Figure 17 a,b,c,d.

a) (top left) Acoustic travel time at 987 decibar (tau(987), plotted on the x-axis) is mapped to acoustic travel time at 1500 decibar (tau(1500), on the y-axis) for use with GEM-ETTA parameterizations at SN 62, which was deployed at 987 dbar on the continental slope. Travel times were computed from the Cape Basin hydrographic database (N = 561).

b) (top right) Tau(1942) decibar is mapped to tau(1500) for use with GEM-ETTA parameterizations at SN 56, which was deployed near the base of the continental slope.

c) (bottom left) Tau (2621) is mapped to tau(1500) for use with GEM-ETTA parameterizations at SN 61, which was deployed on the Walvis Ridge.

d) (bottom right) Tau(3000) is mapped to tau(1500) for use with GEM-ETTA parameterizations at SN 58 and 59, both of which were deployed in the Cape Basin. Tau at levels below 3000 decibar correlates to tau(3000) with r^2 > 99.8% and deeper levels are therefore assumed to be invariant (offset by only a constant value) with respect to tau(3000). This mapping is thus used for BEST PIES moorings SN 58 and SN 62, both of which which were deployed at over 5000 m depth.