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51.
Evaluation of snow water equivalent datasets over the Saint‐Maurice river basin region of southern Québec 下载免费PDF全文
A 10‐km gridded snow water equivalent (SWE) dataset is developed over the Saint‐Maurice River basin region in southern Québec from kriging of observed snow survey data for evaluation of SWE products. The gridded SWE dataset covers 1980–2014 and is based on manual gravimetric snow surveys carried out on February 1, March 1, March 15, April 1, and April 15 of each snow season, which captures the annual maximum SWE (SWEM) with a mean interpolation error of ±19%. The dataset is used to evaluate SWEM from a range of sources including satellite retrievals, reanalyses, Canadian regional climate models, and the Canadian Meteorological Centre operational snow depth analysis. We also evaluate a number of solid precipitation datasets to determine their contribution to systematic errors in estimated SWEM. None of the evaluated datasets is able to provide estimates of SWEM that are within operational requirements of ±15% error, and insufficient solid precipitation is determined to be one of the main reasons. The Climate System Forecast Reanalysis is the only dataset where snowfall is sufficiently large to generate SWEM values comparable to observations. Inconsistencies in precipitation are also found to have a strong impact on year‐to‐year variability in SWEM dataset performance and spread. Version 3.6.1 of the Canadian Land Surface Scheme land surface scheme driven with ERA‐Interim output downscaled by Version 5.0.1 of the Canadian Regional Climate Model was the best physically based model at explaining the observed spatial and temporal variability in SWEM (root‐mean‐square error [RMSE] = 33%) and has potential for lower error with adjusted precipitation. Operational snow products relying on the real‐time snow depth observing network performed poorly due to a lack of real‐time data and the strong local scale variability of point snow depth observations. The results underscore the need for more effort to be invested in improving solid precipitation estimates for use in snow hydrology applications. 相似文献
52.
Kathryn L. Linge L. Paul Bédard Roxana Bugoi Jacinta Enzweiler Klaus Peter Jochum Rüdiger Kilian Jingao Liu Johanna Marin‐Carbonne Silke Merchel Frans Munnik Luiz F.G. Morales Claire Rollion‐Bard A. Kate Souders Paul J. Sylvester Ulrike Weis 《Geostandards and Geoanalytical Research》2017,41(4):493-562
This GGR biennial critical review covers developments and innovations in key analytical methods published since January 2014, relevant to the chemical, isotopic and crystallographic characterisation of geological and environmental materials. In nine selected analytical fields, publications considered to be of wide significance are summarised, background information is provided and their importance evaluated. In addition to instrumental technologies, this review also presents a summary of new developments in the preparation and characterisation of rock, microanalytical and isotopic reference materials, including a précis of recent changes and revisions to ISO guidelines for reference material characterisation and reporting. Selected reports are provided of isotope ratio determinations by both solution nebulisation MC‐ICP‐MS and laser ablation‐ICP‐MS, as well as of radioactive isotope geochronology by LA‐ICP‐MS. Most of the analytical techniques elaborated continue to provide new applications for geochemical analysis; however, it is noted that instrumental neutron activation analysis has become less popular in recent years, mostly due to the reduced availability of nuclear reactors to act as a neutron source. Many of the newer applications reported here provide analysis at increasingly finer resolution. Examples include atom probe tomography, a very sensitive method providing atomic scale information, nanoscale SIMS, for isotopic imaging of geological and biological samples, and micro‐XRF, which has a spatial resolution many orders of magnitude smaller than conventional XRF. 相似文献
53.
Lécuyer Christophe Gasquet Dominique Allemand Pascal Martineau François Martinez Isabelle 《International Journal of Earth Sciences》2017,106(8):2855-2872
International Journal of Earth Sciences - Four imbricated mafic to felsic plutons of Variscan age from Morocco have been investigated for their cooling history and geochemical interactions with... 相似文献
54.
Determination of deployment specific chemical uptake rates for SPMD and PDMS using a passive flow monitor 总被引:1,自引:0,他引:1
Passive sampling techniques facilitate the time-integrated measurement of pollutant concentrations through the use of a selective receiving phase. Accurate quantification using passive sampling devices rely on the implementation of methods that will negate the effects of environmental factors (flow, temperature, etc.) or that will allow the calculation of the chemical specific rates of uptake (R(s)) into the passive sampler employed. We have applied an in situ calibration technique based on the dissolution of gypsum to measure the average water velocity to which a sampler has been exposed. We demonstrate that the loss of gypsum from the passive flow monitor (PFM) can be applied to predict changes in R(s) dependent on flow when using the absorbent SPMD (semipermeable membrane device) and PDMS (polydimethyl siloxan) passive samplers. The application of the PFM will enhance the accuracy of measurements made when calculating and reporting environmental pollutant concentrations using a passive sampling device. 相似文献
55.
