Hydrology needed to manage droughts: the 2015 European case   总被引：1，自引：0，他引：1       下载免费PDF全文

Henny A.J. Van Lanen  Gregor Laaha  Daniel G. Kingston  Tobias Gauster  Monica Ionita  Jean‐Philippe Vidal  Radek Vlnas  Lena M. Tallaksen  Kerstin Stahl  Jamie Hannaford  Claire Delus  Miriam Fendekova  Luis Mediero  Christel Prudhomme  Ekaterina Rets  Renata J. Romanowicz  Sébastien Gailliez  Wai Kwok Wong  Mary‐Jeanne Adler  Veit Blauhut  Laurie Caillouet  Silvia Chelcea  Natalia Frolova  Lukas Gudmundsson  Martin Hanel  Klaus Haslinger  Maria Kireeva  Marzena Osuch  Eric Sauquet  James H. Stagge  Anne F. Van Loon 《水文研究》2016,30(17):3097-3104

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Effect of the North Atlantic Oscillation on winter daily rainfall and runoff in the Abruzzo region (Central Italy)     

L. Vergni  F. Todisco  B. Di Lena  F. Mannocchi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(7):1901-1915

In this paper a composite analysis was used to assess the influence of the North Atlantic Oscillation (NAO) on the winter daily rainfall and seasonal runoff at 28 stations of the Abruzzo region (Central Italy) during the period 1951–2012. Compositing was based on NAO^? and NAO⁺ phases, identified by mean winter values of the normalized NAO index (NAOI) ≤?0.75 and ≥+0.75, respectively. In accordance with previous studies, it was found that NAO^? phases determine, in general, a greater number of wet days (N _w ) and (consequently) higher seasonal rainfall amounts in comparison to NAO⁺ phases. However, the NAO influence is characterized by a certain spatial variability, that can mostly be explained by orographic effects due to the Apennine Mountains. This is particularly evident for the mean rainfall depth per event (P _e ) that, during NAO^? phases, increases for the stations to the west of the Apennines, while it decreases for most of the stations to the east. The structure of winter daily rainfall of NAO⁺ and NAO^? type, was described by a simple but effective first-order Markov process, determining the transition probabilities P01 (dry to wet) and P10 (wet to dry) and modelling the rainfall depth on wet days by a Weibull distribution. The most significant influence of NAO concerns P01 and the shape parameter of the Weibull distribution that are both higher during the NAO^? phase. This means that NAO^? phases are characterized by less persistent dry periods and less variable daily rainfall depths, in comparison to NAO⁺ phases. The effect of these differences on the winter seasonal runoff was explored by applying a Curve Number rainfall-runoff model. Significant increments of the mean seasonal runoff during NAO^? phases were observed only for few stations (mainly on the west), characterized by corresponding increments of N _w , P _tot and P _e .). NAO⁺ phases, instead, are characterized by relevant increments of the seasonal runoff variability, particularly on the eastern areas. In this context, the important regulating function of the watershed conditions was also discussed.  相似文献   

Submarine ridges do not prevent large-scale dispersal of abyssal fauna: A case study of Mesocletodes (Crustacea, Copepoda, Harpacticoida)     

Lena Menzel  Kai Horst GeorgePedro Martínez Arbizu 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(8):839-864

We examined the large-scale distribution of deep-sea harpacticoid copepods at the species level, in order to clarify the underlying processes of copepod dispersal. The study was based on samples collected from 12 regions and a total of 113 stations: 57 stations at depths between 1107 and 5655 m on abyssal plains in the South and North Atlantic, Southern Ocean, southern Indian Ocean, and the Pacific Ocean, and 56 stations above 900 m in the North Atlantic and eastern Mediterranean Sea.We chose the genus Mesocletodes Sars, 1909 as an ideal group to study the large-scale distribution of harpacticoid copepods in the deep oceans. Clear apomorphies and a comparatively large body size of about 1 mm allow rapid recognition of allied species in meiofauna samples. In addition, Mesocletodes represents more than 50% of the family Argestidae Por, 1986, one of the most abundant harpacticoid families in the deep sea.The geographical distributions of 793 adult females of Mesocletodes belonging to 61 species throughout the South and North Atlantic, Southern Ocean, southern Indian Ocean, Pacific Ocean, and eastern Mediterranean Sea indicated that most species are cosmopolitan. Neither the topography of the sea bottom nor long distances seem to prevent species from dispersing. Passive transport by bottom currents after resuspension is likely the propulsive factor for the dispersal of Harpacticoida, while plate tectonics and movement of individuals in the sediment may play relatively minor roles.  相似文献   

Interdisciplinary approaches: towards new statistical methods for phenological studies     

