ISSN 2070-7401 (Print), ISSN 2411-0280 (Online)
Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa


Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2020, Vol. 17, No. 4, pp. 231-237

Dynamics of the seasonal thermocline upper boundary depth in dependence on the Rim Current velocity (from satellite altimetry and drifter experiment data)

A.A. Sizov 1 , T.M. Bayankina 1 , N.E. Lebedev 1 
1 Marine Hydrophysical Institute RAS, Sevastopol, Russia
Accepted: 02.06.2020
DOI: 10.21046/2070-7401-2020-17-4-231-237
Reaction of the seasonal thermocline upper boundary to the changing velocity of the Rim Current is under consideration. The analysis was carried out using the sea upper layer temperature data from the distributed temperature sensor systems of drifting buoys (drifters) and data on the Rim Current geostrophic velocity. An estimation of the latter was made by means of satellite altimetry in January – March when convection and turbulent mixing formed the main features of the seasonal thermocline. The performed analysis revealed that the upper boundary of the seasonal thermocline (which is also the lower boundary of the upper quasi-isothermal layer) deepens as the Rim Current velocity increases, and with its weakening, this boundary rises to shallower depths. This process is observed in the Rim Current zone both in the western and eastern parts of the Black Sea. An explanation of the mechanism of the Rim Current velocity influence on the change in the depth of the seasonal thermocline upper boundary is proposed. For this, we use the known data that the region of maximal Rim Current velocities (the jet of current) is located above the seasonal thermocline, while in the jet boundary layer there appear wave oscillations which propagate into the thermocline, causing changes in its characteristics. Qualitatively, the relevance of this assumption is confirmed by experimental data.
Keywords: upper quasi-isothermal layer, geostrophic velocity, seasonal thermocline, Rim Current
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