Dominique Girard Sabrina Clemente Kilian Toledo-Guedes Alberto Brito José Carlos Hernández 《Marine Ecology》2012,33(3):377-385
An outbreak of bald sea urchin disease was detected affecting intertidal populations of the edible temperate species Paracentrotus lividus at its southernmost geographical limit. The mortality event was detected in three sites (Güímar, Palmar and Alcalá) off Tenerife, Canary Islands (Northeastern Atlantic), in October 2003, coinciding with the highest sea surface temperatures (SST) and the lowest wave heights of the year. The prevalence of infection reached 100% but did not affect equally all studied sites or the different size classes. The disease was more prevalent in large sea urchins (>40 mm). The prevalence appeared to be positively correlated with the environmental variable SST and negatively correlated with wave height. In October 2004, only two infected urchins were found (prevalence 1%) at one of the studied sites. However, during 2004 no such extreme values of temperature and wave height were observed. We conclude that high SSTs and low wave heights such as those observed during 2003 are conditions that may trigger outbreaks of urchin disease. 相似文献
56.
Flavien Choulet Michel Faure Dominique Cluzel Yan Chen Wei Lin Bo Wang Bei Xu 《中国科学:地球科学(英文版)》2016,59(1):25-57
The Altaid tectonic collage extends over Central Asia, exposing numerous accretionary orogens that can account for the Palaeozoic continental crust growth. A pluridisciplinary approach, using geochronological, geochemical, structural and palaeomagnetic tools was carried out to unravel the architecture and the evolution of West Junggar(Northwestern China), a segment of the Altaid Collage. A polycyclic geodynamic evolution is inferred and includes:(1) an Early Palaeozoic cycle, characterized by the closure of two oceanic basins bounded by island-arc systems;(2) an Early Devonian subduction jamming resulting in a minor-scale collision documented by thrusting, syntectonic sedimentation and subsequent crutal thinning associated with alkaline magmatism;(3) a Late Palaeozoic cycle, driven by the evolution of two opposite subduction zones developed upon the Early Palaeozoic basement. Detailed structural analysis and paleomagnetic data provide constraints for the late evolution of Junggar in the frame of the development of the Late Palaeozoic Kazakh orocline, which led to oblique subduction and transpression in the West Junggar accretionary complex. Progressive buckling of the Kazakh orocline further resulted in Late Carboniferous to Permian wrench tectonics, and lateral displacement of lithotectonic units. Block rotations that continued after the Late Triassic are due to diachronous intraplate reactivation. This scenario mirrors the Palaeozoic geodynamics of the Altaid Collage. Multiple Early Palaeozoic collisions of intra-oceanic arcs and micro continents have contributed to the formation of the Kazakhstan Microcontinent. Since the Late Palaeozoic, subductions formed around this microcontinent and the final oblique closure of oceanic domains resulted in the transcurrent collage of Tarim and Siberia cratons. Palaeozoic strike-slip faults were later reactivated during Mesozoic intracontinental tectonics. 相似文献
57.
The production of organic matter and calcium carbonate by a dense population of the brittle star Acrocnida brachiata (Echinodermata) was calculated using demographic structure, population density, and relations between the size (disk diameter)
and the ash-free dry weight (AFDW) or the calcimass. During a 2-year survey in the Bay of Seine (Eastern English Channel,
France), organic production varied from 29 to 50 gAFDW m−2 year−1 and CaCO3 production from 69 to 104 gCaCO3 m−2 year−1. Respiration was estimated between 1.7 and 2.0 molCO2 m−2 year−1. Using the molar ratio (ψ) of CO2 released: CaCO3 precipitated, this biogenic precipitation of calcium carbonate would result in an additional release between 0.5 and 0.7 molCO2 m−2 year−1 that represented 23% and 26% of total CO2 fluxes (sum of calcification and respiration). The results of the present study suggest that calcification in temperate shallow
environments should be considered as a significant source of CO2 to seawater and thus a potential source of CO2 to the atmosphere, emphasizing the important role of the biomineralization (estimated here) and dissolution (endoskeletons
of dead individuals) in the carbon budget of temperate coastal ecosystems. 相似文献
58.
