CR 48:73-84 (2011)  -  DOI: https://doi.org/10.3354/cr01032

ABSTRACT: The manifestation in the Baltic Sea of a seasonal, structural, thermally-induced front (a direct analogue of the lacustrine thermal bar) and its specific features after winters of different severity are examined. Analysis of long-term, spring-period, monthly mean SST data reveals that surface water temperatures first exceed the (salinity-dependent) temperature of maximum density (Tmd) in the southern part of the Baltic Sea. This phenomenon advances northwards at a speed of about 11 to 16 km d^–1, traversing the breadth of the sea within 8 to 10 wk. Surface temperature measurements across the Tmd-isotherm demonstrate that after the severe winter of 2002-2003 the frontal zone was highly pronounced, with a horizontal temperature gradient 10 to 100 times as large as the long-term monthly mean equivalent. Although the horizontal gradient was smaller after the mild winter of 2006-2007, it was still 10 times as large as the long-term monthly mean gradient. A clear correlation of thermal front advancement with biological parameters is revealed: an area of elevated chlorophyll a (about 200 km in width) associated with the Tmd was observed after severe winters, with the characteristic life-time of this zone 1 mo longer than that occurring after mild winters.

KEY WORDS: Temperature of maximum density · Thermal bar · Mixing · Baltic Sea

Full text in pdf format

Cite this article as: Demchenko N, Chubarenko I, Kaitala S (2011) The development of seasonal structural fronts in the Baltic Sea after winters of varying severity. Clim Res 48:73-84. https://doi.org/10.3354/cr01032 Export citation Share:    Facebook - - linkedIn