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Methods are described for the complexometric determination of calcium and magnesium in seawater, using an amalgamated silver electrode for end-point detection. In the presence of a small amount of mercury(II)-chelonate, the amalgamated silver electrode serves as a pM indicator during the complexometric titration, the Hg complex being stronger than Ca, Mg and Sr complexes. Calcium is determined by titration with EGTA, calcium+magnesium+strontium by titration with EDTA and magnesium is obtained by difference. Average values of 0.02120 (standard deviation 0.00004) for Ca:Cl‰ and 0.06671 (standard deviation 0.00014) for Mg:Cl‰ were obtained for samples from tropical North Atlantic Ocean. 相似文献
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Segura Hans Junquas Clementine Espinoza Jhan Carlo Vuille Mathias Jauregui Yakelyn R. Rabatel Antoine Condom Thomas Lebel Thierry 《Climate Dynamics》2021,56(1-2):679-680
Climate Dynamics - The original version of the article contained errors in Fig. 相似文献
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E Mottin C Caplat T Latire A Mottier ML Mahaut K Costil D Barillier JM Lebel A Serpentini 《Marine pollution bulletin》2012,64(9):1911-1920
Two types of exposures were performed to assess the effects of zinc released from sacrificial anode degradation: a chronic exposure, in which oysters were exposed to 0.53±0.04mgZnL(-1) for 10weeks, and an acute exposure, where oysters were exposed to 10.2±1.2mgZnL(-1) for 1week. At the end of the acute exposure experiment, 81.8% mortality was recorded. In contrast, no mortality was detected after 10weeks exposure. Moreover, all of the immune system biomarkers studied, except the number of circulating haemocytes, were stimulated by a moderate level of zinc and inhibited by a high level. Our exposure conditions did not induce SOD or MXR mRNA expression in gills and digestive gland. However, an increase of MT mRNA is observed in these tissues. The results indicate that oysters are sensitive to acute zinc toxicity but are only moderately affected by a mild zinc concentration. 相似文献
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The Mekong: A Socio‐Legal Approach to River Basin Development Ben Boer,Philip Hirsch,Fleur Johns,Ben Saul and Natalia Scurrah. Earthscan‐Routledge,New York, 2016, pp. xiii + 252 (ISBN 978‐1‐138‐78844‐2) (hbk) (ISBN 978‐1‐138‐78845‐9) (pbk). 下载免费PDF全文
Louis Lebel 《Singapore journal of tropical geography》2016,37(3):435-437
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Relationship between point rainfall, average sampled rainfall and ground truth at the event scale in the Sahel 总被引:1,自引:0,他引:1
Geostatistical techniques are used to quantify the reference mean areal rainfall (ground truth) from sparse raingaugenetworks.
Based on the EPSAT-Niger event cumulative rainfall, a linear relationship between the ground truth considered as the mean
area rainfall estimated from the densely available raingauge network and the area rainfall estimated from sparse network are
derived. Also, a linear relationship between the ground truth and point rainfall is established. As it was reported experimentally
by some authors, the slope of these relationships is less than one. Based on the geostatistical framework, the slope and the
ordinate at the origin can be estimated as a function of the spatial structure of the rainfall process. It is shown that the
slope is smaller than one. For the special case of one gauge inside a fixed area or a Field Of View (FOV), an areal reduction
factor is derived. It has a limit value which depends only on the size of the area and the spatial structure of the rainfall
process. The relative variance error of estimating the FOV cumulative rainfall from point rainfall is also given. 相似文献
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Abstract Despite the Sahelian drought of the 1970s–1990s, the unconfined aquifer in southwest Niger exhibits a multidecadal increase in groundwater reserves. Recent changes in land surface conditions have enhanced runoff and thus indirect groundwater recharge below endorheic ponds. This paper presents a model-based investigation of surface runoff and groundwater recharge at mesoscale (~5000 km2). A new lumped-conceptual runoff model applicable to the large number of ungauged endorheic catchments is specially developed, derived from an existing fine-scale, physically-based hydrologic model. Runoff simulated for sites identified as groundwater recharge sources are used to derive recharge forcing for a Modflow-based model of the aquifer. The rising water table trend and its spatial distribution over the period 1992–2003 are generally well simulated, albeit smoothed year-to-year dynamics. Comparison with alternative methods of recharge estimation suggests, however, that there may presently exist more recharging sites and/or contributing surfaces than those considered so far. Citation Massuel, S., Cappelaere, B., Favreau, G., Leduc, C., Lebel, T. & Vischel, T. (2011) Integrated surface water–groundwater modelling in the context of increasing water reserves of a regional Sahelian aquifer. Hydrol. Sci. J. 56(7), 1242–1264. 相似文献
9.
Alexandros Makris Clémentine Prieur Théo Vischel Guillaume Quantin Thierry Lebel Rémy Roca 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(2):681-691
In this work we apply a recently proposed Bayesian multiple target tracking model to mesoscale convective systems tracking. This stochastic model follows the multiple hypothesis tracking paradigm and can handle a varying number of targets while detecting the target birth, death, split, and merge events. The model is tested experimentally with real MCS targets detected from meteosat IR data over the Sahelian region. The performance of the stochastic tracking is evaluated by comparing it qualitatively and quantitatively with well established deterministic methods. 相似文献
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Segura Hans Espinoza Jhan Carlo Junquas Clementine Lebel Thierry Vuille Mathias Garreaud Rene 《Climate Dynamics》2020,54(5):2613-2631
Climate Dynamics - Analyzing December–February (DJF) precipitation in the southern tropical Andes—STA ($$12^{\circ }\,\hbox {S}$$–$$20^{\circ }\,\hbox {S}$$; > 3000... 相似文献