Post‐fire hydrological response and suspended sediment transport of a terraced Mediterranean catchment          下载免费PDF全文

Julián García‐Comendador  Josep Fortesa  Aleix Calsamiglia  Adolfo Calvo‐Cases  Joan Estrany 《地球表面变化过程与地形》2017,42(14):2254-2265

In July 2013, a wildfire severely affected the western part of the island of Mallorca (Spain). During the first three post‐fire hydrological years, when the window of disturbance tends to be more open, the hydrological and sediment delivery processes and dynamics were assessed in a representative catchment intensively shaped by terracing that covered 37% of its surface area. A nested approach was applied with two gauging stations (covering 1.2 km² and 4.8 km²) built in September 2013 that took continuous measurements of rainfall, water and sediment yield. Average suspended sediment concentration (1503 mg L^?1) and the maximum peak (33 618 mg L^?1) were two orders of magnitude higher than those obtained in non‐burned terraced catchments of Mallorca. This factor may be related to changes in soils and the massive incorporation of ash into the suspended sediment flux during the most extreme post‐fire event; 50 mm of rainfall in 15 min, reaching an erosivity of 2886 MJ mm ha^?1 h^?1. Moreover, hysteretic counter‐clockwise loops were predominant (60%), probably related to the increased sensitivity of the landscape after wildfire perturbation. Though the study period was average in terms of total annual precipitation (even higher in intensities), minimal runoff (2%) and low sediment yield (6.3 t km^?2 y^?1) illustrated how the intrinsic characteristics of the catchment, i.e. calcareous soils, terraces and the application of post‐fire measures, limited the hydrosedimentary response despite the wildfire impact. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Identifying Variable γ-ray Sources Through Radio Observations     

Josep M. Paredes  J. Martí  D. F. Torres  G. E. Romero  J. A. Combi  V. Bosch-Ramon  J. García-Sáanchez 《Astrophysics and Space Science》2005,297(1-4):223-233

We present preliminary results of a campaign undertaken with different radio interferometers to observe a sample of the most variable unidentified EGRET sources. We expect to detect which of the possible counterparts of the γ-ray sources (any of the radio emitters in the field) varies in time with similar timescales as the γ-ray variation. If the γ-rays are produced in a jet-like source, as we have modelled theoretically, synchrotron emission is also expected at radio wavelengths. Such radio emission should appear variable in time and correlated with the γ-ray variability.  相似文献   

An arbitrary high-order discontinuous Galerkin method for elastic waves on unstructured meshes – IV. Anisotropy     

Josep de la Puente  Martin Käser  Michael Dumbser  Heiner Igel 《Geophysical Journal International》2007,169(3):1210-1228

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Predicting strain using forward modelling of restored cross-sections: Application to rollover anticlines over listric normal faults     

Josep Poblet  Mayte Bulnes   《Journal of Structural Geology》2007,29(12):1960-1970

A strategy to predict strain across geological structures, based on previous techniques, is modified and evaluated, and a practical application is shown. The technique, which employs cross-section restoration combined with kinematic forward modelling, consists of restoring a section, placing circular strain markers on different domains of the restoration, and forward modelling the restored section with strain markers until the present-day stage is reached. The restoration algorithm employed must be also used to forward model the structure. The ellipses in the forward modelled section allow determining the strain state of the structure and may indirectly predict orientation and distribution of minor structures such as small-scale fractures. The forward model may be frozen at different time steps (different growth stages) allowing prediction of both spatial and temporal variation of strain. The method is evaluated through its application to two stages of a clay experiment, that includes strain markers, and its geometry and deformation history are well documented, providing a strong control on the results. To demonstrate the method's potential, it is successfully applied to a depth-converted seismic profile in the Central Sumatra Basin, Indonesia. This allowed us to gain insight into the deformation undergone by rollover anticlines over listric normal faults.  相似文献   

Morphometric indices as indicators of tectonic,fluvial and karst processes in calcareous drainage basins,South Menorca Island,Spain     

Francesca S. Segura  Josep E. Pardo‐Pascual  Vicenç M. Rosselló  Joan J. Fornós  Bernadí Gelabert 《地球表面变化过程与地形》2007,32(13):1928-1946

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Size Fraction Effects on Planktonic Foraminifera Assemblages: A Compositional Contribution to the Golden Sieve Rush     

Valentino Di Donato  Josep Daunis-i-Estadella  Josep A. Martín-Fernández  Paola Esposito 《Mathematical Geosciences》2015,47(4):455-470

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Report on the 4th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the “Kilian Group” (Dijon, France, 30th August 2010)     

Stéphane Reboulet  Peter F. Rawson  Josep A. Moreno-Bedmar  Maria B. Aguirre-Urreta  Ricardo Barragán  Yuri Bogomolov  Miguel Company  Celestina González-Arreola  Vyara Idakieva Stoyanova  Alexander Lukeneder  Bertrand Matrion  Vasily Mitta  Hasina Randrianaly  Zdenek Vaši?ek  Evgenij J. Baraboshkin  Didier Bert  Stéphane Bersac  Tamara N. Bogdanova  Luc G. Bulot  Jean-Louis Latil  Irina A. Mikhailova  Pierre Ropolo  Ottilia Szives 《Cretaceous Research》2011,32(6):786-793

