Examining the constructs about the supervisor\u27s difficulty scale in supporting the return to work of people with mental health disorders

Within the framework of the multidisciplinary RECS project and with the aim of describing the particle flux transfer from the continental shelf to the deep basin, an array of five mooring lines equipped with a total of five pairs of PPS3/3 sequential-sampling sediment traps and RCM-7/8 current meters were deployed 30 m above the bottom from March 2003 to March 2004 inside and outside the Blanes Canyon. One mooring line was located in the upper canyon at 600 m depth, one in the canyon axis at 1700 m depth and other two close to the canyon walls at 900 m depth. A fifth mooring line was deployed in the continental open slope at 1500 m water depth. The highest near-bottomdownwardparticle flux (14.50 g m-2 d-1)wasrecorded at the trap located in the upper canyon (M1), where continental inputs associated with the presence of the Tordera River are most relevant. On the other hand, the downward fluxes (4.35 g m-2 d-1) in the canyon axis (M2) were of the same order as those found in the western flank (M3) of the canyon. Both values were clearly higher than the value (1.95 g m-2 d-1) recorded at the eastern canyon wall (M4). The open slope (M5) mass flux (5.42 mg m-2 d-1) recorded by the sediment trap located outside the canyon system was three orders of magnitude lower than the other values registered by the inner canyon stations. The relevance of our data is that it explains how the transport pathway in the canyon occurs through its western flank, where a more active and persistent current toward the open ocean was recorded over the entire year of the experiment. Off-shelf sediment transport along the canyon axis showed clear differences during the period of the study, with some important events leading to strong intensifications of the current coupled with large transport of particle fluxes to the deepest parts of the canyon. Such events are primarily related to increases in river discharge and the occurrence of strong storms and cascading events during the winter. In summary, in this study it is shown that the dynamics of thewater masses and the currents in the study area convert the sharp western flank of the Blanes Canyon in a more active region that favors erosion processes than the eastern flank, which has a smoother topography and where the absence of erosional conditions yields to steadier sedimentary processes.Peer ReviewedPostprint (published version

Mesoscale variability of the northern current in the gulf of lions and the role of bottom topography

The Northern Current flows cyclonically contouring the continental slope in the NW Mediterranean. At the entrance of the Gulf of Lions this current is about 20 -- 30 km wide and flows along the deepest half of the continental slope, i.e. over the 1000 to 2000 m isobaths approximately. Surface speeds are of 30 -- 50 cm s^{-1}. In the MATER HFF experiment (March -- May 1997) mesoscale variability of the Northern Current is observed from current meter records, SST images and hydrographic data. The HFF experimental box is 20 x 40 km, covering the upper half of the slope (i.e. covering from 250 m to 1250 m depth isobaths). Current meter and satellite data show that the site is embedded in a region of significant Northern Current meandering and eddy activity. From SST images, meander wavelengths are estimated larger than 60 km, embracing smaller structures. These flow patterns affect upper-layer waters down to at least 650 m depth. Current meter data distinguish two narrow energetic bands centred at 3.5 days and 7.5 days, respectively, in agreement with previous studies.Baroclinic instability is viewed as a possible mechanism to explain the generation of the Northern Current meanders. The analytical model of Tang (1975) predicts the development of unstable waves of wavelength (> 60 km) and periods compatible with the 7.5 day band recorded with current meter devices. The higher frequency band of 3.5 days is out of the frequency range predicted by the classical baroclinic instability theory and it is discussed as a restriction of quasi-geostrophic theory.Barotropic instability is studied using a laboratory model of a -westward' jet flowing over the lower half of the continental slope, which considers dynamic similarity with the Northern Current. The laboratory model is cross-validated with a corresponding numerical model. Jet instabilities of currents similar to the Northern Current (i.e. westward jets) occur at the edges of the jet, showing a clear meandering tendency over the mid-slope. Westward currents of Ro = 0.1 -- 0.2 develop instabilities of wavelengths (50 -- 75 km) similar to those observed from SST images, with periods (3.3 -- 3.8 days) compatible with the 3.5 days period band recorded with HFFE current meters.The laboratory and numerical experiments have reproduced westward jets (as the Northern Current), but also eastward jets, in order to have a full approach to better understand the role of the bottom topography on barotropic instabilities. The slope current instabilities are successfully explained by the Marcus and Lee theory (1998) of jets on a beta plane. This theory is valid for westward flows with Ro > 0.1 and for eastward flows with Ro > 0.2 (jets of the so-called Regime II flows in this thesis), and it states that the instabilities of each shear layer of the barotropic jet take the appearance of a Kelvin-Helmholtz-like pattern, associated with a Rossby wave (of topographic origin in our case). According to this theory, the differences between eastward and westward jets rely on the disposition of the Rossby waves --at the centre of the current in eastward flows and at the edges of the jet in westward currents. Jets over a sloping bottom with small Rossby numbers (Ro The differences between eastward and westward slope currents observed in this work (and similar observations of jets on a beta-plane from previous works) are explained in this thesis by a simple scheme based on conservation of potential vorticity, considering there are two main components in balance: the shear-induced vorticity and the topographically induced vorticity. The signs of these two components are determined by the relative direction of the flow with respect to the inclination of the bottom topography. Once the critical Rossby number is overpassed so that the topographic effects are important (Ro > 0.1 for westward jets; Ro > 0.2 for eastward jets), conservation of potential vorticity tends to enhance vortices at the centre of eastward jets --eastward jets show meandering at the jet core. In westward jets, potential vorticity conservation is responsible of enhancing vortices at each edge of the jet. Thus, westward jets (as the Northern Current) are broad and meandering occurs at the jet edges.In Ro > 0.1 westward flows (i.e. Regime II westward jets) a topographic Rossby wave appears over the shelf break. This result is likely observed because of the specific topography used in this work --a continental slope and a continental shelf separated by a shelf break, producing a strong change in ambient potential vorticity. Numerical simulations reveal that this Rossby wave is triggered by the slope current. This topographic Rossby wave is a robust pattern, since it is independent of the position of the current over the slope, the shape of the velocity shear profile of the jet, and the jet width. Although this type of wave could not be inferred from the HFFE field data, it could be a focus of study in further field experiments. It also needs further analytical consideration. The general conclusion extracted from this thesis that tries to explain the mesoscale variability associated to the Northern Current is that both baroclinic and barotropic instability could explain part of the oceanic observations. As a consequence, mixed barotropic-baroclinic instability (which occurs at wavelengths which are between those corresponding to pure barotropic and pure baroclinic instability) is thought to play an important role on the observed mesoscale variability. The resulting wavelength would depend on the relative strength of both mechanisms

