The Extraordinary March 2022 East Antarctica 'Heat' Wave. Part I: Observations and Meteorological Drivers
This record-shattering event saw numerous monthly temperature records being broken including a new all-time temperature record of -9.4° C on March 18 at Concordia Station despite March typically being a transition month to the Antarctic coreless winter. The driver for these temperature extremes was an intense atmospheric river advecting subtropical/mid-latitude heat and moisture deep into the Antarctic interior. The scope of the temperature records spurred a large, diverse collaborative effort to study the heatwave’s meteorological drivers, impacts, and historical climate context which included 54 scientists from 14 countries.
Antarctic climate extremes are highly sensitive to perturbations in the mid-latitudes and sub-tropics. This heatwave redefined our expectations of the Antarctic climate. Despite the rare chance of occurrence based on past climate, a future temperature extreme event of similar magnitude is possible, especially given anthropogenic climate change. Publishing this study, which covered so many different aspects across different scientific disciplines, was only possible thanks to a massive international collaboration that facilitated rapid access to various datasets. This collaboration across nations continues, through ongoing research into Antarctic extreme weather and how it impacts sea level rise and demonstrates the value of peaceful international collaboration that is the rule in Antarctica.
In Part 1, we focus on describing those temperature records along with the intricate meteorological drivers that led to the most intense atmospheric river observed over East Antarctica. These efforts describe the Rossby wave activity forced by intense tropical convection over the Indian Ocean. This led to an atmospheric river and warm conveyor belt intensification near the coastline which reinforced atmospheric blocking deep into East Antarctica. The resulting moisture flux and upper-level warm air advection eroded the typical surface temperature inversions over the ice sheet. At the peak of the heatwave, an area of 3.3 million km2 in East Antarctica exceeded previous March monthly temperature records. Despite a temperature anomaly return time of about one hundred years, a closer recurrence of such an event is possible under future climate projections. In a subsequent manuscript, we describe the various impacts this extreme event had on the East Antarctic cryosphere.