Irene Lena Hudson 《Climatic change》2010,100(1):143-171

The importance of global environmental questions has significantly advanced the impact of climate change phenology. Whilst spatial applications continue to be a core application of phenology; in recent years the temporal dimension has also been revisited, with studies showing that temporal changes, either with a natural or an anthropogenic origin, have significantly altered phenological rhythms and seasonal development—changes attributed now to an anthropogenically induced temperature increase. This paper explores and introduces recent and newly developing analytic methods in phenology; with a view to increasing an interdisciplinary perspective and dialogue. Of particular focus is how we can and best deal with nonlinearity of phenological change in time and with multiple location studies; rigorously model the inherent multivariate time series structures in climate-phenology data; further Bayesian and non-Bayesian methods, detect multiple change-points; map seasonality calendars; model de-synchronisation of species globally; invoke old fashioned, yet rarely used circular statistical methods; adapt new transitional state modelling of phenophases with respect to climate and progress a unified paradigm for meta analytic studies in phenology. The provision of uncertainty analysis is also still much needed in climate-related phenological research. Reaching consensus on design, method of data collection and comparable analytic methods is integral to advancing the generalisability of phenological results; as is a consensus on inclusion criterion for studies selected for phenological meta-analytic studies. A coherent nomenclature is critically required, but it is currently lacking in many areas of phenology.  相似文献   

Sectioning effects of porphyritic chondrules: Implications for the PP/POP/PO classification and correcting modal abundances of mineralogically zoned chondrules     

Jens Barosch  Dominik C. Hezel  Lena Sawatzki  Lucia Halbauer  Yves Marrocchi 《Meteoritics & planetary science》2020,55(5):993-999

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A combined spectrophotometric and morphometric study of the lunar mare dome fields near Cauchy, Arago, Hortensius, and Milichius     

Christian Wöhler  Raffaello Lena  Jim Phillips  Zac Pujic  Geologic Lunar Research Group 《Icarus》2006,183(2):237-264

In this study we examine the spectral and morphometric properties of the four important lunar mare dome fields near Cauchy, Arago, Hortensius, and Milichius. We utilize Clementine UV-vis multispectral data to examine the soil composition of the mare domes while employing telescopic CCD imagery to compute digital elevation maps in order to determine their morphometric properties, especially flank slope, height, and edifice volume. After reviewing previous attempts to determine topographic data for lunar domes, we propose an image-based 3D reconstruction approach which is based on a combination of photoclinometry and shape from shading. Accordingly, we devise a classification scheme for lunar mare domes which is based on a principal component analysis of the determined spectral and morphometric features. For the effusive mare domes of the examined fields we establish four classes, two of which are further divided into two subclasses, respectively, where each class represents distinct combinations of spectral and morphometric dome properties. As a general trend, shallow and steep domes formed out of low-TiO₂ basalts are observed in the Hortensius and Milichius dome fields, while the domes near Cauchy and Arago that consist of high-TiO₂ basalts are all very shallow. The intrusive domes of our data set cover a wide continuous range of spectral and morphometric quantities, generally characterized by larger diameters and shallower flank slopes than effusive domes. A comparison to effusive and intrusive mare domes in other lunar regions, highland domes, and lunar cones has shown that the examined four mare dome fields display such a richness in spectral properties and 3D dome shape that the established representation remains valid in a more global context. Furthermore, we estimate the physical parameters of dome formation for the examined domes based on a rheologic model. Each class of effusive domes defined in terms of spectral and morphometric properties is characterized by its specific range of values for lava viscosity, effusion rate, and duration of the effusion process. For our data set we report lava viscosities between about 10² and , effusion rates between 25 and , and durations of the effusion process between three weeks and 18 years. Lava viscosity decreases with increasing R₄₁₅/R₇₅₀ spectral ratio and thus TiO₂ content; however, the correlation is not strong, implying an important influence of further parameters like effusion temperature on lava viscosity.  相似文献   

Is atmospheric carbon dioxide removal a game changer for climate change mitigation?     

Elmar Kriegler  Ottmar Edenhofer  Lena Reuster  Gunnar Luderer  David Klein 《Climatic change》2013,118(1):45-57

The ability to directly remove carbon dioxide from the atmosphere allows the decoupling of emissions and emissions control in space and time. We ask the question whether this unique feature of carbon dioxide removal technologies fundamentally alters the dynamics of climate mitigation pathways. The analysis is performed in the coupled energy-economy-climate model ReMIND using the bioenergy with CCS route as an application of CDR technology. BECCS is arguably the least cost CDR option if biomass availability is not a strongly limiting factor. We compare mitigation pathways with and without BECCS to explore the impact of CDR technologies on the mitigation portfolio. Effects are most pronounced for stringent climate policies where BECCS is a key technology for the effectiveness of carbon pricing policies. The decoupling of emissions and emissions control allows prolonging the use of fossil fuels in sectors that are difficult to decarbonize, particularly in the transport sector. It also balances the distribution of mitigation costs across future generations. CDR is not a silver bullet technology. The largest part of emissions reductions continues to be provided by direct mitigation measures at the emissions source. The value of CDR lies in its flexibility to alleviate the most costly constraints on mitigating emissions.  相似文献   

