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141.
Impact of the Rhône and Durance valleys on sea-breeze circulation in the Marseille area 总被引:2,自引:0,他引:2
Sophie Bastin Philippe Drobinski Alain Dabas Patricia Delville Oliver Reitebuch Christian Werner 《Atmospheric Research》2005,74(1-4):303-328
Sea-breeze dynamics in the Marseille area, in the south of France, is investigated in the framework of the ESCOMPTE experiment conducted during summer 2001 in order to evaluate the role of thermal circulations on pollutant transport and ventilation. Under particular attention in this paper is the sea-breeze channelling by the broad Rhône valley and the narrow Durance valley, both oriented nearly-north–south, i.e., perpendicular to the coastline, and its possible impact on the sea-breeze penetration, intensity and depth, which are key information for air pollution issues. One situation of slight synoptic pressure gradient leading to a northerly flow in the Rhône valley (25 June 2001) and one situation of a weak onshore prevailing synoptic wind (26 June 2001) are compared. The impact of the Rhône and Durance valleys on the sea-breeze dynamics on these two typical days is generalized to the whole ESCOMPTE observing period.The present study shows by combining simple scaling analysis with wind data from meteorological surface stations and Doppler lidars that (i) the Durance valley always affects the sea breeze by accelerating the flow. A consequence is that the Durance valley contributes to weaken the temperature gradient along the valley and thus the sea-breeze circulation. In some cases, the acceleration of the channelled flow in the Durance valley suppresses the sea-breeze flow by temperature gradient inhibition; (ii) the Rhône valley does not generally affect the sea breeze significantly. However, if the sea breeze is combined with an onshore flow, it leads to further penetration inland and intensification of the low-level southerly flow. In this situation, lateral constriction may accelerate the sea breeze. Simple scaling analysis suggests that Saint Paul (44.35°N, about 100 km from the coastline) is the lower limit where sea breeze can be affected by the Rhône valley. These conclusions have implications in air quality topics as channelled sea breeze may advect far inland pollutants which may be incorporated into long-range transport, particularly in the Durance valley. 相似文献
142.
The point of departure for this article is the contemporary tendency towards localisation of politics in the context of neo-liberal globalisation. Mediated through institutional reforms, political discourses and localised struggles, this localisation of politics produce new and transformed local political spaces. The purpose of the article is to examine the capacity of popular movements to use and transform such political spaces within the South African housing sector. This analysis is done through a combination of conceptual examination of political space and actor capacity and a concrete case study of the political strategies and capacities of The South African Homeless People’s Federation. The article argues that the Federation has utilised political relations at different scales to mobilise resources such as land and subsidies for housing for its members. It has also influenced the formulation of housing policies through its discourses and practical experiences with people-driven housing processes. In consequence the Federation’s ability to function as a civil/political movement has granted them a certain capacity to participate in the complicated process of turning de jure rights to adequate shelter into de facto rights for the urban poor as citizens of a democratic South Africa. 相似文献
143.
Sophie Denimal Nicolas Tribovillard Florent Barbecot Laurent Dever 《Environmental Geology》2002,42(8):966-981
In northern France, the weathering and oxidation of pyrite-containing coal mine spoils can lead to sulphate enrichment of the underlying chalk aquifer. Two sites have been studied: in a free water-table zone and in a confined-aquifer zone. Solid-fraction analyses have shown a release of carbon and sulphur from the waste dump surfaces. The groundwater isotopic analysis (notably 34S) showed the existence of two sulphate sources (mine spoils and gypsum contained in Cenozoic formations). This study also saw evidence of bacterial sulphate reduction in the confined zone as a result of the release of carbon from mine spoils. The effects of acid mine drainage were the presence of secondary minerals as small jarosite dots (cm) present at depth, gypsum or ferrihydrite present on the bottom of temporary ponds, and an increase in sulphate content of groundwaters sampled downstream of the waste dumps. This acid mine drainage is buffered during its infiltration into the chalk aquifer. This is evidenced by the increase in magnesium, calcium, bicarbonate or strontium, resulting of carbonate digestion downstream of the sites. No significant leaching of metals, even those associated with the sulphide fraction, was seen at the two studied sites. 相似文献
144.
