Warm Temperature Anomalies Associated with Snowfall in Antarctica

Antarctica, the coldest and driest continent, is home to the largest ice sheet. A common feature of polar regions is the warming associated with snowfall, as moist oceanic air and cloud cover contribute to increase the surface temperature. Consequently, the ice accumulated onto the ice sheet is deposited under unusually warm conditions. Here we use the polar-oriented atmospheric model MAR to study the statistical difference between average and snowfall-weighted temperatures. Most of Antarctica experiences a warming scaling with snowfall, although with strongest warming at sites with usually low accumulation. Heavier snowfalls in winter contribute to cool the snowfall-weighted temperature, but this effect is overwritten by the warming associated with atmospheric perturbations responsible for snowfall, which particularly contrast with the extremely cold conditions in winter. Disturbance in apparent annual temperature cycle and interannual variability may have major implications for water isotopes, which are deposited with snowfall and commonly used for paleo-temperature reconstructions.