Particle fluxes dynamics in Blanes submarine canyon (Northwestern Mediterranean)

Within the framework of the multidisciplinary RECS project and with the aim of describing the particle flux transfer from the continental shelf to the deep basin, an array of five mooring lines equipped with a total of five pairs of PPS3/3 sequential-sampling sediment traps and RCM-7/8 current meters were deployed 30 m above the bottom from March 2003 to March 2004 inside and outside the Blanes Canyon. One mooring line was located in the upper canyon at 600 m depth, one in the canyon axis at 1700 m depth and other two close to the canyon walls at 900 m depth. A fifth mooring line was deployed in the continental open slope at 1500 m water depth. The highest near-bottomdownwardparticle flux (14.50 g m-2 d-1)wasrecorded at the trap located in the upper canyon (M1), where continental inputs associated with the presence of the Tordera River are most relevant. On the other hand, the downward fluxes (4.35 g m-2 d-1) in the canyon axis (M2) were of the same order as those found in the western flank (M3) of the canyon. Both values were clearly higher than the value (1.95 g m-2 d-1) recorded at the eastern canyon wall (M4). The open slope (M5) mass flux (5.42 mg m-2 d-1) recorded by the sediment trap located outside the canyon system was three orders of magnitude lower than the other values registered by the inner canyon stations. The relevance of our data is that it explains how the transport pathway in the canyon occurs through its western flank, where a more active and persistent current toward the open ocean was recorded over the entire year of the experiment. Off-shelf sediment transport along the canyon axis showed clear differences during the period of the study, with some important events leading to strong intensifications of the current coupled with large transport of particle fluxes to the deepest parts of the canyon. Such events are primarily related to increases in river discharge and the occurrence of strong storms and cascading events during the winter. In summary, in this study it is shown that the dynamics of thewater masses and the currents in the study area convert the sharp western flank of the Blanes Canyon in a more active region that favors erosion processes than the eastern flank, which has a smoother topography and where the absence of erosional conditions yields to steadier sedimentary processes.Peer ReviewedPostprint (published version

Particle fluxes dynamics in Blanes submarine canyon (Northwestern Mediterranean)

Within the framework of the multidisciplinary RECS project and with the aim of describing the particle flux transfer from the continental shelf to the deep basin, an array of five mooring lines equipped with a total of five pairs of PPS3/3 sequential-sampling sediment traps and RCM-7/8 current meters were deployed 30 m above the bottom from March 2003 to March 2004 inside and outside the Blanes Canyon. One mooring line was located in the upper canyon at 600 m depth, one in the canyon axis at 1700 m depth and other two close to the canyon walls at 900 m depth. A fifth mooring line was deployed in the continental open slope at 1500 m water depth. The highest near-bottomdownwardparticle flux (14.50 g m-2 d-1)wasrecorded at the trap located in the upper canyon (M1), where continental inputs associated with the presence of the Tordera River are most relevant. On the other hand, the downward fluxes (4.35 g m-2 d-1) in the canyon axis (M2) were of the same order as those found in the western flank (M3) of the canyon. Both values were clearly higher than the value (1.95 g m-2 d-1) recorded at the eastern canyon wall (M4). The open slope (M5) mass flux (5.42 mg m-2 d-1) recorded by the sediment trap located outside the canyon system was three orders of magnitude lower than the other values registered by the inner canyon stations. The relevance of our data is that it explains how the transport pathway in the canyon occurs through its western flank, where a more active and persistent current toward the open ocean was recorded over the entire year of the experiment. Off-shelf sediment transport along the canyon axis showed clear differences during the period of the study, with some important events leading to strong intensifications of the current coupled with large transport of particle fluxes to the deepest parts of the canyon. Such events are primarily related to increases in river discharge and the occurrence of strong storms and cascading events during the winter. In summary, in this study it is shown that the dynamics of thewater masses and the currents in the study area convert the sharp western flank of the Blanes Canyon in a more active region that favors erosion processes than the eastern flank, which has a smoother topography and where the absence of erosional conditions yields to steadier sedimentary processes.Peer Reviewe