Today, various types of fair trade systems propose new forms of relationships between producers and consumers. If several
studies have provided accurate understandings of consumers’ motivations to buy fair trade products, the specific kinds of
consumer involvement that are emphasized in those systems remain partly unknown. In France, controversies about the regulation
and organization of fair trade with producers from Southern countries has led to broader debates about how consumers can best
express their solidarity with producers. In these debates local food networks are often portrayed as good examples of fair
trade and as having potential to redefine the role of the consumer in the marketplace (or in commercial relations). Based
on examination of the type of mechanisms used to enrol consumers in local and fair trade networks, we have distinguished two
main kinds of consumers’ involvement. The first one may be called “delegation” and is based on market mechanisms. The second
one is called “empowerment” and is based on contractual mechanisms between consumers and producers and on the construction
of collective choices. This latter kind of consumer involvement points out the capacity of alternative food networks to empower
consumers in a more broadly political sense.
相似文献
Claire LamineEmail: |
145.
Sophie Decre Thierry De Putter Johan Yans Bchir Moussi Philippe Recourt Fakher Jamoussi Delphine Bruyre Christian Dupuis 《Ore Geology Reviews》2008,33(3-4):397-410
The Tamra iron mine (Nefza mining district, N. Tunisia) has been exploited for about one century. There are, however, very few publications modelling the mineralisation within this 50 m-thick Messinian–Zanclean sedimentary series. We present the result of a detailed sedimentological, mineralogical and geochemical study on the siliciclastic sediments heavily mineralised in iron. In their present state of preservation, these are rather unusual sediments, wherein most of sedimentological information is obliterated by iron impregnation. The whole series consists of a succession of fining-upward sequences (a few meters in thickness) that are capped by clay-bearing variegated and mottled horizons, each sequence being interpreted as a shallowing-upward sequence topped by an emersive horizon corresponding to a paleosoil. We propose that alteration and/or pedogenesis by the downward percolation of meteoric fluids accounts for most of the initial iron concentration, while a hydrothermal overprint, linked to the neighbouring Miocene magmatic rocks and associated mineral deposits (Sidi Driss Fe–Pb–Zn mine), accounts for the existing extreme iron enrichment. The proposed model is likely to apply to several other iron mines linked to the Miocene magmatic activity in the whole Maghreb area, and especially along the Apenninic thrust front (locally known as Tell-Rif front). 相似文献
146.
147.
As a result of burgeoning social and environmental issues, localisation movements such as Transition Towns are emerging. However, tension exists as to the best scale and method to create and maintain this community activism. In this study, we explore the activities of two Transition Towns in Aotearoa New Zealand through a qualitative mixed methodology, and argue that relational notions of scale and the notion of progressive localisms enable an appreciation of the locally rooted but outward looking nature of Transition activities. In turn, this creates space to acknowledge the diffuse nature of change, redefine success and sustain momentum. 相似文献
148.
— We have tested to which extent commonly used dynamic rupture parameters can be resolved for a realistic earthquake scenario from all available observations. For this purpose we have generated three dynamic models of the Landers earthquake using a single, vertical, planar fault with heterogeneity in either the initial stress, the yield stress, or the slip-weakening distance. Although the dynamic parameters for these models are inherently different, all the simulations are in agreement with strong motion, GPS, InSAR, and field data for the event. The rupture propagation and slip distributions obtained for each model are similar, showing that the solution of the dynamic problem is non-unique. In other words, it is not always possible to separate strength drop and the slip-weakening distance using rupture modeling, in agreement with the conclusions by GUATTERI and SPUDICH (2000). 相似文献
149.
Spatial mode estimation for functional random fields with application to bioturbation problem 总被引:1,自引:1,他引:0
Sophie Dabo-Niang Anne-Francoise Yao Laura Pischedda Philippe Cuny Franck Gilbert 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(4):487-497
This work provides a useful tool to study the effects of bioturbation on the distribution of oxygen within sediments. We propose
here heterogeneity measurements based on functional spatial mode. To obtain the mode, one usually needs to estimate the spatial
probability density. The approach considered here consists in looking each observation as a curve that represents the history
of the oxygen concentration at a fixed pixel. 相似文献
150.
