Vertical structure and temporal evolution of an anticyclonic eddy in the Balearic Sea (western Mediterranean)

An anticyclonic eddy in the Balearic Sea (western Mediterranean) was described using data from a mooring line deployed at the northern slope of Mallorca Island at about 900 m deep. Its surface signature was investigated using sea surface height and sea surface temperature images. The eddy, which lasted around 1 month, modified the thermohaline characteristics and the currents of the entire water column. Levantine Intermediate Waters, usually resident in the region, were displaced by colder and fresher Western Mediterranean Intermediate Waters associated with the eddy. Along-slope main currents (toward NE) were completely reversed at 500 m and significantly deviated at 900 m. Interestingly, near-bottom velocities were found to be systematically larger than those at intermediate depths. Furthermore, during the eddy, velocities reached values up to 26 cm/s at the bottom, 5 times larger than the bottom average speed. The recurrence of the phenomenon was explored with an eddy detection tool applied to satellite observations. Results indicated that anticyclonic eddies are common structures in the Balearic Current. Key Points Study of the vertical structure of an eddy. Time evolution of the eddy. More common structures than it was thought. ©2013. American Geophysical Union. All Rights Reserved.Peer Reviewe

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

Tidal influence on high frequency harbor oscillations in a narrow entrance bay

High frequency sea level oscillations at Wells Harbor (Maine, Northeastern US), with periods in the range of several tens of minutes, display a tidally modulated response. During low tides, these sea level oscillations reach amplitudes of 10–20 cm, while during high tides they are significantly smaller. Wells Harbor is located in a low lying area with a tidal range of about 2 m and is connected to the open ocean through a narrow channel. Thus, the extent and depth of the bay significantly vary over a tidal cycle. This changing geometry determines both the resonant periods and the amplification factor of the bay. Numerical results confirm the link between observed variability and these specific topographic features. Results imply that when exceptionally energetic long waves reach the Wells Harbor entrance (as in the case of a tsunami or meteotsunami) the expected response will be significantly stronger during low tide than during high tide. Although mean sea level would be lower in the former case, the currents inside the bay would be stronger and potentially more dangerous. This tidally modulated response could be extrapolated to other sites with similar topographic characteristics. © 2014, Springer Science+Business Media Dordrecht.This work was partially performed within the NOAA/NWS project “Toward a meteotsunami warning system along the U.S. coastline (TMEWS),” Award No. NA11NWS4670005. The work of A. Amores has been funded by a JAE-PreDoc Grant from Consejo Superior de Investigaciones Científicas (CSIC) and co-funded by Programa Operativo FSE 2007–2013. M. Marcos acknowledges a “Ramon y Cajal” contract funded by the Spanish Ministry of EconomyPeer Reviewe

Vertical structure and temporal evolution of an anticyclonic eddy in the Balearic Sea (Western Mediterranean)

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

Temporal variability of hydrographic conditions around the Balearic Islands from two mooring lines

Póster presentado en la General Assembly 2011 de la European Geosciences Union (EGU), celebrada del 3 al 8 de abril de 2011 en Viena (Austria)Peer Reviewe

The influence of oceanographic scenarios on the population dynamics of demersal resources in the Western Mediterranean: Hypotesis for hake and red shrimp off Balearic Islands

We analysed the relationships between climatic indices, population parameters (abundance, recruitment and spawning stock) and catchability of hake and red shrimp in the trawl fishery off Balearic Islands (western Mediterranean

Forcing factors affecting sea level changes at the coast

We review the characteristics of sea level variability at the coast focussing on how it differs from the variability in the nearby deep ocean. Sea level variability occurs on all timescales, with processes at higher frequencies tending to have a larger magnitude at the coast due to resonance and other dynamics. In the case of some processes, such as the tides, the presence of the coast and the shallow waters of the shelves results in the processes being considerably more complex than offshore. However, ‘coastal variability’ should not always be considered as ‘short spatial scale variability’ but can be the result of signals transmitted along the coast from 1000s km away. Fortunately, thanks to tide gauges being necessarily located at the coast, many aspects of coastal sea level variability can be claimed to be better understood than those in the deep ocean. Nevertheless, certain aspects of coastal variability remain under-researched, including how changes in some processes (e.g., wave setup, river runoff) may have contributed to the historical mean sea level records obtained from tide gauges which are now used routinely in large-scale climate research

Source spectrum for the Algerian tsunami of 21 May 2003 estimated from coastal tide gauge data

On 21 May 2003 a submarine earthquake occurred near Algiers producing a tsunami that propagated northward and reached the Balearic Islands and the Levantine coast of the Iberian Peninsula within an hour. Despite that the generated tsunami was moderate, sea level variations inside certain harbors at the Balearic Islands were significant, producing severe damage to moored boats. Available tsunami records in the affected harbors are examined to estimate amplifications factors of arriving waves and spectral characteristics of the source. Comparison between background and tsunami oscillations at various sites allowed separation of the tsunami source properties from local topographic effects. The fundamental period of the reconstructed source spectrum is 21 min, which is in close agreement with that found by Alasset et al. (2006) based on modeling the tsunami initiation. Copyright 2009 by the American Geophysical Union.Peer Reviewe

Tsunamis vs meteotsunamis at the Balearic Islands

Comunicación presentada en la General Assembly 2010 de la European Geosciences Union (EGU), celebrada del 2 al 7 de mayo de 2010 en Viena (Austria)Peer Reviewe