A review of runoff generation and soil erosion across scales in semiarid south-eastern Spain   总被引：3，自引：0，他引：3  

Y. Cantón  A. Solé-Benet  J. de Vente  C. Boix-Fayos  A. Calvo-Cases  C. Asensio  J. Puigdefábregas 《Journal of Arid Environments》2011,75(12):1254-1261

Climate, lithology, soil and especially, intense land use/cover changes, make SE Spain very vulnerable to runoff generation and water erosion leading to loss of nutrients and organic matter and to infrequent but devastating floods, reservoir siltation and mass failures. This susceptibility has led to heavy economic investment and research efforts since the 1980s, making this region a worldwide reference for understanding the hydrology and geomorphology of semiarid ecosystems. Runoff and soil erosion have been intensively studied throughout the last decades in various natural ecosystems as well as in abandoned farmlands. Research has considered a wide range of methods and spatial and temporal scales. This paper reviews the methods and data describing runoff generation and water erosion, synthesising the key processes involved, rates, thresholds and controlling factors from a scale-dependent perspective. It also identifies the major gaps in current knowledge to provide recommendations for further research towards solutions that reduce the negative impacts of erosion. Research in SE Spain has contributed significantly to a better understanding of the effect of spatial and temporal scale on runoff and sediment yield measurements, and highlighted the important role of distinct erosion and sediment transport processes, hydrologic connectivity, spatial and temporal patterns of rainfall, the occurrence of extreme events and the impacts of land use changes. The most effective ways and challenges to predict runoff, soil erosion and sediment yield at the catchment scale are also discussed.  相似文献   

Moisture transport and seasonal variations in the stable isotopic composition of rainfall in Central American and Andean Páramo during El Niño conditions (2015–2016)     

Germain Esquivel‐Hernndez  Giovanny M. Mosquera  Ricardo Snchez‐Murillo  Adolfo Quesada‐Romn  Christian Birkel  Patricio Crespo  Rolando Clleri  David Windhorst  Lutz Breuer  Jan Boll 《水文研究》2019,33(13):1802-1817

High‐elevation tropical grassland systems, called Páramo, provide essential ecosystem services such as water storage and supply for surrounding and lowland areas. Páramo systems are threatened by climate and land use changes. Rainfall generation processes and moisture transport pathways influencing precipitation in the Páramo are poorly understood but needed to estimate the impact of these changes, particularly during El Niño conditions, which largely affect hydrometeorological conditions in tropical regions. To fill this knowledge gap, we present a stable isotope analysis of rainfall samples collected on a daily to weekly basis between January 2015 and May 2016 during the strongest El Niño event recorded in history (2014–2016) in two Páramo regions of Central America (Chirripó, Costa Rica) and the northern Andes (Cajas, south Ecuador). Isotopic compositions were used to identify how rainfall generation processes (convective and orographic) change seasonally at each study site. Hybrid Single Particle Lagrangian Integrated Trajectory model (HYSPLIT) air mass back trajectory analysis was used to identify preferential moisture transport pathways to each Páramo site. Our results show the strong influence of north‐east trade winds to transport moisture from the Caribbean Sea to Chirripó and the South American low‐level jet to transport moisture from the Amazon forest to Cajas. These moisture contributions were also related to the formation of convective rainfall associated with the passage of the Intertropical Convergence Zone over Costa Rica and Ecuador during the wetter seasons and to orographic precipitation during the transition and drier seasons. Our findings provide essential baseline information for further research applications of water stable isotopes as tracers of rainfall generation processes and transport in the Páramo and other montane ecosystems in the tropics.  相似文献   

Simulation and properties of a non-homogeneous spring-block earthquake model with asperities   总被引：1，自引：0，他引：1  

Alejandro Muñoz-Diosdado  Adolfo H. Rudolf-Navarro  Fernando Angulo-Brown 《Acta Geophysica》2012,60(3):740-757

The spring-block model proposed by Olami, Feder and Christensen (OFC) has several properties that are similar to those observed in real seismicity. In this paper we propose a modification of the original model in order to take into account that in a real fault there are several regions with different properties (non-homogeneity). We define regions in the network that is reminiscent of the real seismic fault, with different sizes and elastic parameter values. We obtain the Gutenberg-Richter law for the synthetic earthquake distributions of magnitude and the stair-shaped plots for the cumulative seismicity. Again, as in the OFC-homogeneous case, we obtain the stability for the cumulative seismicity stair-shaped graphs in the long-term situation; this means that the straight line slopes that are superior bounds of the staircases have a behavior akin to the homogeneous case. We show that with this non-homogeneous OFC model it is possible to include the asperity concept to describe high-stress zones in the fault.  相似文献   

