Publication Date:
2020-05-26
Description:
A multidisciplinary survey on board R.V. Poseidon off Angola and northern Namibia in April 1999 allowed a large-scale view of the South-East Atlantic boundary current system. The data set comprises meteorological, hydrographical, biological and chemical data. Sequences of satellite images of sea-surface temperature and wind stress provided additional synoptic information. Several mesoscale cyclonic gyres were observed embedded in a larger area of low dynamic height, known as the Angola Gyre. The most developed mesoscale feature was the subthermoclinal Angola Dome detected at 9 degreesS, 8.5 degreesE. At the beginning of April, the Angola-Benguela Frontal Zone (ABFZ) was found at an unusually southerly position near 19 degreesS. During the time of the cruise, the zone moved rapidly northward. The dynamics of this event are discussed in detail. The high-frequency temporal variations of the front were closely related to local wind forcing. Below the thermocline the conditions were more persistent. The ABFZ was represented as a front between different types of Central Water. The existence of a poleward undercurrent below the ABFZ, reported in recent publications, was not verified from direct current measurements. However, water mass distribution suggests overall poleward transport below the thermocline.
Type:
Article
,
PeerReviewed
Format:
text
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