Abstract. In this work, a multi-parameter inter-comparison of diverse ocean forecast models was conducted at the sea surface ranging from global to local scales in a two-phase stepwise strategy. Firstly, a comparison of CMEMS GLOBAL and the nested CMEMS IBI regional system was performed against satellite-derived and in situ observations. Results highlighted the overall benefits of both the GLOBAL direct data assimilation in open water and the increased horizontal resolution of IBI in coastal areas. Besides, IBI (Iberia–Biscay–Ireland) proved to capture shelf dynamics by better representing the horizontal extent and strength of a river freshwater plume, according to the results derived from the validation against in situ observations from a buoy moored in NW Spain. Secondly, a multi-model inter-comparison exercise for 2017 was performed in the Strait of Gibraltar among GLOBAL, IBI, and SAMPA (Sánchez-Garrido et al., 2013) high-resolution coastal forecast systems (partially nested to IBI) in order to elucidate the accuracy of each system to characterize the Atlantic Jet (AJ) inflow dynamics. A quantitative validation against hourly currents from high-frequency radar (HFR) highlighted both the steady improvement in AJ representation in terms of speed and direction when zooming from global to coastal scales through a multi-nesting model approach and also the relevance of a variety of factors at local scale such as a refined horizontal resolution, a tailored bathymetry, and a higher spatio-temporal resolution of the atmospheric forcing. The ability of each model to reproduce a 2 d quasi-permanent full reversal of the AJ surface inflow was examined in terms of wind-induced circulation patterns. SAMPA appeared to better reproduce the reversal events detected with HFR estimations, demonstrating the added value of imposing accurate meteorologically driven barotropic velocities in the open boundaries (imported from the NIVMAR (Álvarez-Fanjul et al., 2001) storm surge model) to take into account the remote effect of the atmospheric forcing over the entire Mediterranean basin, which was only partially included in IBI and GLOBAL systems. Finally, SAMPA coastal model outputs were also qualitatively analysed in the western Alboran Sea to put in a broader perspective the context of the onset, development, and end of such flow reversal episodes.
Abstract. The Mediterranean Outflow Water (MOW) is a dense water mass originated in the Strait of Gibraltar. Downstream of the Gulf of Cádiz, the MOW forms a reservoir region west of the Iberian continental slopes at a buoyant depth of approximately 1000 m. This region plays a key role as the main centre where the MOW is mixed and distributed into the North Atlantic. The seafloor in this area is characterized by the presence of a complex bathymetry with three abyssal plains separated by mountain chains. Although the topographic features do not reach the surface, they influence ocean flows at intermediate and deep ocean layers, conditioning the distribution and circulation of MOW. The Copernicus Marine Environmental Monitoring Service (CMEMS) Iberian–Biscay–Ireland (IBI) ocean reanalysis is used to provide a detailed view of the circulation and mixing processes of MOW near the Iberian and African continental slopes. This work emphasizes the relevance of the complex bathymetric features defining the circulation processes of MOW in this region. The high resolution of the IBI reanalysis allows us to make a description of the mesoscale features forced by the topography. The temperature, salinity, velocity, transport, and vorticity fields are analysed to understand the circulation patterns of MOW. The high-resolution circulation patterns reveal that Horseshoe Basin and the continental slope near Cape Ghir (a.k.a. Cap Rhir or Cabo de Aguer) are key areas controlling the mixing processes of MOW with the surrounding water masses, mainly North Atlantic Central Water (NACW) and Antarctic Intermediate Water (AAIW). The water mass variability is also analysed by means of composite analysis. Results indicate the existence of a variability in the MOW tongue which retracts and expands westwards in opposition to the movement of the underlying North Atlantic Deep Water.
Abstract. The Mediterranean Outflow Water (MOW) is a dense water mass originated in the Gibraltar Straight. After exiting the Gulf of Cadiz, the MOW forms a reservoir region west of the Iberian continental slopes with a buoyant depth of approximately 1000 m depth. This region is a key role as the main centre where the MOW is mixed and distributed into the North Atlantic. The seafloor in this area is characterised by the presence of a complex bathymetry with three abyssal plains separated by mountain chains. Despite of this topographic features does not reach the surface, they influence ocean flows at intermediate and deep ocean layers conditioning the distribution and circulation of MOW. The CMEMS IBI ocean reanalysis is used to provide a detailed view of the circulation and mixing processes of MOW near the Iberian and African Continental slopes. This work emphasizes the relevance of the complex bathymetric features defining the circulation processes of MOW in this region. The high resolution of the IBI reanalysis allows to make a description of the meso-scale features forced by the topography. The temperature, salinity, velocity, transport, and vorticity fields are analysed to understand the circulation patterns of MOW. The high-resolution circulation patterns found reveals that Horseshoe Basin and the continental slope near Cape Ghir are key areas controlling the mixing processes of MOW with the surrounding waters mases, mainly North Atlantic Central Water (NACW), and Antarctic Intermediate Water (AAIW). The water masses variability is also analysed by means of composite analysis, results indicate the existence of a variability of the MOW tongue which retracts and expands westwards in opposition to the movement of the underlying North Atlantic Deep Water.
Abstract. The ocean has the largest heat capacity of any single component of the climate system and plays a key dominant role in global heat content changes. Several recent studies have found that the Ocean Heat Content (OHC) has increased during the last decades, not only at a global scale, but also at regional/basin scales. To analyse OHC variability in the Iberia-Biscay-Ireland (IBI) region, several Copernicus Marine model and observed derived products are used together to provide multi-product estimations of OHC anomalies over the water column (at layers upper 150 m, 700 m, and 2000 m). This work provides an exhaustive analysis of spatial and temporal variability of OHC in the Northeast Atlantic region providing an analysis of area-averaged time series, trend maps, and trends linked with the main water masses found in the IBI region. The analysis of trends reveals that, despite a significant warming of the region in the period 1993–2020 (at rates of 0.4 W/m2), the thermohaline variability of subsurface water masses mainly dominates the OHC variability over the upper 2000 m. Additionally, vertical profiles of OHC trends are investigated, linking them with the vertical distribution of water masses; and describing how coupled inter-annual variability of Sub-Artic Intermediate Water, Mediterranean Outflow Water, and Labrador Sea Water accounts for an important part of the total OHC variability in the region.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.