Articles scientifiques
M. Tomczak Jr (1977)
Continuous measurement of near-surface temperature and salinity in the NW African upwelling region between Canary Islands and Cap Vert during the winter of 1971-1972
Deep Sea Research, 24(12):1103-1119.
Continuous weekly records of sea surface temperature and salinity for January through March of 1972 on a fixed course between the Canary Islands and Cap Vert are used to investigate the distribution and inner structure of the water masses of this upwelling region. The large scale distributions of temperature and salinity (scales 200 km) are in agreement with the long-term climatological mean and show rapid response to wind variations. At scales 200 km the spectra of temperature and salinity fall off towards high wavenumbers with a slope slightly larger than 2, in agreement with earlier observations. Investigation of the original record shows a front off Cap Blanc separating two different water masses at the surface; it seems to be a permanent feature of the region. The water masses are North and South Atlantic Central Water (NACW and SACW), which have been brought to the surface by upwelling and termed North and South Atlantic Upwelled Water (NAUW and SAUW). In the area of NAUW there are variations of temperature and salinity at scales of 20 to 40 km that may arise from an undulating surface front, patches of newly upwelled water, or medium scale eddies. These variations disappear in the T-S diagram. The T-S diagram of SAUW falls into two or three distinct lines, which may only reflect the layering of water masses along the inclined separation level between NACW and SACW at intermediate depths. Other phenomena reflected in the record are areas of low salinity of some 20 to 50 km diameter off Nouakchott and indications for medium scale perturbations being formed from small scale variations.
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