The rissaga of 15 June 2006 in Ciutadella (Menorca), a meteorological tsunami

An extraordinary >rissaga> event (the local name for high-amplitude sea level oscillations) with 4-5 m of amplitude occurred on 15 June 2006 at Ciutadella (Menorca, Spain). In this paper we describe the rissaga event and propose that the meteorological mechanism responsible for it was an unusual pressure jump, associated with a convective squall line.Peer Reviewe

Uncertainty budget of Mediterranean storm surge projections for the XXIst Century

Trabajo presentado en la EGU General Assemby 2013, celebrada del 7 al 12 de abril de 2013 en Viena (Austria)Peer Reviewe

Comparison of Mediterranean sea level fields for the period 1961-2000 as given by a data reconstruction and a 3D model

Two Mediterranean sea level distributions spanning the last decades are examined. The first one is a reconstruction of sea level obtained by a reduced-space optimal interpolation applied to tide gauge and altimetry data. The second distribution is obtained from a 3D (baroclinic) regional circulation model. None of the two representations includes the mechanical atmospheric forcing. Results are presented for two different periods: 1993-2000 (for which altimetry data are available) and 1961-2000 (the longest period common to both distributions). The first period is examined as a test period for the model, since the reconstruction is very similar to altimetry observations. The modelled sea level is in fair agreement with the reconstruction in the Western Mediterranean and in the Aegean Sea (except in the early nineties), but in the Ionian Sea the model departs from observations. For the whole period 1961-2000 the main feature is a marked positive trend in the Ionian Sea (up to 1.8 mm yr- 1), observed both in the reconstruction and in the model. Also the distribution of positive trends in the Western Mediterranean (mean value of 1.1 mm yr- 1) and the smaller trends in the Aegean Sea (0.5 mm yr- 1) are similar in the reconstruction and in the model, despite the first implicitly accounts for sea level variations due to remote sources such as ice melting and the second does not. The interannual sea level variability associated with key regional events such as the Eastern Mediterranean Transient is apparently captured by the reconstruction but not by the model (at least in its present configuration). Hence, the reconstruction can be envisaged as a useful tool to validate further long-term numerical simulations in the region. © 2009 Elsevier B.V. All rights reserved.Peer Reviewe

On the freshening of the northwestern Weddell Sea continental shelf

12 páginas, 10 figuras, 2 tablas.We analyzed hydrographic data from the northwestern Weddell Sea continental shelf of the three austral winters 1989, 1997, and 2006 and two summers following the last winter cruise. During summer a thermal front exists at ~64° S separating cold southern waters from warm northern waters that have similar characteristics as the deep waters of the central basin of the Bransfield Strait. In winter, the whole continental shelf exhibits southern characteristics with high Neon (Ne) concentrations, indicating a significant input of glacial melt water. The comparison of the winter data from the shallow shelf off the tip of the Antarctic Peninsula, spanning a period of 17 yr, shows a salinity decrease of 0.09 for the whole water column, which has a residence time of <1 yr. We interpret this freshening as being caused by a combination of reduced salt input due to a southward sea ice retreat and higher precipitation during the late 20th century on the western Weddell Sea continental shelf. However, less salinification might also result from a delicate interplay between enhanced salt input due to sea ice formation in coastal areas formerly occupied by Larsen A and B ice shelves and increased Larsen C ice loss.Una parte de la financiación de esta investigación se debe a los proyectos ATOS (POL2006-00550/CTM) y ESASSI (POL2006-11139-C02-01/CGL), subvencionados por el Subprograma de Investigación Polar del Ministerio de Ciencia e Innovación y el por el Fondo Europeo de Desarrollo Regional de la Unión Europea.Peer reviewe

Atmospheric contribution to Mediterranean and nearby Atlantic sea level variability under different climate change scenarios

The contribution of atmospheric pressure and wind to the XXI century sea level variability in Southern Europe is explored under different climate change scenarios. The barotropic version of the HAMSOM model is forced with the output of the atmospheric ARPEGE model run under scenarios B1, A1B and A2. Additionally, a control simulation forced by observed SST, GHGs and aerosols concentrations for the period 1950-2000 and a hindcast forced by a dynamical downscalling of ERA40 for the period 1958-2001 are also run using the same models. The hindcast results have been validated against tide gauge observations showing good agreement with correlations around 0.8 and root mean square error of 3.2. cm. A careful comparison between the control simulation and the hindcast shows a reasonably good agreement between both runs in statistical terms, which points towards the reliability of the modelling system when it is forced only by GHG and aerosols concentrations. The results for the XXI century indicate a sea level decrease that would be especially strong in winter, with trends of up to - 0.8 ± 0.1. mm/year in the central Mediterranean under the A2 scenario. Trends in summer are small but positive (~. 0.05 ± 0.04. mm/yr), then leading to an increase in the amplitude of the seasonal cycle. The interannual variability also shows some changes, the most important being a widespread standard deviation increase of up to 40%. An increase in the frequency of positive phases of the NAO explains part of the winter negative trends. Also, an increase in the NAO variability would be responsible for the projected increase of the interannual variability of the atmospheric component of sea level. Conversely, the intra-annual variability (1-12. months excluding the seasonal cycle) does not show significant changes. © 2011 Elsevier B.V.This work has been carried out in the framework of the projects VANIMEDAT-2 (CTM2009-10163-C02-01, funded by the Spanish Marine Science and Technology Program and the E-Plan of the Spanish Government) and ESCENARIOS (funded by the Agencia Estatal de METeorología). Additional funding from the Platja de Palma Consortium is also acknowledged. G. Jordà acknowledges a “JAE-DOC” contract funded by the Spanish Research Council (CSIC).Peer Reviewe

Características hidrodinámicas estacionales sobre la plataforma continental de Colima (costa oeste de México)

Four high-resolution hydrographic surveys were carried out in 2002 on the continental shelf of Colima, Pacific coast of Mexico. The data collected revealed the presence of cyclonic and anticyclonic eddy-like features covering the whole extension of the shelf, which is a rather different pattern from the along-shore general circulation described in previous works. Despite the apparent complexity of the circulation features, the overall shelf-slope exchange pattern is similar in autumn and winter and the opposite in spring. In summer the exchanges also have a similar distribution to autumn and winter, but they are restricted to the upper layers. This suggests that the observed circulation features could result from the interaction between the large-scale seasonal circulation and some kind of local forcing.Cuatro estudios hidrográficos de alta resolución fueron realizados en 2002 sobre la plataforma continental de Colima, costa del Pacífico de México. Los datos obtenidos muestran la presencia de remolinos y meandros ciclónicos y anticiclónicos extendiéndose sobre toda la plataforma, lo cual difiere de la circulación general a lo largo de la costa descrita en estudios anteriores. A pesar de la aparente complejidad de la circulación, la distribución de los intercambios entre plataforma y talud es similar en otoño e invierno, y opuesta en primavera. En verano el intercambio también tiene una distribución similar a otoño e invierno, pero ésta se restringe a las capas más superficiales. Parece, por tanto, que las características de la circulación pueden resultar de la interacción del flujo estacional de macro-escala con algún tipo de forzamiento local.