Thermohaline structure of the water in the Southwestern Atlantic

 

Vertical and horizontal thermohaline structure of the waters in the Southwestern Atlantic on the basis of historical data are investigated. The distribution of the water masses according to the vertical water types: Tropical (TW) and Subtropical (STW) is shown. We present a new classification of the surface and subsurface water masses: tropical low-salinity water -TLSW ( T,S-index -18,5/34.4/0m ); tropical surface water-TSW (18.9/35.85/0-11m); tropical tropospheric water-TTW (18.9/ 36.11/75m); subtropical low-salinity water -STLSW (14.2/33.00/0m); subtropical surface water-STSW (13.6/35.17/0-15m); subtropical tropospheric water -STTW (13.4/ 35.29/63m). T-S characteristics of intermediate and deep waters are confirmed. We show the spatial stable conservation below the mixed layer (>50-100m) of the TS-relationships: [5/34.25], [7/34.4], [10/34.8], [12/35.1], [15/35.6] and [18/36.1]. We chose the frontal zones when the following rough changes of surface depths occur: a) TS-relationships; b) seasonal and main pycnoclines; c) minimum salinity of the antarctic intermediate water and d) the maximum salinity of the north atlantic deep water. We also classify the interfrontal zones: Subantarctic Zone -SAZ, Subtropical Zone - STZ and Brazil Current Zone-BCZ and fronts: SSTF- South Subtropical Front, NSTF-North Subtropical Front, PSTF-Principal Subtropical Front, and BCSTF - Brazil Current Subtropical Front.