Relationships between Antarctic sea-ice concentration, wind stress and temperature temporal variability, and their changes with distance from the coast

Abstract

Daily Antarctic sea-ice concentration, wind and temperature data for the years 1988-94 were analyzed using Fourier techniques to determine their temporal spectra for three equal-length 'seasons'. The percentage of the total variance explained (VE) by each individual wave (i.e. frequency) was calculated, and spatial averages made over six latitudinal bands surrounding Antarctica. Comparisons of the sea-ice concentration, wind stress and surface air-temperature spectra showed sea-ice concentration VE has smallest, and wind-stress VE greatest, value in the synoptic time-scales. Conversely, in the 20-25 day window the wind-stress VE is smallest, and sea-ice concentration VE greatest. This 'red shift' of the sea-ice concentration suggests it has inertia to the wind stress and temperature forcing. Results show the magnitude of the red shift varies with not only time of year, but also distance from the coast, and is dependent upon the position of the Antarctic circumpolar trough.