Inertial Currents in Western Continental Black Sea Shelf

Abstract

The western Black Sea shelf has the largest width of the continental platform of entire Black Sea basin, except for the north-western corner. The Black Sea dynamics is driven by two synergic mechanisms: the considerable river input in the north-western corner, deflected southward by the Coriolis force and the surface wind stress that has an average anticlockwise curl. Their combined action controls the global mass transport in the upper (active) layer. In this paper, in-situ measurements of the currents data and diagnostic calculations for the inertial currents are analysed and discussed. The purpose of the present work is to furnish relevant arguments using the Progressive Vector Diagram as well as the Discrete Fourier Transform on the sea currents data and to report the results on inertial motion in the western Black Sea shelf. The selected time series were recorded in the middle of the Romanian shelf, at 44°10′N, 29°22′E (52 m of water depth), with the one or two instruments suspended from a ship anchored for several days, only one series at the southern end of the Mamaia bight at 44°12′N–28°20′E (12 m water depth). The depth-averaged current amplitudes varied by time from 7.6 to 21.3 cm/s. Calculated inertial currents periods in the north-western Black Sea range between 16.5 and 17.5 h.