This event occurred on August 4, 2024

Consisting of a massive ice sheet plateau rising to over 4000 meters above sea level, East Antarctica is home to the coldest average temperatures on Earth. Although winter temperatures on the East Antarctic Plateau do not currently reach the freezing point, during the late austral winter of 2024, temperatures soared to highly unusual values. Observations archived by the University of Wisconsin-Madison Antarctic Meteorological Research and Data Center (AMRDC) show that warming peaked from 4–5 Aug 2024, when Mizuho Station (2260m elevation) reached -12.4$\degree$C, and Relay Station (3353m) reached -23.9$\degree$C.

The animation below shows that both PREFIRE satellites frequently sampled the extreme “heat dome” over East Antarctica and the plumes of atmospheric moisture along its flanks. Zhai et al. (2025) found that these blocking high pressure systems and atmospheric rivers mutually reinforced one another throughout the late winter to force the warmest July–August period over the East Antarctic Ice Sheet since at least the 1950s.

PREFIRE-SAT2 began science data collection in late June 2024. This provides observations from the full austral winter of 2025, plus July–August 2024, to provide context for the late winter 2025 warm event. The map below shows the location of the warmest PREFIRE-SAT2 spectrum collected over the East Antarctic plateau during this event.

The plot below compares this spectrum to all PREFIRE-SAT2 spectra collected over the East Antarctic Plateau to date during austral winter (July–Aug 2024, June–Aug 2025). In most of the mid-infrared (~9–14 µm) and far-infrared (~16–30 µm) spectral region where PREFIRE-SAT2 currently provides highest-quality L1B data, this was the most top-of-atmosphere radiance observed by PREFIRE-SAT2 over the East Antarctica Plateau during winter. The large gap between this spectrum and the 99th percentile of all other East Antarctic Plateau winter spectra illustrates the extreme nature of this warm event.

Integrating the measured radiance across all spectral channels, the 2B-FLX product provides top-of-atmosphere outgoing longwave radiation (OLR) across the full infrared spectrum for each PREFIRE footprint. Comparing the distribution of OLR over the East Antarctic Plateau from PREFIRE-SAT2 on 4 Aug 2024 to all values during austral winter (below) provides another perspective on this extreme event. The strong rightward shift of the OLR distribution on this date, with values in the tail (exceeding 200 W m^-2) that are exceedingly rare in the PREFIRE record thus far, indicates that the coupled Earth-atmosphere system responded to the extreme intrusion of heat and moisture into the Antarctic by emitting correspondingly extreme amounts of infrared energy to space.

By measuring emitted radiation at the top of the atmosphere across the full mid- and far-infrared spectral range, PREFIRE provided a unique perspective on the unprecedented heat wave over East Antarctica during late winter 2024. PREFIRE continues to collect new observations that will build up a longer data record for placing these extreme events in context.