Estimation of Shelf-Slope Exchanges Induced by Frontal Instability Near Submarine Canyons

The dynamics associated with the propagation of unstable waves along a density front and their interaction with submarine canyons are simulated and analyzed with a fine-resolution three-dimensional primitive equation coastal ocean model. Simulations consider flow in an alongshore density front over two bottom topographies: an idealized straight shelf and a shelf incised by a canyon. The stationary circulation over the idealized shelf exhibits a geostrophic balance that is perturbed when the canyon topography is introduced. Enhanced cross-shore and vertical motions are produced as a result of the front-canyon interaction. A second set of simulations consider the effect of a small perturbation superimposed on the frontal circulation which develops growing meanders. In this case, the perturbation over the shelf grows rapidly by baroclinic instability into a steepened backward breaking wave characterized by significant cross-shore and vertical motions. The canyon topography accelerates or slows the development of the perturbation depending on the relative position of the unstable waves and the canyon. Finally, we use model results to determine the shelf-slope exchanges based on two methodologies. The first method computes the water transported across the shelf break while the second accounts for cross-shore displacements of water. The application of both approaches reveals that not all water transported across the shelf break is effectively exchanged between the shelf and the open ocean. However, cross-shore and vertical motions are enhanced by the unstable front and the submarine canyon leading to a large exchange between shelf and open ocean waters

Extreme Value Theory and the Solar Cycle

We investigate the statistical properties of the extreme events of the solar cycle as measured by the sunspot number. The recent advances in the methodology of the theory of extreme values is applied to the maximal extremes of the time series of sunspots. We focus on the extreme events that exceed a carefully chosen threshold and a generalized Pareto distribution is fitted to the tail of the empirical cumulative distribution. A maximum likelihood method is used to estimate the parameters of the generalized Pareto distribution and confidence levels are also given to the parameters. Due to the lack of an automatic procedure for selecting the threshold, we analyze the sensitivity of the fitted generalized Pareto distribution to the exact value of the threshold. According to the available data, that only spans the previous ~250 years, the cumulative distribution of the time series is bounded, yielding an upper limit of 324 for the sunspot number. We also estimate that the return value for each solar cycle is ~188, while the return value for a century increases to ~228. Finally, the results also indicate that the most probable return time for a large event like the maximum at solar cycle 19 happens once every ~700 years and that the probability of finding such a large event with a frequency smaller than ~50 years is very small. In spite of the essentially extrapolative character of these results, their statistical significance is very large.Comment: 6 pages, 4 figures, accepted for publication in A&

Photodiodes based in La0.7Sr0.3MnO3/single layer MoS2 hybrid vertical heterostructures

The fabrication of artificial materials by stacking of individual two-dimensional (2D) materials is amongst one of the most promising research avenues in the field of 2D materials. Moreover, this strategy to fabricate new man-made materials can be further extended by fabricating hybrid stacks between 2D materials and other functional materials with different dimensionality making the potential number of combinations almost infinite. Among all these possible combinations, mixing 2D materials with transition metal oxides can result especially useful because of the large amount of interesting physical phenomena displayed separately by these two material families. We present a hybrid device based on the stacking of a single layer MoS2 onto a lanthanum strontium manganite (La0.7Sr0.3MnO3) thin film, creating an atomically thin device. It shows a rectifying electrical transport with a ratio of 103, and a photovoltaic effect with Voc up to 0.4 V. The photodiode behaviour arises as a consequence of the different doping character of these two materials. This result paves the way towards combining the efforts of these two large materials science communities.Comment: 1 table, 4 figures (+9 supp. info. figures

Downscaling ECMWF seasonal precipitation forecasts in Europe using the RCA model

6 páginas, 4 figuras.--Licencia Creative Commons Reconocimiento-No comercial 3.0The operational performance and usefulness of regional climate models at seasonal time scales are assessed by downscaling an ensemble of global seasonal forecasts. The Rossby Centre RCA regional model was applied to downscale a five-member ensemble from the ECMWF System3 global model in the European Atlantic domain for the period 1981–2001. One month lead time global and regional precipitation predictions were compared over Europe—and particularly over Spain—focusing the study in SON (autumn) dry events. A robust tercile-based probabilistic validation approach was applied to compare the forecasts from global and regional models, obtaining significant skill in both cases, but over a wider area for the later. Finally, we also analyse the performance of a mixed ensemble combining both forecasts.This work was partly supported by projects ENSEMBLES from the 6th FP EU(GOCE-CT-2003-505539), EXTREMBLES (CGL2010-21869) and CORWES (CGL2010-22158-C02) from the Spanish Ministry MICINN (Plan Nacional de I+D+i) and by ESCENA (200800050084265) from the Spanish Ministry MARM.Peer reviewe

The roman pottery workshop of cartuja (granada). New data from the archaeological intervention developed in 2013-2015

La presente contribución ofrece nuevos datos so - bre el alfar romano de Cartuja (Granada), obtenidos durante el seguimiento arqueológico preventivo desarrollado en el Campus de Cartuja de la Universidad de Granada con motivo de su reciente reurbanización. La amplitud del seguimiento ha permitido documentar nuevas áreas productivas y estruc - turas, entre ellas dos nuevos hornos y piletas de decantación de arcillas, así como distintas áreas de vertidos. Basándose en estos datos, el presente artículo realiza una aproximación pre - liminar a su organización y topografía, en la que parece que existieron diversos sectores productivos lo suficientemente distanciados como para plantear un modelo de alfar subur - bano de organización diseminada.The aim of this paper is to present the last out - comes of the Roman pottery workshop of Cartuja (Granada), obtained from the archaeological intervention undertaken in connection with the recent improvements of the Cartuja cam - pus of the University of Granada. This intervention has ena - bled to report new functional workshop areas and structures, such as two new kilns and clay pools, and also different waste tip areas. Based on this data, this paper presents a prelimi - nary approach to the different productive areas organization and topography, where there were various productive sectors separated each other that belongs to a spread suburban pot - tery center

Las tabernae de Pollentia (Mallorca). Materiales figurados como manifestaciones apotropaicas, de religiosidad, y de representación durante el siglo III

A series of figurative materials found in commercial blocks around the forum of Pollentia in the 3rd century phase are herein presented. These materials, mainly small bronze sculptures, show different representation strategies and attraction of customers, but also certain religious and superstitious attitudes, and are therefore important indicators of the daily life and beliefs of the masses that inhabit these establishments.Se presentan una serie de materiales figurados recuperados en los niveles del siglo III d.C. en las tabernae estructuradas en insulae del entorno del foro de Pollentia. Estos materiales, principalmente esculturas exentas de pequeño formato, muestran distintas estrategias de representación y atracción de la clientela, pero también ciertas actitudes religiosas y supersticiosas, por lo que constituyen importantes indicadores sobre la vida cotidiana y el entramado de creencias de las clases populares que habitan estos establecimientos