Alix Toulier Jean-Lambert Join Pierre Staménoff Yoan Benoit Geneviève Lebeau Maxime Gautier Caroline Gorge Eric Gayer Emmanuel Cordier Victor Kbidi Guillaume Payen Magali David Sophie Ferreira François Bonnardot Julien Bonnier Stéphane Martel Jimmy Gonthier Emilie Roulleau Jean-Pierre Cammas Dominique Strasberg Olivier Flores Fabrice R. Fontaine Thomas Giambelluca Claudine Ah-Peng 《水文研究》2024,38(2):e15061
Tropical volcanic islands are biodiversity hotspots where the Critical Zone (CZ) still remains poorly studied. In such steep topographic environments associated with extreme climatic events (cyclones), deployment and maintenance of monitoring equipment is highly challenging. While a few Critical Zone Observatories (CZOS) are located in tropical volcanic regions, none of them includes a Tropical Montane Cloud Forest (TMCF) at the watershed scale. We present here the dataset of the first observatory from the French network of critical zone observatories (OZCAR) located in an insular tropical and volcanic context, integrating a ‘Tropical Montane Cloud Forest’: The ERORUN-STAFOR observatory. This collaborative observatory is located in the northern part of La Réunion island (Indian Ocean) within the 45.0 km2 watershed of Rivière des Pluies (i.e., Rainfall river) which hosts the TMCF of Plaines des Fougères, one of the best preserved natural habitats in La Réunion Island. Since 2014, the ERORUN-STAFOR monitoring in collaboration with local partners collected a multidisciplinary dataset with a constant improvement of the instrumentation over time. At the watershed scale and in its vicinity, the ERORUN-STAFOR observatory includes 10 measurement stations covering the upstream, midstream and downstream part of the watershed. The stations record a total of 48 different variables through continuous (sensors) or periodic (sampling) monitoring. The dataset consists of continuous time series variables related to (i) meteorology, including precipitation, air temperature, relative humidity, wind speed and direction, net radiation, atmospheric pressure, cloud water flux, irradiance, leaf wetness and soil temperature, (ii) hydrology, including water level and temperature, discharge and electrical conductivity (EC) of stream, (iii) hydrogeology, including (ground)water level, water temperature and EC in two piezometers and one horizontally drilled groundwater gallery completed by soil moisture measurements under the canopy. The dataset is completed by periodic time series variables related to (iv) hydrogeochemistry, including field parameters and water analysis results. The periodic sampling survey provides chemical and isotopic compositions of rainfall, groundwater, and stream water at different locations of this watershed. The ERORUN-STAFOR monitoring dataset extends from 2014 to 2022 with an acquisition frequency from 10 min to hourly for the sensor variables and from weekly to monthly frequency for the sampling. Despite the frequent maintenance of the monitoring sites, several data gaps exist due to the remote location of some sites and instrument destruction by cyclones. Preliminary results show that the Rivière des Pluies watershed is characterized by high annual precipitation (>3000 mm y−1) and a fast hydrologic response to precipitation (≈2 h basin lag time). The long-term evolution of the deep groundwater recharge is mainly driven by the occurrence of cyclone events with a seasonal groundwater response. The water chemical results support existing hydrogeological conceptual models suggesting a deep infiltration of the upstream infiltrated rainfall. The TMCF of Plaine des Fougères shows a high water storage capacity (>2000% for the Bryophytes) that makes this one a significant input of water to groundwater recharge which still needs to be quantified. This observatory is a unique research site in an insular volcanic tropical environment offering three windows of observation for the study of critical zone processes through upstream-midstream-downstream measurements sites. This high-resolution dataset is valuable to assess the response of volcanic tropical watersheds and aquifers at both event and long-term scales (i.e., global change). It will also provide insights in the hydrogeological conceptual model of volcanic islands, including the significant role of the TMCFs in the recharge processes as well as the watershed hydrosedimentary responses to extreme climatic events and their respective evolution under changing climatic conditions. All data sets are available at https://doi.org/10.5281/zenodo.7983138 . 相似文献