Warmer Antarctic summers in the last two decades linked to earlier stratospheric final warming occurrences

We proposed a link between the interannual and decadal variability in Antarctic surface climate during the austral summertime (December-January) and the timing of stratospheric final warming (SFW) occurrences. This connection is based on 44 years of reanalysis data and in-situ observation spanning from 1979 to 2023. Positive surface pressure anomalies over Antarctica, associated with an earlier occurrence of SFW, develop through stratosphere-troposphere downward coupling, which leads to a warmer surface in Antarctica, except for  the Antarctic Peninsula where a cooler surface is observed. On the contrary, the surface pressure and temperature anomalies associated with the later occurrence of SFW exhibit almost opposite or weaker behaviors. Congruence analyses support that a trend towards earlier SFW occurrences can explain the pause of the cooling trend or a slight reversal into the warming trend of the interior Antarctic surface through strengthening anti-cyclonic surface circulation since the 2000s. The resulting surface temperature responses can leave imprints on sea-ice concentration trends in the high-latitude Southern Hemisphere, displaying the dipole anomalies with an increase and a decrease of sea ice over the Antarctic Peninsula and northern Ross Sea, respectively.