J. Escuder Viruete A. Pérez-Estaún D. Weis 《International Journal of Earth Sciences》2009,98(2):407-425
The nature of the oceanic crust produced through rifting and oceanic spreading between North and South America during the
Late Jurassic is a key element for the Caribbean plate tectonic model reconstruction. Located in the Cordillera Central of
Hispaniola, the Loma La Monja volcano-plutonic assemblage (LMA) is composed of gabbros, dolerites, basalts, and oceanic sediments,
as well as metamorphic equivalents, which represent a dismembered fragment of this proto-Caribbean oceanic crust. Petrologic
and geochemical data show that the LMA have a relatively broad diversity in composition, which represent the crystallization
products of a typical low-pressure tholeiitic fractionation of mid-ocean ridge basalts (MORB)-type parental magmas, ranging
from N- to E-MORB. Three geochemical groups have been distinguished in the volcanic sequence: LREE-flat to slightly LREE-enriched
basalts of groups II and III occur interlayered in the lower stratigraphic levels; and LREE-depleted basalts of group I in
the upper levels. Mantle melt modeling suggests that group III magmas are consistent by mixing within a mantle melt column
of low-degree (<1%) melts of a deep garnet lherzolite source and high-degree (>15%) melts of a shallow spinel source, and
groups II and I magmas are explained with moderate to high (14–18%) and very high (>20%) fractional melting degrees of a shallower
spinel mantle source, respectively. Thus, upward in the volcanic sequence of the LMA, the magmas represent progressively more
extensive melting of shallower sources, in a plume-influenced spreading ridge of the proto-Caribbean oceanic crust. Nb/Y versus
Zr/Y systematics combined with recent plate tectonic model reconstructions reveal that Caribbean Colombian oceanic plateau
fragments in Hispaniola formed through melting of heterogeneous mantle source regions related with distinct plumes during
at least from Aptian–Albian (>96 Ma) to Late Campanian. 相似文献
59.
Pierre Polsenaere Nicolas Savoye Henri Etcheber Mathieu Canton Dominique Poirier Steven Bouillon Gwenaël Abril 《Aquatic Sciences - Research Across Boundaries》2013,75(2):299-319
We measured spatial and temporal variations in carbon concentrations, isotopic compositions and exports during a complete hydrological cycle in nine watercourses draining a lowland forested podzolized catchment, flowing into the Arcachon lagoon (France). In addition, integrated fluxes of CO2 across the water-atmosphere interface were estimated to assess the relative importance of CO2 evasion versus lateral carbon transport at the catchment scale. Watercourse similarities and specificities linked to the local catchment characteristics are discussed and compared with other riverine systems. Low concentrations of suspended particulate matter and particulate organic carbon (POC) were generally measured in all the watercourses (8.4 ± 3.4 and 1.6 ± 0.6 mg L?1, respectively), reflecting limited mechanical soil erosion. The generally high POC content in the suspended matter (20 %), low Chl a concentrations (1.3 ± 1.4 μg L?1) and the relatively constant δ13C-POC value (near ?28 ‰) throughout the year reveal this POC originates from terrestrial C3 plant and soil detritus. The presence of podzols leads to high levels of dissolved organic carbon (DOC; 6.6 ± 2.2 mg L?1). Similarly, high dissolved inorganic carbon (DIC) concentrations were measured in the Arcachon lagoon catchment (5.9 ± 2.2 mg L?1). The δ13C-DIC value around ?20 ‰ throughout the year in many small watercourses reveals the predominance of terrestrial carbon mineralisation and silicate rock weathering in soils as the major DIC source. With pCO2 between 1,000 and 10,000 ppmv, all watercourses were a source of CO2 to the atmosphere, particularly during the low river stage. Organic carbon parameters remained relatively stable throughout the year, whereas DIC parameters showed strong seasonal contrasts closely linked to the hydrological regime and hyporheic flows. In total, the carbon export from the Arcachon watershed was estimated at 15,870 t C year?1 or 6 t C km?2 year?1, mostly exported to the lagoon as DOC (35 %), DIC (24 %) and lost as CO2 degassing to the atmosphere (34 %). 相似文献
60.
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