Transport of upper ocean boundary current in sub-tropical South Atlantic
from Argo and Altimetry
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Benguela Current Brazil Current |
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Methods
Deriving fields of horizontal velocity
Details on the methodology can be found in Schmid (2014) and Majumder et al. (2016).
1. Generating synthetic dynamic height profiles
Temperature and salinity profiles from Argo floats are used to derive dynamic height profiles.
The relationship between sea surface height and in situ dynamic height is used to generate synthetic dynamic height profiles on a regular grid.
2. Computation of velocity
Geostrophic velocity is computed for each section from the synthetic dynamic height profiles. The reference velocity is derived from the climatological subsurface velocity derived from Argo and other float trajectories.
The wind stress from various wind products (NCEP/NCAR Reanalysis II, ERA interim) are used to compute the Ekman velocities and transport.
3. Estimation of the transport in the Brazil Current and Benguela Current
Transport time series for the eastern and western boundaries in the subtropical South Atlantic are derived from the three-dimensional velocity field.
The methods are described in schmid and Majumder (2017) for the Brazil Current and Majumder and schmid (2017) for the Benguela Current.
References
Schmid, C. (2014): Mean vertical and horizontal structure of the subtropical circulation in the South Atlantic from three-dimensional observed velocity fields. Deep Sea Research I, 91 (9), 50-71, doi: 10.1016/j.dsr.2014.04.015 [PDF]
Schmid, C. and S. Majumder (2017): An Observations and Model-based Analysis of the Temporal Variability of the Brazil Current. Ocean sciences, doi:10.5194/os-2017-59
Majumder, S. and Claudia Schmid (2017): A study of the variability in the Benguela Current volume transport. Ocean sciences, doi:10.5194/os-2017-63
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