Changing hydrographic structures across the Lazarev Sea
Deep water originating in the North Atlantic is transported across theAntarctic Circumpolar Current by eddies and enters the Weddell Gyresouth of Africa. As it does so it rises up from mid depth towards thesurface. The separate temperature and salinity maxima, the Upperand Lower Deep Waters, converge to form the Warm Deep Water.cores of this water mass on the southern flank of the Weddell Gyreshow a change in characteristic as they flow westward in the LazarevSea. Observations have been made along four meridional sections at3°E, 0°, 3°W and 6°W between 60 and 70°S during the PolarsternLAKRIS Cruise ANTXXIII/2 in December 2005. These show that aheterogeneous series of warm and salty cores entering the regionfrom the east both north and south of Maud Rise (65°S, 3°W)gradually merge and become more homogeneous towards the west.Comparison of the data with that from earlier years shows just howvariable the water mass characteristics can be. The gradual tighteningof the TS-relationship is indicative of mixing processes and allowsdiagnosis of which mixing processes are important and estimates ofthe mixing rates.