposed in the literature and used around the world. The present study focuses on the influence of the carbonate rock mineralogy and their particle size on the neutralising capacity. The tests were performed in two different anoxic conditions: in batch reactors, and in columns having a hydraulic retention time of 15?h. The results showed that the neutralisation capacity of calcite was more important than for dolomitic rock, and smaller particle size gave higher alkalinity production (fine calcite dissolved faster in contact with AMD). A characterization of metal precipitate in sludge and in limestone coating was performed and demonstrated that gypsum, lepidocrocite and goethite were the predominant secondary minerals to be formed. Finally, this study underlines that anoxic limestone drain cannot be used alone to treat high iron concentrated AMD.  相似文献   

Morphological similarities between DBM and a microeconomic model of sprawl     

Geoffrey Caruso  Gilles Vuidel  Jean Cavailhès  Pierre Frankhauser  Dominique Peeters  Isabelle Thomas 《Journal of Geographical Systems》2011,13(1):31-48

We present a model that simulates the growth of a metropolitan area on a 2D lattice. The model is dynamic and based on microeconomics. Households show preferences for nearby open spaces and neighbourhood density. They compete on the land market. They travel along a road network to access the CBD. A planner ensures the connectedness and maintenance of the road network. The spatial pattern of houses, green spaces and road network self-organises, emerging from agents individualistic decisions. We perform several simulations and vary residential preferences. Our results show morphologies and transition phases that are similar to Dieletric Breakdown Models (DBM). Such similarities were observed earlier by other authors, but we show here that it can be deducted from the functioning of the land market and thus explicitly connected to urban economic theory.  相似文献