Variability of the currents’ vertical structure in the western Subtropical Atlantic and meridian heat transport

A.B. Polonsky✉, S.B. Krasheninnikova

Marine Hydrophysical Institute, Russian Academy of Sciences, Sevastopol, Russian Federation

✉ e-mail: apolonsky5@mail.ru

Abstract

Based on the WOCE (1988–1993) and RAPID (2004–2006) instrumental data, seasonal and synoptic variability of the currents’ vertical structure in the western part of the Northern Subtropical Anticyclonic Circulation (NSAC) is analyzed and its contribution to formation of the meridian heat transport is defined. Maximum of the seasonal cycle annual harmonic is observed in summer–autumn and its minimum – in winter – spring. The secondary maximums are revealed in late spring and mid autumn. Approximately 40 % of total variability of the currents’ field falls on the superposition of the annual and semi-annual harmonics. Synoptic fluctuations with the periods 3–30 and 51–135 days condition a substantial portion (up to 50–60 %) of hydrothermodynamic parameters’ variability in the upper and intermediate layers. A portion of variability with the period 31–50 days does not exceed 10 % of total dispersion. Influence of synoptic-scale vortex transports on the meridian thermohaline circulation and the associated meridian heat transport is most significant in the thermocline. With the seasonal variations taken into account, the synoptic vortices’ contribution to the integral heat transport in the western part of NSAC (in vicinity of 26 °N) estimated by the RAPID instrumental data does not exceed 5 %.

Keywords

seasonal and synoptic variability of currents, meridian heat transport, RAPID and WOCE instrumental data, Subtropical Atlantic

For citation

Polonsky, A.B. and Krasheninnikova, S.B., 2015. Variability of the currents’ vertical structure in the western Subtropical Atlantic and meridian heat transport. Physical Oceanography, (3), pp. 35-49. doi:10.22449/1573-160X-2015-3-35-49

DOI

10.22449/1573-160X-2015-3-35-49

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