Impact of Ozone depletion on Antarctic surface climate

We look at the surface impacts of ozone depletion in two 20-year simulations with the LMDZ atmospheric general circulation model, with prescribed ozone climatologies representative of the 1960s and 2000s decades. The only significant impacts are in the summer (DJF) seasons; the model reproduces the poleward shift of the tropospheric jet and the usual associated changes. Over Antarctica, there is a surface cooling and drying, most pronounced over East Antarctica. To distinguish direct impacts of ozone depletion from ones linked with the jet shift, we then reconstruct expected impacts from the simulated variability of the jet at intra-seasonal timescales. Over the Southern Ocean, all of the temperature and precipitation changes are well explained by the jet shift. The drying over Antarctica is however not present at the intra-seasonal timescale. The detailed surface energy budget also suggests that ozone depletion has direct radiative impacts in addition to the ones mediated by the jet shift, leading in particular to faster downslope surface winds.