Assessing shelf mixing using CTD, ADCP, and free falling shear probe turbulence data

• The use of potential overturns structure for estimating dissipation rates.
• Dissipation rates derived by integration of turbo microprofilers' shear spectrum.
• CTD, ADCP, MSP data for assessing vertical turbulent diffusion in North Aegean Sea.
• Comparison of the overturn and the shear integration methods presumes isotropy.
• Partial agreement between cospatial and synchronous CTD and MSP overturn data.

CTD, ADCP and free-falling microstructure profiler data from Thermaikos Gulf of Northern Aegean Sea in Greece are analyzed in order to (a) gain an insight in the vertical diffusion processes of the area and (b) compare the methods of vertical diffusivity assessment based on microstructure profiler shear data and on potential density overturns. The analysis reveals the presence of mixing events at the top mixed layer as well as above the upper thermocline boundary. It is consistent with a notable change in the susceptibility of the water column to turbulent events, within a month's period as well as convective instability possibly related to riverine discharge. The comparison of the profiles of vertical shear of horizontal velocity and of density presumes isotropy of the turbulent field.