In early 2022, alarming temperatures were observed on the Antarctic Peninsula (AP). Extremely high temperatures were recorded at several stations on the AP, reaching up to 13.7°C. At the same time, the most intense surface melting ever observed in this region occured. In their study, the researchers analysed the causes of these events using observational and modeling data.
During the extreme events, the northern/northwestern AP was affected by an intense atmospheric river (AR). These narrow, long bands form at lower latitudes and transport moisture and heat over thousands of kilometers to Antarctica. In 2022, this led to high precipitation, which fell not only as snow but also partly as rain.
In addition the heat had let to widespread snowmelt, which affected both the western and eastern AP.
A foehn effect (warm, dry downsloping winds) further increased temperatures on the northeast AP. Furthermore, various weather processes were taking place simultaneously, which together created ideal conditions for extreme melting. This is particularly critical, as repeated surface melting can weaken the ice shelf over time, making it more prone to breaking off.
In the context of climate change, rising summer temperatures of +0.15°C per decade were observed in the AP region between 1959-2021. As a warmer atmosphere can hold more moisture, climate change may increase the likelihood of these extreme events in Antarctica. ARs could occur even more severely or more frequently. Finally, long-term changes in Antarctic sea ice may, contribute to global sea-level rise.
This study highlights that Antarctica is not as isolated from the rest of the world as it may seem. Weather systems originating thousands of kilometers away from the remote continent can strongly influence Antarctic conditions. ARs are an important part of this connection, and understanding how they interact with Antarctic climate is essential for assessing future risks.
Source: Gorodetskaya, I.V., Durán-Alarcón, C., González-Herrero, S. et al. Record-high Antarctic Peninsula temperatures and surface melt in February 2022: a compound event with an intense atmospheric river. npj Clim Atmos Sci 6, 202 (2023).
Author: Oğuzhan
