Abstract
Changes to the Southern Hemisphere (SH) surface westerlies not only
affect air temperature, storm tracks and precipitation; they are also
pivotal in controlling global ocean circulation, ocean heat transport,
and ocean carbon uptake. Wind-forced ocean perturbation experiments have
commonly applied idealized poleward wind shifts ranging between 0.5 and
10 degrees of latitude, and wind intensification factors of between 10
and 300%. In addition, changes in winds are often prescribed ad-hoc
without consistently accounting for physical constraints and can neglect
important regional and seasonal differences. Here we quantify historical
and future projected SH westerly wind changes based on examination of
CMIP5, CMIP6 and reanalysis data. Under a high emission scenario, we
find a projected end of 21st Century annual mean
westerly wind increase of ~10% and a poleward shift of
~0.8° latitude, although there are also significant
seasonal and regional variations.