ANALYSIS
Mean transport and variability
The basic statistics of the Agulhas Undercurrent, i.e., means, variances, covariances, integral time scales, principal variance ellipses, time-mean transports, and spectra of velocity variance, will be calculated from the moored current and temperature time series.
Empirical Orthogonal Function (EOF) analysis will be employed to look at principal modes of variablility and as a filter to extract the coherent part of the velocity signal across the array.
Initially, we plan to compute EOFs on the full time series (mean included) and to use the sum of the first few EOFs (accounting for most of the variance) to deduce the coherent spatial structure of the Undercurrent. We can use the EOF-filtered time series for calculating spatial derivatives. At 1400m and 1800m we can form time series of vx, the prinicipal component of the relative vorticity. For each mooring, we can form time series of vz, the vertical shear of the horizontal along-stream current. To the extent that the AUC is in geostrophic balance, vz is also a time series of horizontal pressure gradient in the cross-stream direction.
- Introduction
- Velocity Structure
- Variability
- Water Masses and Potential Vorticity Structure
- Geostrophy and Transport
- Mooring Array
- Cross-stream sections
- Along-stream sections
- Synopticity and variability
- LADCP experiment design
- Interocean exchange Indian Ocean ventilation
- Velocity and PV fields
- Mean Transport and variability
- Characterisation of mixing