Comparison of several geoid models over the western Mediterranean sea

The Mediterranean Sea is a semi-enclosed true ocean. Recent Mediterranean circulation and sea level studies using various observations and ocean general circulation models show good coherence and agreement.Postprint (published version

Multi-satellite altimetry and GOCE geoid based surface and subsurface currents in the Mediterranean Sea

Peer ReviewedPostprint (published version

Geodèsia física

Descripció del recurs: 23 de setembre de 2015El llibre pretén proporcionar a l'alumne una visió bàsica i multidisciplinària sobre la Geodèsia Física. És una Geociència fonamental que utilitza un ampli ventall d'observacions terrestres, marines i espacials que contribueixen al coneixement del sistema Terra, la seva dinàmica i interaccions. Es presenta el camp gravitatori estàtic (distribució de masses, geoide) i variable (transport de masses, especialment el cicle de l'aigua). Es descriuen les noves tècniques geodèsiques com el monitoratge oceànic (satèl·lits radar i làser altimètrics), monitorització per teledetecció i mesures de la gravetat (LAGEOS, GRACE i GOCE). Finalment s'exposa la implementació del sistema GGOS (Global Geodetic Observing System) i les seves principals tècniques associades: VLBI, SLR, GNSS i DORIS

SAR measurements of coastal features in the NW Mediterranean

Peer ReviewedPostprint (published version

Ocean classification of dynamical structures detected by SAR and spectral methods

We discuss a taxonomy of different dynamical featuresin the ocean surface and provide some eddy and frontstatistics, as well as describing some events detected byseveral satellites and even with additional cruise observationsand measurements, in the North-west MediterraneanSea area between 1996 and 2012. The structureof the flows are presented using self-similar traces thatmay be used to parametrize mixing at both limits of the Ross by Deformation Radius scale, RL. Results showthe ability to identify different SAR signatures and at thesame time provide calibrations for the different local configurationsof vortices, spirals, Langmuir cells, oil spillsand tensioactive slicks that eventually allow the study ofthe self-similar structure of the turbulence. Dependingon the surface wind and wave level, and also on the fetch.the bathimetry, the spiral parameters and the resolution of vortical features change. Previous descriptions did not includethe new wind and buoyancy features. SAR imagesalso show the turbulence structure of the coastal area andthe Regions of Fresh Water Influence (ROFI). It is not eworthytt such complex coastal fielddependent behavioris strongly influenced by stratification and rotation of theturbulence spectrum is observed only in the range smallerthan the local Ross by deformation radius, RL. The measuresof diffusivity from buoy or tracer experiments areused to calibrate the behavior of different tracers and pollutants,both natural and man-made in the NW MediterraneanSea. Thanks to different polarization and intensitylevels in ASAR satellite imagery, these can be usedto distinguish between natural and man-made sea surfacefeatures due to their distinct self-similar and fractal as afunction of spill and slick parameters, environmental conditionsand history of both oil releases and weather conditions.Eddy diffusivity map derived from SAR measurementsof the ocean surface, performing a feature spatialcorrelation of the available images of the region are presented.Both the multi fractal discrimination of the localfeatures and the diffusivity measurements are importantto evaluate the state of the environment. The distributionof meso-scale vortices of size, the Ross by de for mationscale and other dominant features can be used to distinguishfeatures in the ocean surface. Multi-fractal analysisis then very use full. The SAR images exhibited a largevariation of natural features produced by winds, internalwaves, the bathymetric distribution, by convection, rain,etc as all of these produce variations in the sea surfaceroughness so that the topological changes may be studiedand classified. In a similar way bathimetry may bestudied with the methodology described here using thecoastline and the thal wegs as generators of local verticalvorticity.Peer ReviewedPreprin

Monitoring sea level by tide gauges and GPS at Barcelona and Estartit harbours

The presentation is directed to the description of the actual situation of the geodetic infrastructure of Barcelona and l’Estartit sites for sea level determination and contribution to regional sea level risePostprint (published version

Competing misfit relaxation mechanisms in epitaxial correlated oxides

Strain engineering of functional properties in epitaxial thin films of strongly correlated oxides exhibiting octahedral-framework structures is hindered by the lack of adequate misfit relaxation models. Here we present unreported experimental evidence of a four-stage hierarchical development of octahedral-framework perturbations resulting from a progressive imbalance between electronic, elastic, and octahedral tilting energies in La 0.7Sr0.3MnO3 epitaxial thin films grown on SrTiO3 substrates. Electronic softening of the Mn-O bonds near the substrate leads to the formation of an interfacial layer clamped to the substrate with strongly degraded magnetotransport properties, i.e., the so-called dead layer, while rigid octahedral tilts become relevant at advanced growth stages without significant effects on charge transport and magnetic orderin

Experiences on altimeter calibration at Ibiza island and Cape of Begur (Spain)

