On the design of beach nourishment projects using static equilibrium concepts: Application to the Spanish coast     

Mauricio González  Raul Medina  Miguel Losada 《Coastal Engineering》2010

The concept of equilibrium plan form and equilibrium profile has been widely used as an engineering tool in order to design beach nourishment projects. The scope of this paper is to further explore this “equilibrium beach” concept in crenulated bays, as a long-term tool for beach nourishment projects. The proposed methodology is based on González and Medina (2001) and combines the static equilibrium plan and profile for long-term analysis. This methodology includes a modified equilibrium plan form, which is able to define the orientation of the local wave front in the diffracting point, and also to locate the downcoast starting point of the static equilibrium beach from which the parabolic plan form of Hsu and Evans (1989) is valid. This methodology permits the application of any equilibrium profile formulation. An example of the application of this methodology and long-term formulations to the design of the Spanish nourishment project of Poniente Beach (Gijón) is presented. Ten years after its construction, the beach has still got a static equilibrium and remains pretty close to the predicted equilibrium beach in plan and profile.  相似文献   

A new global landslide dam database (RAGLAD) and analysis utilizing auxiliary global fluvial datasets     

Wu  Hang  Trigg  Mark A.  Murphy  William  Fuentes  Raul 《Landslides》2022,19(3):555-572

To address the current data and understanding knowledge gap in landslide dam inventories related to geomorphological parameters, a new global-scale landslide dam dataset named River Augmented Global Landslide Dams (RAGLAD) was created. RAGLAD is a collection of landslide dam records from multiple data sources published in various languages and many of these records we have been able to precisely geolocate. In total, 779 landslide dam records were compiled from 34 countries/regions. The spatial distribution, time trend, triggers, and geomorphological characteristic of the landslides and catchments where landslide dams formed are summarized. The relationships between geomorphological characteristics for landslides that form river dams are discussed and compared with those of landslides more generally. Additionally, a potential threshold for landslide dam formation is proposed, based on the relationship of landslide volume to river width. Our findings from our analysis of the value of the use of additional fluvial datasets to augment the database parameters indicate that they can be applied as a reliable supplemental data source, when the landslide dam records were accurately and precisely geolocated, although location precision in smaller river catchment areas can result in some uncertainty at this scale. This newly collected and supplemented dataset will allow the analysis and development of new relationships between landslides located near rivers and their actual propensity to block those particular rivers based on their geomorphology.

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The EPIC atmospheric model with an isentropic/terrain-following hybrid vertical coordinate     

Timothy E. Dowling  Mary E. Bradley  John Kramer  Grace C.H. Lee  Raul Morales-Juberías  Vimal K. Parimi 《Icarus》2006,182(1):259-273

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Simulations of high-latitude spots on Jupiter: Constraints on vortex strength and the deep wind     

Raul Morales-Juberias  Timothy E. Dowling 《Planetary and Space Science》2005,53(12):1221-1233

We combine high-resolution observations of the dynamical behavior of small vortices (diameters ?5000 km) located at latitude 60°N on Jupiter with forward modeling, using the EPIC atmospheric model, to address two open questions: the dependence of the zonal winds with depth, and the strength of vortices that are too small to apply cloud tracking to their internal structure. The observed drift rates of the vortices can only be reproduced in the model when the zonal winds increase slightly with depth below the cloud tops, with a vertical shear that is less than was measured at 7°N at the southern rim of a 5-μm hotspot by the Galileo Probe Doppler Wind Experiment (DWE). This supports the idea that Jupiter's vertical shear may vary significantly with latitude. Our simulations suggest that the morphology of the mergers between vortices mainly depends on their maximum tangential velocities, the best results occurring when the tangential velocity is close to the velocity difference of the alternating jets constraining the zone in which the vortices are embedded. We use this correlation, together with the high-resolution data available for the White Ovals, to derive an empirical relationship between the maximum tangential velocity of a jovian vortex and its size, normalized by the strength and size of the encompassing shear zone. The Great Red Spot stands out as a significant anomaly to this relationship, but interestingly it is becoming less so with time.  相似文献   

SCALING TECHNIQUES IN THE ANALYSIS OF ENVIRONMENTAL COGNITION DATA *     

J. Raul Maga  Gary W. Evans  A. Kimball Romney 《The Professional geographer》1981,33(3):294-301

The utility of nonmetric, multidimensional-scaling techniques is demonstrated for the analysis and collection of environmental-cognition data. By comparing the multidimensional-scaling solutions of a real-setting map to scaling solutions for sketch maps and two psychophysical, distance-scaling procedures, we demonstrate that magnitude estimation of actual interpoint distances is comparable in accuracy to sketch maps when produced without constraints, or when subjects are given a specified list of landmarks to include on their maps. Triadic comparisons of actual interpoint distances were less accurate than the three other techniques.  相似文献   