Analysis of soil surface component patterns affecting runoff generation. An example of methods applied to Mediterranean hillslopes in Alicante (Spain)   总被引：2，自引：1，他引：1  

E. Arnau-Rosaln  A. Calvo-Cases  C. Boix-Fayos  H. Lavee  P. Sarah 《Geomorphology》2008,101(4):595-606

Spatial patterns of soil surface components (vegetation, rock fragments, crusts, bedrock outcrops, etc.) are a key factor determining hydrological functioning of hillslopes. A methodological approach to analyse the patterns of soil surface components at a detailed scale is proposed in this paper. The methods proposed are applied to two contrasting semi-arid Mediterranean hillslopes, and the influence of soil surface component patterns on the runoff response of the slopes was analysed. A soil surface components map was derived from a high resolution photo-mosaic obtained in the field by means of a digital camera. Rainfall simulation experimental data were used to characterise the hydrological behaviour of areas with a specific pattern of soil surface components by means of the parameters of the Horton equation. Plot runoff data were extrapolated at the hillslope scale based on the soil surface component maps and their hydrological characterisation. The results show that in both slopes runoff generation is concentrated up- and downslope, with a water accepting area in the centre of both slopes disrupting the hydrological connectivity at the slope scale. This reinfiltration patch at the centre of the slope is related to the type of soil surface component and its spatial pattern. Herbaceous vegetation and ‘on top rock fragments’ increase the infiltration capacity of soils at the centre of the slope. In contrast, embedded rock fragments, rock outcrops, as well as crusted surfaces located in the upper and lower slopes favour runoff generation in these areas. In addition, a general pattern of water contribution areas downslope is apparent on both slopes. The south-facing slope shows a higher hydrological connectivity and more runoff. 55% of the surface of the south-facing slope produces runoff at the end of a 1 hour rainfall event and 17.3% of the surface is covered by a runoff depth between 0.5 and 1 mm. While on the north-facing slope only 38% of the surface produces runoff under the same conditions. Longitudinal connectivity of runoff is higher at the south-facing slope where more runoff-generating surfaces appear and where the vegetation pattern favours the connectivity of bare areas.  相似文献   

Symmetries and Bifurcations in the Sitnikov Problem     

Lidia Jiménez-Lara  Adolfo Escalona-Buendía 《Celestial Mechanics and Dynamical Astronomy》2001,79(2):97-117

We present some qualitative and numerical results of the Sitnikov problem, a special case of the three-body problem, which offers a great variety of motions as the non-integrable systems typically do. We study the symmetries of the problem and we use them as well as the stroboscopic Poincarée map (at the pericenter of the primaries) to calculate the symmetry lines and their dynamics when the parameter changes, obtaining information about the families of periodic orbits and their bifurcations in four revolutions of the primaries. We introduce the semimap to obtain the fundamental lines l ₁. The origin produces new families of periodic orbits, and we show the bifurcation diagrams in a wide interval of the eccentricity (0 0.97). A pattern of bifurcations was found.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

Robust smooth magneto tell uric transfer functions   总被引：3，自引：0，他引：3  

Jimmy C. Larsen    Randall L. Mackie    Adele Manzella    Adolfo Fiordelisi  Shirley Rieven 《Geophysical Journal International》1996,124(3):801-819

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Geochemistry of C₂₅ and C₃₀ biogenic alkenes in sediments of the narragansett bay estuary     

Adolfo G Requejo  James G Quinn 《Geochimica et cosmochimica acta》1983,47(6):1075-1090

The distributions of a series of structurally related C₂₅ and C₃₀ biogenic alkenes in sediments of the Narragansett Bay estuary have been determined. The suite of alkenes detected differs both quantitatively and qualitatively from those previously reported in other estuanne and coastal regions. Four C₂₅ mono- and dienes and one C₃₀ diene comprise 73–91% of the total alkenes in all surface (upper 2.5–5 cm) sediments analyzed. However, significant geographic variations exist in the relative abundance of these five compounds throughout the estuary. A comparison of alkene concentrations with δ¹³C of the bulk sedimentary organic matter has shown that the geographic variations of some alkenes reflect the distribution of marine organic matter, suggesting a marine source for these compounds. The distributions of other alkenes are not similarly correlated. In particular, concentrations of the C₃₀ diene are relatively constant and exhibit no dependence on the origin of organic matter in these sediments. This distribution implies an in situ production of this alkene throughout the estuary. Analysis of several sediment cores reveals that alkene concentrations are generally highest at the surface and decrease to low, constant values within the upper 25 cm. An exception is the subsurface concentration of one C₂₅ diene, which exhibits an increase at the same depth in two separate upper bay cores.  相似文献   