Three preliminary camp aigns for TOPEX /POSEIDON (T/P) wer e made in March 1999 and July 2000 and for JASON-1 in August 2002, in the NW Mediterran ean Sea at th e Begur Cape area. Dir ect abso lute altimeter calibration , and mapping of the sea surface, w ere made in these camp aigns from dir ect overflights using GPS buoys with a toroidal design performed at the I CC based in the orig inal design of the Univ ersity of Colorado at Boulder and a estimation of the TOPEX A lt- B bias w as made. A Spanish JASON-1 geoid gradien t campaign with Fench support has been made in June 2003 at the Ibiza island in the NW Mediterr anean Sea. Th e main objectiv e has b een to map w ith a new d esign ed, builded and calibrated GPS catamar an, the lo cal geoid gradien t in three ar eas around Ibiza island under the ascending (187) and descending (248) Jason-1ground tracks. The catamaran equ ipped with two GPS antennas to perform continuous sea lev el measur ements was towed by the Patro l Dev a from th e Span ish N avy. Five GPS reference stations were dep loyed on Ibiza island: one in Portinatx, two in San Anton io and two in Ibiza. The marin e geo id has been used to relate the coastal tide gauge data from Ibiza and San An tonio h arbours to off- shore altimetric data. In th e framework of the campaign, the levelling of the Ibiza and San Anton io tide gauges to the r espective GPS mark ers w as p erformed. We present synth esis of the resu lts obtained from Topex/Poseidon and th e first r esults on Jason-1 altimeter calibration using the direct measurements from GPS buoys and the derived marin e geoid. Th e Ibiza results agree relativ ely w ell with resu lts ob tained at Corsica, Harvest and Bass Strait calibration permanen t sites. Moreov er, the geod etic activities (e.g., GPS, levelling) has p ermitted to build a very accurate (few mm) local n etwork link ed to th e European one, w ith a reference frame compatible with th e satellite altimetry missions (ITRF2000). The GPS kinematic data wer e processed using two d ifferen t sof twar es allowing to check th e consistency of the solutions. A perspective of a new Jason-1, in cluding Envisat, Ibiza campaign to be made around 2007 will be pr esen ted. These camp aigns w ere supporte by th e Span ish Ministery of Scien ce and Technology under projects of the N ational Space Program ref : ESP1997-1816-CO4- 03 and ESP2001-4534-PE.Peer ReviewedPostprint (published version

Molecular phylogeny of the genus Chondrina (Gastropoda, Panpulmonata, Chondrinidae) in the Iberian Peninsula

[EN] Chondrina Reichenbach, 1828 is a highly diverse genus of terrestrial molluscs currently including 44 species with about 28 subspecific taxa. It is distributed through North Africa, central and southern Europe, from Portugal in the West to the Caucasus and Asia Minor in the East. Approximately 70% of the species are endemic to the Iberian Peninsula constituting its main center of speciation with 34 species. This genus includes many micro endemic taxa, some of them not yet described, confined to limestone habitats (being strictly rock-dwelling species). They are distributed on rocky outcrops up to 2000 m.a.s.l. It is a genus of conical-fusiform snails that differ mainly in shell characters and in the number and position of teeth in their aperture. So far, molecular studies on Chondrina have been based exclusively on the mitochondrial Cytochrome Oxidase subunit I region (COI). These studies gave a first view of the phylogeny of the genus but many inner nodes were not statistically supported. The main objective of the study is to obtain a better understanding of the phylogeny and systematics of the genus Chondrina on the Iberian Peninsula, using multilocus molecular analysis. Partial sequences of the COI and 16S rRNA genes, as well as of the nuclear Internal Transcribed Spacer 1 (ITS1-5.8S) and Internal Transcribed Spacer 2 (5.8S-ITS2-28S) were obtained from individuals of all the extant Chondrina species known from the Iberian Peninsula. In addition to this, the newly obtained COI sequences were combined with those previously published in the GenBank. Phylogenetic relationships were inferred using maximum likelihood and Bayesian methods. The reconstructed phylogenies showed high values of support for more recent branches and basal nodes. Moreover, molecular species delimitation allowed to better define the studied species and check the presence of new taxa.This work was partially funded by the Basque Government through the Research group on “Systematics, Biogeography and Population Dynamics” (IT575-13) and “Systematics, Biogeography, Behavioural ecology and Evolution” (IT1163-19). E. Somoza Valdeolmillos was supported by a PhD fellowship awarded in 2015 by the University of the Basque Country (UPV/EHU)

Influence of Incidence Angle in the Correlation of C-band Polarimetric Parameters with Biophysical Variables of Rain-fed Crops

A multi-temporal field experiment was conducted within the Soil Measurement Stations Network of the University of Salamanca (REMEDHUS) in Spain in order to retrieve useful crop information. The objective of this research was to evaluate the potential of polarimetric observations for crop monitoring by exploiting a time series of 20 quad-pol RADARSAT-2 images at different incidence angles (i.e. 25°, 31°, and 36°) during an entire growing season of rain-fed crops, from February to July 2015. The time evolution of 6 crop biophysical variables was gathered from the field measurements, whereas 10 polarimetric parameters were derived from the images. Thus, a subsequent correlation analysis between both datasets was performed. The study demonstrates that the backscattering ratios (HH/VV and HV/VV), the normalized correlation between HH and VV (γHHVV), and the dominant alpha angle (α1), showed significant and relevant correlations with several biophysical variables such as biomass, height, or leaf area index (LAI) at incidence angles of 31° or 36°. The joint use of data acquired with different beams could be exploited effectively to increase the refresh rate of information about crop condition with respect to a single incidence acquisition scheme.This study was supported by the Spanish Ministry of Economy and Competitiveness and the Spanish Ministry of Science, Innovation and Universities, [Projects ESP2015-67549-C3-3, ESP2017-89463-C3-3-R, and TEC2017-85244-C2-1-P] and the European Regional Development Fund (FEDER)