Temporal variability in the Antarctic Polar Front (2002-2014)

We investigate intraannual to interannual variability in the Antarctic Polar Front (PF) using weekly PF realizations spanning 2002-2014 (found at doi.pangaea.de/10.1594/PANGAEA.855640). While several PF studies have used gradient maxima in sea surface temperature (SST) or height to define its location, results from this study are based on a PF defined using SST measurements that avoid cloud contamination and the influence of steric sea level change. With a few regional exceptions, we find that the latitudinal position of the PF does not vary seasonally, yet its temperature exhibits a clear seasonal cycle. Consistent with previous studies, the position and intensity of the PF is largely influenced by bathymetry; generally, over steep topography, we find that the front intensifies and interannual variability in its position is low. We also investigate drivers of PF variability in the context of large-scale climate variability on various spatial and temporal scales, but find that the major modes of Southern Hemisphere climate variability explain only a tiny fraction of the interannual PF variance. Over the study time period, the PF intensifies at nearly all longitudes while exhibiting no discernible meridional displacement in its zonal mean path.