We use Lagrangian diagnostics (the leaking and the exchange methods) to characterize surface transport out of and between selected regions in the Western Mediterranean. Velocity fields are obtained from a numerical model. Residence times of water of Atlantic origin in the Algerian basin, with a strong seasonal dependence, are calculated. Exchange rates between these waters and the ones occupying the northern basin are also evaluated. At surface, northward transport is dominant, and involves filamental features and eddy structures that can be identified with the Algerian eddies. The impact on these results of the presence of small scale turbulent motions is evaluated by adding Lagrangian diffusion.
Understanding how climate change will affect oceanic fluid transport is crucial for environmental applications and human activities. However, a synoptic characterization of the influence of climate change on mesoscale stirring and transport in the surface ocean is missing. To bridge this gap, we exploit a high-resolution, fully-coupled climate model of the Mediterranean basin using a Network Theory approach. We project significant increases of horizontal stirring and kinetic energies in the next century, likely due to increments of available potential energy. The future evolution of basin-scal…
MedFormer: a data-driven model for forecasting the Mediterranean Sea
CMCC Foundation - Euro-Mediterranean Center on Climate Change（CMCC基金会——地中海气候中心）；University of Salento（萨勒诺大学）；Columbia University（哥伦比亚大学）；Learning the Earth With Artificial Intelligence and Physics (LEAP) NSF STC（利用人工智能和物理学习地球（LEAP）NSF STC）
In the stably stratified ocean, small-scale turbulence is important for vertical exchange and hence for the mixing of water masses and suspended matter. To observationally study turbulent motions and the buoyancy- and shear-generators behind them, a 100-m tall array of high-resolution temperature (T) sensors was moored at a 2480-m deep seafloor near the steep continental slope of the Western Mediterranean Sea. The area is dominated by boundary flow, (sub-)mesoscale eddies, internal waves, wintertime dense water formation, and very weak vertical density stratification. Various physical oceanogr…
Vertical transport in the ocean plays a critical role in the exchange of freshwater, heat, nutrients, and other biogeochemical tracers. While there are situations where vertical fluxes are important, studying the vertical transport and displacement of material requires analysis over a finite interval of time. One such example is the subduction of fluid from the mixed layer into the pycnocline, which is known to occur near density fronts. Divergence has been used to estimate vertical velocities indicating that surface measurements, where observational data is most widely available, can be used …
We study the vertical dispersion and distribution of negatively buoyant rigid microplastics within a realistic circulation model of the Mediterranean sea. We first propose an equation describing their idealized dynamics. In that framework, we evaluate the importance of some relevant physical effects: inertia, Coriolis force, small-scale turbulence and variable seawater density, and bound the relative error of simplifying the dynamics to a constant sinking velocity added to a large-scale velocity field. We then calculate the amount and vertical distribution of microplastic particles on the wate…
Here we propose a technique that successfully reconstructs ocean bathymetry from the free surface velocity and elevation data. This technique is based on the principles of open-channel hydraulics, according to which a sub-critical flow over a seamount creates a free surface dip. The proposed method recognizes that such free surface dip contains the signature of the bottom topography, hence inverts the free surface to reconstruct the topography accurately. We applied our inversion technique on re-analysis data, and reconstructed the Mediterranean and the Red sea bathymetries of $1/12\degree$ re…
Turbulent and internal wave motions are important for the exchange of momentum, heat and suspended matter in the deep-sea which is generally stably stratified in density. Turbulence-generation models involve shear of vertical current differences that deforms the stratified waters, and convection that is drive by (unstable) buoyancy. Shear-generation is found more general in the well-stratified ocean-interior, while convection is known to occur near the sea-surface, e.g. via nighttime cooling. Far below the surface, the Western-Mediterranean Sea is very weakly stratified and offers opportunity …
Decadal wave reconstruction in the Mediterranean Sea with graph neural networks
CMCC Foundation – Euro-Mediterranean Center on Climate Change（CMCC基金会-地中海气候变化中心）；Department of Physics and Astronomy, University of Bologna（博洛尼亚大学物理与天文系）；Department of Computer Science, University of Helsinki（赫尔辛基大学计算机系）
Linking Horizontal and Vertical Submesoscale Lagrangian Dynamics South of the Ibiza Channel
Institute for Cross Disciplinary and Complex Systems (IFISC), CSIC-UIB（交叉学科与复杂系统研究所 (IFISC)，CSIC-UIB）；Mediterranean Institute for Advanced Studies (IMEDEA), CSIC-UIB（地中海高级研究所 (IMEDEA)，CSIC-UIB）；Instituto de Ciencias Marinas de Andalucia (ICMAN-CSIC)（安达卢西亚海洋科学研究所 (ICMAN-CSIC)）
The redistribution of matter in the deep-sea depends on water-flow currents and turbulent exchange, for which breaking internal waves are an important source. As internal waves and turbulence are essentially three-dimensional 3D, their dynamical development should ideally be studied in a volume of seawater. However, this is seldom done in the ocean where 1D-observations along a single vertical line are already difficult. We present the design, construction and successful deployment of a half-cubic-hectometer (480,000 m3) 3D-T mooring array holding 2925 high-resolution temperature sensors to st…