Enthalpy of formation of sulfate green rusts     

Lena Mazeina  Alexandra Navrotsky  Darby Dyar 《Geochimica et cosmochimica acta》2008,72(4):1143-1153

As a contribution to the systematic study of iron oxide thermodynamics, this work reports enthalpies of formation of green rust, a double layered (Fe^II, Fe^III) hydroxide with the ideal stoichiometry , with sulfate as the anion in the interlayer. Samples were characterized by X-ray powder diffraction, thermogravimetric analysis, infrared spectroscopy, and Mössbauer spectroscopy. Full chemical analysis was performed. Contents of Fe^II, Fe^III, water, and sulfate were obtained. We report standard enthalpies of formation for green rust with different Fe^II/Fe^III ratios. Enthalpies of formation from single cation compounds, namely, Fe(OH)₂, Fe(OH)₃, FeSO₄ and H₂O show reasonable agreement with Gibbs free energies of formation from single cation compounds recalculated from the reported literature values. These values show that green rust has little stabilization over a mechanical mixture of these single cation compounds and there is no thermodynamic preference for any particular Fe^II/Fe^III ratio.  相似文献   

Timing of multiple hydrothermal events in the iron oxide–copper–gold deposits of the Southern Copper Belt,Carajás Province,Brazil     

Carolina?P.?N.?MoretoEmail author  Lena?V.?S.?Monteiro  Roberto?P.?Xavier  Robert?A.?Creaser  S.?Andrew?DuFrane  Gustavo?H.?C.?Melo  Marco?A.?Delinardo da Silva  Colombo?C.?G.?Tassinari  Kei?Sato 《Mineralium Deposita》2015,50(5):517-546

The Southern Copper Belt, Carajás Province, Brazil, hosts several iron oxide–copper–gold (IOCG) deposits, including Sossego, Cristalino, Alvo 118, Bacuri, Bacaba, Castanha, and Visconde. Mapping and U–Pb sensitive high-resolution ion microprobe (SHRIMP) IIe zircon geochronology allowed the characterization of the host rocks, situated within regional WNW–ESE shear zones. They encompass Mesoarchean (3.08–2.85 Ga) TTG orthogneiss, granites, and remains of greenstone belts, Neoarchean (ca. 2.74 Ga) granite, shallow-emplaced porphyries, and granophyric granite coeval with gabbro, and Paleoproterozoic (1.88 Ga) porphyry dykes. Extensive hydrothermal zones include albite–scapolite, biotite–scapolite–tourmaline–magnetite alteration, and proximal potassium feldspar, chlorite–epidote and chalcopyrite formation. U–Pb laser ablation multicollector inductively coupled mass spectrometry (LA-MC-ICP-MS) analysis of ore-related monazite and Re–Os NTIMS analysis of molybdenite suggest multiple Neoarchean (2.76 and 2.72–2.68 Ga) and Paleoproterozoic (2.06 Ga) hydrothermal events at the Bacaba and Bacuri deposits. These results, combined with available geochronological data from the literature, indicate recurrence of hydrothermal systems in the Southern Copper Belt, including 1.90–1.88-Ga ore formation in the Sossego–Curral ore bodies and the Alvo 118 deposit. Although early hydrothermal evolution at 2.76 Ga points to fluid migration coeval with the Carajás Basin formation, the main episode of IOCG genesis (2.72–2.68 Ga) is related to basin inversion coupled with Neoarchean (ca. 2.7 Ga) felsic magmatism. The data suggest that the IOCG deposits in the Southern Copper Belt and those in the Northern Copper Belt (2.57-Ga Salobo and Igarapé Bahia–Alemão deposits) do not share a common metallogenic evolution. Therefore, the association of all IOCG deposits of the Carajás Province with a single extensive hydrothermal system is precluded.  相似文献   

Ant mounds as a source of sediment in a tropical rainforest?          下载免费PDF全文

Lena Katharina Schmidt  Alexander Zimmermann  Helmut Elsenbeer 《水文研究》2014,28(13):4156-4160

In Lutzito catchment on Barro Colorado Island, Panama, extraordinarily high suspended‐sediment yields of 1–2 Mg ha^?1 year^?1 were generated despite the dense forest cover coinciding with erosion‐resistant soils. We hypothesized that ant mounding activity is an important zoogeomorphological mechanism in this area, providing relevant quantities of easily transportable material at the soil surface. To test this hypothesis, all ant mound material was collected collected for dry mass determination from thirty 4 m² plots installed in the study area every 1–3 days during the 39‐day sampling period. Additionally, three ground‐nesting ant species responsible for mounds in the study area, Ectatomma ruidum, Trachymyrmex cornetzi and Strumigenys marginiventris, were identified. On the basis of the total of 1.38 kg of material collected in the wet season of 2011, the estimate for the whole 8 months wet season amounts to 725 kg ha^?1. As this value is in the same order of magnitude as sediment output, it shows that ants may act as important ecosystem engineers and contribute to sediment production here by providing large quantities of fine‐grained, readily erodible material at the soil surface for subsequent transport to the streambed. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献