Publication Date:
2020-12-09
Description:
An accurate numerical prediction of the oceanic upper layer velocity is a demanding requirement for
many applications at sea and is a function of several near-surface processes that need to be incorporated
in a numerical model. Among them, we assess the effects of vertical resolution, different vertical mixing
parameterization (the so-called Generic Length Scale –GLS– set of k–e, k–x, gen, and the Mellor–Yamada),
and surface roughness values on turbulent kinetic energy (k) injection from breaking waves.
First, we modified the GLS turbulence closure formulation in the Regional Ocean Modeling System
(ROMS) to incorporate the surface flux of turbulent kinetic energy due to wave breaking. Then, we
applied the model to idealized test cases, exploring the sensitivity to the above mentioned factors. Last,
the model was applied to a realistic situation in the Adriatic Sea driven by numerical meteorological forcings
and river discharges. In this case, numerical drifters were released during an intense episode of Bora
winds that occurred in mid-February 2003, and their trajectories compared to the displacement of satellite-
tracked drifters deployed during the ADRIA02-03 sea-truth campaign.
Results indicted that the inclusion of the wave breaking process helps improve the accuracy of the
numerical simulations, subject to an increase in the typical value of the surface roughness z0. Specifically,
the best performance was obtained using aCH = 56,000 in the Charnok formula, the wave breaking parameterization
activated, k–e as the turbulence closure model. With these options, the relative error with
respect to the average distance of the drifter was about 25% (5.5 km/day). The most sensitive factors in
the model were found to be the value of aCH enhanced with respect to a standard value, followed by
the adoption of wave breaking parameterization and the particular turbulence closure model selected.
Description:
Published
Description:
225-239
Description:
3.7. Dinamica del clima e dell'oceano
Description:
JCR Journal
Description:
restricted
Keywords:
wave breaking
;
turbulence
;
drifter
;
03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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