[A-AS06] Atmospheric (Stratosphere-troposphere) Processes And their Role in Climate

[AAS06-P10] Deepened and Eastward-Shift of the Amundsen Sea Low Contributes to Recent Antarctic Peninsula Mass Accumulation

*Zhen Li¹, Benjamin Fong Chao² (1.Innovation Academy of Precision Measurement of Science and Technology, Chinese Academy of Sciences, 2.College of Geodesy and Geomatics, Shandong University of Science and Technology)

Keywords:Amundsen Sea Low, GRACE, ICESAT-2, Antarctic Peninsula, Water Vapour Transportation

After over two decades of persistent negative mass balance, the Antarctic Peninsula has experienced unprecedented mass accumulation since 2021, however the underlying causes are still yet to be understood. Using GRACE (Gravity Recovery and Climate Experiment), ICESat-2 (Ice, Cloud and land Elevation Satellite-2) and meteorological reanalysis data, we analyze the recent mass accumulation in the Antarctic Peninsula and its climatic drivers. From Jan. 2021 to Dec. 2023, GRACE recorded a mass accumulation of 72.5 Gt or a rate of 25.1 Gt/yr, while ICESat-2 measured an average surface elevation increase of 16.1 cm/yr, because of the increased precipitation. We find that changes in Amundsen Sea Low (ASL) are the primary drivers of the recent mass accumulation, which explains about 60% of the variability in precipitation anomaly. The deepened and eastward shift of the ASL, relative to La Niña event, results in stronger and more frequent northerly winds, enhancing the transport of warm, moist airflows towards the Antarctic Peninsula, ultimately leading to increased precipitation. Our findings provide crucial insights into the Antarctic Peninsula mass balance response to atmospheric circulation anomalies.