Integrated water resource management in a major canal command in eastern India     

S. K. Raul  Sudhindra N. Panda  H. Holländer  M. Billib 《水文研究》2011,25(16):2551-2562

The present rice‐dominated cropping system in the Hirakud canal command (eastern India) is under severe threat due to imbalance between irrigation water supply and demand. The canal water supply, which is the only source of irrigation, only meets 54% of the demand at 90% probability of exceedance (PE). In order to mitigate the irrigation water deficit from canal water, groundwater is considered as a supplemental source. Quasi‐three‐dimensional groundwater flow simulation modelling was, therefore, carried out by using Visual MODFLOW to detect the change in hydraulic head due to transient pumping stresses. The simulation model was calibrated and validated satisfactorily. Sensitivity analysis of the model parameters shows that groundwater recharge is most sensitive followed by aquifer hydraulic conductivity at almost all the sites of the command area, whereas the model is comparatively less sensitive to specific storage and specific yield. Enhanced pumping scenarios showed that groundwater extraction can be increased up to 50 times of the existing pumping without causing any adverse effect to the aquifer but the aquifer does not permit to exploit water in order to fulfill the irrigation water demand even at 10% PE. Hence, it is imperative to develop an optimal land and water resources management plan of the command area. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Analysis of clustering and selection algorithms for the study of multivariate wave climate     

Paula Camus  Fernando J. Mendez  Raul Medina  Antonio S. Cofiño 《Coastal Engineering》2011

Recent wave reanalysis databases require the application of techniques capable of managing huge amounts of information. In this paper, several clustering and selection algorithms: K-Means (KMA), self-organizing maps (SOM) and Maximum Dissimilarity (MDA) have been applied to analyze trivariate hourly time series of met-ocean parameters (significant wave height, mean period, and mean wave direction). A methodology has been developed to apply the aforementioned techniques to wave climate analysis, which implies data pre-processing and slight modifications in the algorithms. Results show that: a) the SOM classifies the wave climate in the relevant “wave types” projected in a bidimensional lattice, providing an easy visualization and probabilistic multidimensional analysis; b) the KMA technique correctly represents the average wave climate and can be used in several coastal applications such as longshore drift or harbor agitation; c) the MDA algorithm allows selecting a representative subset of the wave climate diversity quite suitable to be implemented in a nearshore propagation methodology.  相似文献   

Preface to the Special Issue on Antarctic Meteorology and Climate:Past,Present and Future     

Jiping LIU  David BROMWICH  Dake CHEN  Raul CORDERO  Thomas JUNG  Marilyn RAPHAEL  John TURNER  Qinghua YANG 《大气科学进展》2020,37(5):421-422

The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth system.Research in Antarctic meteorology and climate has always been a challenging endeavor.Studying and predicting weather patterns in the Antarctic are important for understanding their role in local-to-global processes and facilitating field studies and logistical operations in the Antarctic(e.g.,Walsh et al.,2018).Studies of climate change in the Antarctic are comparatively neglected compared to those of the Arctic.However,significant climate changes have occurred in the Antarctic in the past several decades,i.e.,a strong warming over the Antarctic Peninsula even with a recent minor cooling,a deepening of the Amundsen Sea low,a rapid warming of the upper ocean north of the circumpolar current,an increase of Antarctic sea ice since the late 1970s followed by a recent rapid decrease,and an accelerated ice loss from the Antarctic ice shelf/sheet since the late 1970s(e.g.,Turner et al.,2005;Raphael et al.,2016;Sallée,2018;Parkinson,2019;Rignot et al.,2019).Investigating recent climate change in the Antarctic and the underlying mechanisms are important for predicting future climate change and providing information to policymakers.  相似文献   

Fast identification of transits from light-curves     

Pavlos Protopapas  Raul Jimenez  Charles Alcock 《Monthly notices of the Royal Astronomical Society》2005,362(2):460-468

We present an algorithm that allows fast and efficient detection of transits, including planetary transits, from light-curves. The method is based on building an ensemble of fiducial models and compressing the data using the moped compression algorithm. We describe the method and demonstrate its efficiency by finding planet-like transits in simulated Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) light-curves. We show that our method is independent of the size of the search space of transit parameters. In large sets of light-curves, we achieve speed-up factors of the order of 10³ times over an optimized adaptive search in the χ² space. We discuss how the algorithm can be used in forthcoming large surveys like Pan-STARRS and the Large Synoptic Survey Telescope (LSST), and how it may be optimized for future space missions like Kepler and COROT where most of the processing must be done on board.  相似文献   

Synthetic stellar populations: single stellar populations, stellar interior models and primordial protogalaxies     

Raul Jimenez  James MacDonald  James S. Dunlop  Paolo Padoan  John A. Peacock 《Monthly notices of the Royal Astronomical Society》2004,349(1):240-254

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