Data from: New perspectives on frontal variability in the southern ocean

The frontal structure of the Southern Ocean is investigated using the
Wavelet/Higher Order Statistics Enhancement (WHOSE) frontal detection
method, introduced in Chapman (2014). This methodology is applied to 21
years of daily gridded absolute dynamic topography (ADT) data to obtain
daily maps of the locations of the fronts. By forming frontal occurrence
frequency maps and then approximating these occurrence-maps by a
superposition of simple functions, the time-mean locations of the fronts,
as well as a measure of their capacity to meander, are obtained and
related to the frontal locations found by previous studies. The spatial
and temporal variability of the frontal structure is then considered. The
number of fronts is found to be highly variable throughout the Southern
Ocean, increasing (‘splitting’) downstream of large bathymetric features
and decreasing (‘merging’) in regions where the fronts are tightly
controlled by the underlying topography. These splitting/merging events
are related to changes in the underlying frontal structure whereby regions
of high frontal occurrence cross or spread over streamfunction contours.
In contrast to the number of fronts, frontal meandering remains relatively
constant throughout the Southern Ocean. Little to no migration of the
fronts over the 1993-2014 time period is found, and there is only weak
sensitivity of frontal positions to atmospheric forcing related to the
Southern Annular Mode or the El Niño Southern Oscillation. Finally, the
implications of these results for the study of cross-stream tracer
transport is discussed.