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A month of microstructure measurements in the Southern California Bight allowed to confirm the hypothesis that in ocean pycnocline, below the surface mixed layer, the probability distribution of turbulent kinetic energy dissipation rate ε averaged over equal time segments (2 s with 512‐Hz sampling rate, corresponding to about 1.4‐m vertical averaging) follows the Burr distribution suggested by Lozovatsky, Fernando, et al. (2017, https://doi.org/10.1002/2017JC013076). The bin‐median estimates of ε was well correlated with the medians of the Burr model. The parameters of the Burr distribution varied in time, but no relationship was found between these variations and the changes in wind patterns and phases of barotropic tide. In the range 10−9~ < ε < 10−8 W/kg, the dissipation rate could be related to internal wave activity in the region.

Measurements conducted in the southern Bay of Bengal (BoB) as a part of the ASIRI‐EBoB Program portray the characteristics of high‐frequency internal waves in the upper pycnocline as well as the velocity structure with episodic events of shear instability. A 20 h time series of CTD, ADCP, and acoustic backscatter profiles down to 150 m as well as temporal CTD measurements in the pycnocline at z = 54 m were taken to the east of Sri Lanka. Internal waves of periods ∼10–40 min were recorded at all depths below a shallow (∼20–30 m) surface mixed layer in the background of an 8 m amplitude internal tide. The absolute values of vertical displacements associated with high‐frequency waves followed the Nakagami distribution with a median value of 2.1 m and a 95% quintile 6.5 m. The internal wave amplitudes are normally distributed. The tails of the distribution deviate from normality due to episodic high‐amplitude displacements. The sporadic appearance of internal waves with amplitudes exceeding ∼5 m usually coincided with patches of low Richardson numbers, pointing to local shear instability as a possible mechanism of internal‐wave‐induced turbulence. The probability of shear instability in the summer BoB pycnocline based on an exponential distribution of the inverse Richardson number, however, appears to be relatively low, not exceeding 4% for Ri < 0.25 and about 10% for Ri < 0.36 (K‐H billows). The probability of the generation of asymmetric breaking internal waves and Holmboe instabilities is above ∼25%.

The deepwater formation in the northern part of the South Adriatic Pit (Mediterranean Sea) is investigated using a unique oceanographic data set. In situ data collected by a glider along the Bari-Dubrovnik transect captured the mixing and the spreading/re-stratification phase of the water column in winter 2018. After a period of about two weeks from the beginning of the mixing phase, a homogeneous convective area of ∼ 300 m depth breaks up due to the baroclinic instability process in cyclonic cones made of geostrophically adjusted fluid. The base of these cones is located at the bottom of the mixed layer and they extend up to the theoretical critical depth Zc. These cones, with a diameter of the order of internal Rossby radius of deformation (∼ 6 km) populate the ∼ 110-km wide convective site, develop beneath it and have a short life time of weeks. Later on, the cones extend deeper and intrusion from deep layers makes their inner core denser and colder. These observed features differ from the long-lived cyclonic eddies sampled in other ocean sites and formed at the periphery of the convective area in a post-convection period. So far, to the best of our knowledge, only theoretical studies, laboratory experiments and model simulations have been able to predict and describe our observations and no other in-situ information has yet been provided.

&lt;p&gt;The deepwater formation in the northern part of the South Adriatic Pit (Mediterranean Sea) during winter 2018 is investigated using in-situ glider data. After a period of about 2 weeks from the beginning of the mixing phase, a homogeneous convective area &amp;#8764;110-km-wide and &amp;#8764;300-m deep, breaks up due to the baroclinic instability process in cyclonic cones made of geostrophically adjusted fluid. The base of these cones is located at the bottom of the mixed layer, and they extend up to the theoretical critical depth&amp;#160;&lt;em&gt;Z&lt;/em&gt;&lt;em&gt;&lt;sub&gt;c&lt;/sub&gt;&lt;/em&gt;. These cones, with a diameter on the order of internal Rossby radius of deformation (&amp;#8764;6 km), populate the convective site, develop beneath it, and have a short lifetime of weeks. Later on, they extend deeper and intrusion from deep layers makes their inner core denser and colder. The breaking mechanism of these cyclonic spinning features occurring during the spreading phase and some bio-geochemical aspects associated to their evolution are also addressed. The observed cones differ from the long-lived cyclonic eddies sampled in other ocean sites and formed at the periphery of the convective area in a postconvection period. In-situ data are also corroborated by theoretical studies, laboratory experiments and model simulations.&lt;/p&gt;