Atypical Western Mediterranean deep water formation during winter 2005

Abstract

The meteorological conditions in winter 2005, with anomalously low precipitation and unusual persistency of northerlies over the NW Mediterranean, caused a large extension both in time and space of deep convection processes. As a consequence, where convection typically gives rise to the Western Intermediate Waters (WIW) a New Western Mediterranean Deep Water (N-WMDW) was produced, slightly denser (+0.01kg m−3), warmer (+0.05ºC) and saltier (+0.03) than the usual WMDW. Moreover, near the continental slope, a cascading of colder and even denser water was found (-0.1ºC and +0.025 kg m−3), formed over the shelf (C-WMDW). In both cases it appears the high surface salinity as a responsible for the excess of density. The origin of this higher surface salinity is discussed