Bioturbation and erosion rates along the soil-hillslope conveyor belt,part 2: Quantification using an analytical solution of the diffusion–advection equation     

Andrea Román-Sánchez  Ana Laguna  Tony Reimann  Juan Vicente Giráldez  Adolfo Peña  Tom Vanwalleghem 《地球表面变化过程与地形》2019,44(10):2066-2080

Particles on soil-mantled hillslopes are subject to downslope transport by erosion processes and vertical mixing by bioturbation. Both are key processes for understanding landscape evolution and soil formation, and affect the functioning of the critical zone. We show here how the depth–age information, derived from feldspar-based single grain post-infrared infrared stimulated luminescence (pIRIR), can be used to simultaneously quantify erosion and bioturbation processes along a hillslope. In this study, we propose, for the first time, an analytical solution for the diffusion–advection equation to calculate the diffusivity constant and erosion–deposition rates. We have fitted this model to age–depth data derived from 15 soil samples from four soil profiles along a catena located under natural grassland in the Santa Clotilde Critical Zone Observatory, in the south of Spain. A global sensitivity analysis was used to assess the relative importance of each model parameter in the output. Finally, the posterior probability density functions were calculated to evaluate the uncertainty in the model parameter estimates. The results show that the diffusivity constant at the surface varies from 11.4 to 81.9 mm² a^-1 for the hilltop and hill-base profile, respectively, and between 7.4 and 64.8 mm² a^-1 at 50 cm depth. The uncertainty in the estimation of the erosion–deposition rates was found to be too high to make a reliable estimate, probably because erosion–deposition processes are much slower than bioturbation processes in this environment. This is confirmed by a global sensitivity analysis that shows how the most important parameters controlling the age–depth structure in this environment are the diffusivity constant and regolith depth. Finally, we have found a good agreement between the soil reworking rates proposed by earlier studies, considering only particle age and depth, and the estimated diffusivity constants. The soil reworking rates are effective rates, corrected for the proportion of particles actually participating in the process. © 2019 John Wiley & Sons, Ltd.  相似文献   

The Tesistan,Mexico earthquake (Mw 4.9) of 11 May 2016: seismic-tectonic environment and resonance vulnerability on buildings     

Alejandro Ramírez-Gaytán  Adolfo Preciado  William L. Bandy  Edilson F. Salazar-Monroy  Miguel A. Jaimes  Leonardo Alcantara 《地震工程与工程振动(英文版)》2019,18(3):579-595

To highlight the importance of small earthquakes in seismic hazard, a study of the 11 May 2016, M_w 4.9, Tesistan, Mexico earthquake is presented. Due to the close proximity of the event to the city, accelerations were considerably higher than those caused by historical severe earthquakes(6.0 M_w 8.2). This paper addresses two objectives related to the Tesistan event: the first is to estimate the focal mechanism solution in order to place the event in the context of the tectonic environment of this area. The second is focused on a vulnerability evaluation of buildings that suffered resonance. Several building′s typologies with variations in construction system and height are assessed in terms of resonance with the structural and soil periods. The results show that around the Zapopan station, strong damage is expected in intermediate to high-rise buildings(12-30 m) with moment resistant frame systems and in reinforced concrete shear walls. Masonry structures around this station may not present resonance. In contrast, in the surroundings of the Guadalajara station, all intermediate height buildings from 9 to 21 m may present resonance.  相似文献   

Las Cargas: Characterization and Prehistoric Use of a Southern Andean Obsidian Source     

Laura Salgn  Raven Garvey  Gustavo Neme  Adolfo Gil  Martín Giesso  Michael D. Glascock  Víctor Durn 《Geoarchaeology》2015,30(2):139-150

The importance of obsidian from the northern Patagonian source at Las Cargas is reflected in its early use (∼8000 years B.P.) and extensive geographic diffusion but is nonetheless surprising in light of the source's high altitude (located in the Andes Cordillera), which makes it both difficult to access under ideal conditions and inaccessible for much of the year. Prehistoric use of the Las Cargas source can inform us about mobility, subsistence choices, economics of stone consumption, trade, and territoriality. Here we present the results of various lines of evidence (surface survey, X‐ray fluorescence and instrumental neutron activation analyses, artifact morphometry, and obsidian hydration dating) used to characterize obsidian from Las Cargas and its prehistoric use during the Holocene. Results indicate that Las Cargas obsidian occurs at the source as blocks and nodules, which are chemically homogeneous and of variable quality. Use of the source was nearly continuous through time, and the primary knapping activities performed there were the production of blanks and preparation of cores.  相似文献