Following publications have been announced by our department Hydrodynamics and Data Assimilation. For further information please contact Dr. Joanna Staneva, co-author of the publications:
Benetazzo, A., Barbariol, F., Staneva, J., Davison, S., Ricchi, A., Behrens, A., Gayer, G., & Pezzutto, P. (2021): Climatology and 2019 anomaly of maximum waves in the Mediterranean and Black Seas. Section 2.8, In: Schuckmann, K., et al. (eds): Copernicus Marine Service Ocean State Report, Issue 5, Journal of Operational Oceanography, 14:sup1, 1-185, doi:10.1080/1755876X.2021.1946240
Statement of main outcome:
There is general consensus that high-quality predictions of extreme events during marine storms can substantially contribute to avoiding or minimising human and material damage, especially in busy waterways such as the Mediterranean and Black Seas. Reliable wave forecasts and hindcasts, together with long-term statistical analysis of extreme conditions, are then of utmost importance for monitoring marine areas. So far, however, the wave climate characterisation (average and anomaly relative to the average) has focused on the bulk characterisation of the significant wave height Hs, and it has lacked a description of the individual waves, such as the maximum ones that may occur at a given location in the sea. To fill this gap, in this section, we provide the intensity and geographical distribution of the maximum waves in the Mediterranean and Black Seas over 27 years (1993–2019), by representing the average annual (1993–2018) and anomaly for 2019 relative to the average of the 99th percentile of the expected maximum wave height Hm and crest height Cm. The analysis combines wave model hindcasts available through CMEMS model setup and the wave model WAVEWATCH III®, both forced with ECMWF ERA5 reanalysis winds. Results show that in 2019 maximum waves were smaller than usual in the Black Sea (anomalies of Hm up to −1.5 m), while in the Mediterranean Sea a markedly positive anomaly (+2.5 m for Hm) was found in the southern part of the basin. The peculiar 2019 configuration seems to be caused by a widespread atmospheric stability over the Black Sea and by depressions that rapidly passed over the Mediterranean Sea.
Bonaduce, A., Cipollone, A., Johannessen, J.A., Staneva, J., Raj, R.P., & Aydogdu, A. (2021): Ocean Mesoscale Variability: A Case Study on the Mediterranean Sea From a Re-Analysis Perspective. Front. Earth Sci. 9:724879, doi:10.3389/feart.2021.724879
Abstract:
The mesoscale variability in the Mediterranean Sea is investigated through eddy detection techniques. The analysis is performed over 24 years (1993–2016) considering the three-dimensional (3D) fields from an ocean re-analysis of the Mediterranean Sea (MED-REA). The objective is to achieve a fit-for-purpose assessment of the 3D mesoscale eddy field. In particular, we focus on the contribution of eddy-driven anomalies to ocean dynamics and thermodynamics. The accuracy of the method used to disclose the 3D eddy contributions is assessed against pointwise in-situ measurements and observation-based data sets. Eddy lifetimes ≥ 2 weeks are representative of the 3D mesoscale field in the basin, showing a high probability (> 60%) of occurrence in the areas of the main quasi-stationary mesoscale features. The results show a dependence of the eddy size and thickness on polarity and lifetime: anticyclonic eddies (ACE) are significantly deeper than cyclonic eddies (CE), and their size tends to increase in long-lived structures which also show a seasonal variability. Mesoscale eddies result to be a significant contribution to the ocean dynamics in the Mediterranean Sea, as they account for a large portion of the sea-surface height variability at temporal scales longer than 1 month and for the kinetic energy (50–60%) both at the surface and at depth. Looking at the contributions to ocean thermodynamics, the results exhibit the existence of typical warm (cold) cores associated with ACEs (CEs) with exceptions in the Levantine basin (e.g., Shikmona gyre) where a structure close to a mode-water ACE eddy persists with a positive salinity anomaly. In this area, eddy-induced temperature anomalies can be affected by a strong summer stratification in the surface water, displaying an opposite sign of the anomaly whether looking at the surface or at depth. The results show also that temperature anomalies driven by long-lived eddies (≥ 4 weeks) can affect up to 15–25% of the monthly variability of the upper ocean heat content in the Mediterranean basin.