- 1Ca' Foscari University of Venice, Department of Environmental Science, Informatics and Statistics, Venice, Italy (giuliano.dreossi@unive.it)
- 2ENEA, Laboratory of Models and Measurements for Air Quality and Climate Observations, Rome, Italy
- 3Institute of Atmospheric Sciences and Climate, National Research Council of Italy (INO-CNR), Bologna, Italy
- 4LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
- 5Geophysical Institute, University of Bergen, Bjerknes Centre for Climate Research, Bergen, Norway
- 6International Atomic Energy Agency, Department of Nuclear Science and Applications, Division of Physical and Chemical Sciences, Isotope Hydrology Section, Vienna, Austria
An unprecedented heatwave affected East Antarctica between 15 and 19 March 2022, triggering record-high temperatures from the coastal regions to the Antarctic plateau. The event was caused by an intense atmospheric river that transported heat and moisture from the central and southwestern subtropical Indian Ocean at lower latitudes into the interior of continental Antarctica. Although the poleward moisture advection ceased after 18 March, a counterclockwise flow of clouds around a blocking anticyclone trapped the residual moisture over Antarctica. This led to sustained high surface temperatures for several days following the atmospheric river event (Wille et al., 2024a).
The heatwave brought rain and caused significant surface melting in coastal areas and intense snowfall events in the inner Antarctic region, which contributed to an overall positive mass balance. The Italian stake farm close to Concordia Station observed an accumulation of ~7 cm from 15 February to 22 March, which represents almost 90% of the local amount of accumulation.
Although the March 2022 heatwave lasted only for some days, model results suggest that this anomaly can be retrieved from ice core records over the equivalent of several years of snow accumulation (Wille et al., 2024b).
Since 2008, daily precipitation has been collected at Concordia Station, East Antarctica. The snow collected during the March 2022 heatwave exhibits δ¹⁸O and δ²H values that are the highest recorded since precipitation collection began. On 9 January 2023, a high-resolution snow pit, sampled at 2 cm intervals, was dug at Concordia. The isotopic analysis revealed a significant peak between 12 and 16 cm in depth, with three δ¹⁸O values exceeding -40‰. These unusually high values can be directly linked to the precipitation from the March 2022 heatwave.
The oceanic origin of the water vapor was also observed in tritium (3H) levels: in the Dome C 2022 precipitation reconnaissance measurements, values were as low as 10 TU (compared to between 20 and 400 TU during the rest of the year), which is in good agreement with GNIP observation sites closer to the Antarctic coast at similar latitudes.
Understanding the effects of single heatwave events on the isotopic signal stored in snow, firn and in ice cores is fundamental to better constrain palaeoclimatological studies, where isotopic analysis is widely used in climate reconstruction studies.
Wille, J. D., and Coauthors, 2024a. https://doi.org/10.1175/JCLI-D-23-0175.1
Wille, J. D., and Coauthors, 2024b. https://doi.org/10.1175/JCLI-D-23-0176.1
How to cite: Dreossi, G., Masiol, M., Zannoni, D., Stefanini, C., Scarchilli, C., Ciardini, V., Grigioni, P., Del Guasta, M., Landais, A., Casado, M., Ollivier, I., Terzer-Wassmuth, S., Copia, L., and Stenni, B.: March 2022 warm event detected in precipitation and surface snow at Concordia Station in East Antarctica, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19112, https://doi.org/10.5194/egusphere-egu25-19112, 2025.