The 4th Kilian Group meeting (Dijon, France, 30th August 2010) focused on the Aptian and Albian Stages. For the Aptian, a two-fold division of the stage was adopted for the Mediterranean area with a boundary between the Dufrenoyia furcata and Epicheloniceras martini Zones. The main changes to the zonal scheme concern the Lower Aptian with: the introduction of a Deshayesites luppovi Subzone in the upper part of the Deshayesites oglanlensis Zone; the replacement of Deshayesites weissi by Deshayesites forbesi as new index-species of the second interval zone; the introduction of a Roloboceras hambrovi Subzone in the upper part of the D. forbesi Zone; and the subdivision of the D. furcata Zone into the D. furcata and Dufrenoyia dufrenoyi Subzones. For the Albian, the upper part of the Douvilleiceras mammillatum Zone (Lower Albian) is now characterized by a Lyelliceras pseudolyelli Subzone. The main amendments concern the Upper Albian. The base of this substage is defined by the base of the Dipoloceras cristatum Zone. Above it, the Upper Albian zonal scheme comprises in stratigraphic order the Mortoniceras pricei, Mortoniceras inflatum, Mortoniceras fallax, Mortoniceras rostratum, Mortoniceras perinflatum and Arrhaphoceras briacensis Zones.  相似文献   

Origin of rare earth element anomalies in mangrove sediments,Sepetiba Bay,SE Brazil: used as geochemical tracers of sediment sources     

Emmanoel V. Silva-Filho  Christian J. Sanders  Michel Bernat  Ana M. G. Figueiredo  Silvia M. Sella  Julio Wasserman 《Environmental Earth Sciences》2011,64(5):1257-1267

Elemental contents were determined in two mangrove habitats along Sepetiba Bay, SE Brazil, an area impacted by local industrial activities, as well as hinterland water diversion networks. This study demonstrates how specific REEs (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) may be used as a sediment source tracer to mangrove-dominated coastlines. From the two stations studied, a pair of cores was collected, one in the mangrove forest and the other in the tidal flat. Station 1 results show a general enrichment in most of the fractioned patterns of the REEs normalised by Post-Archean Australian Shale. The relatively light rare earth elements are similarly enriched in the generally more polluted Station 1. Despite the probable difference in background sediment characteristics, a common sharp increase in mud contents patterns in the upper part of the mangrove sediment core was related to a lower REE content as well as Eu anomalies. With existing knowledge of clockwise water circulation in the bay, these patterns can be explained by man-made water diversion from the São Francisco and Guandu rivers, initiated more than 30 years ago, whereby suspended matter with relatively large contents of REEs and material originating from industrial sources accumulate in the eastern sector of the bay. This is the first comprehensive assessment of REEs as sedimentary tracers in a mangrove ecosystem in Brazil.  相似文献   

Coastal Mediterranean plankton stimulation dynamics through a dust storm event: An experimental simulation     

Estela Romero  Francesc Peters  Cèlia Marrasé  Òscar Guadayol  Josep M. Gasol  Markus G. Weinbauer 《Estuarine, Coastal and Shelf Science》2011

An enhancement of aeolian inputs to the ocean due to a future increase in aridity in certain parts of the world is predicted from global change. We conducted an experimental simulation to assess the biological response of NW Mediterranean coastal surface waters to an episodic dust addition. On the assumption that planktonic growth was limited by phosphorus, dust effects were compared to those induced by equivalent enrichments of phosphate. The experiment analyzed the dynamics of several parameters during one week: inorganic nutrients, total and fractioned chlorophyll a, bacterial abundance, phytoplankton species composition, abundance of autotrophic and heterotrophic flagellates, particulate organic carbon and particulate organic nitrogen. The maximum addition of dust (0.5 g dust L⁻¹) initiated an increase in bacterial abundance. After 48 h, bacterial numbers decreased due to a peak in heterotrophic flagellates and a significant growth of autotrophic organisms, mainly nanoflagellates but also diatoms, was observed. Conversely, lower inputs of dust (0.05 g dust L⁻¹) and phosphate enrichments (0.5 μmol PO₄³⁻ L⁻¹) only produced increases in phototrophic nanoflagellates. In our experiment, dust triggered bacterial growth, changed phytoplankton dynamics and affected the ratio of autotrophic to heterotrophic biomass, adding to the variability in the sources that affect system dynamics, energy and carbon budgets and ultimately higher trophic levels of the coastal marine food web.  相似文献   

On the Origin of the 1999 Leonid Storm as Deduced from Photographic Observations     

Trigo-Rodríguez  Josep M.  Llorca  Jordi  Fabregat  Juan 《Earth, Moon, and Planets》2002,91(2):107-119

Photographic multi-station observations of 18 Leonid meteorsobtained by the Spanish Photographic Meteor Network are presented. For each meteoroidthe radiant position, trajectory data and orbital parameters are discussed and compared totheoretical radiant positions and orbital elements of particles ejected from 55P/Tempel–Tuttle in 1899.We discuss the role of mean velocity imprecision in the dispersion of some orbital parameters,specially the semimajor axis. Finally, by applying the dust trail theory we have adjusted the1999 Leonidstorm orbits to a defined semimajor axis value to test the quality of photographic observations.  相似文献