| Summary: | In 2022, more snow fell across the Antarctic Ice Sheet (AIS) than in any previous year over at least the last four decades. As a result, the AIS surface mass balance (SMB), which accounts for both mass gains and losses at the ice sheet surface, was also at 40+ year highs and likely led to a net negative annual contribution of the ice sheet to global sea level. Here, we assess these SMB anomalies, calculated as total precipitation minus evaporation and sublimation, as well as their drivers using the ERA5 and MERRA2 global reanalyses. Both products indicate positive SMB anomalies of >300 Gt/yr in 2022 compared to the 1991-2020 climatological mean SMB, equating to 3.1 and 2.5 standard deviations above the respective long-term means. Annual anomalies were driven by positive monthly anomalies exceeding interannual variability in January, March, July, September, and November. In this presentation, we examine the spatial and temporal character of SMB variations and their linkages to concurrent anomalies in the atmosphere and Southern Ocean. We highlight the significant impacts of landfalling atmospheric rivers in specific sectors and months and assess the potential role of Southern Ocean surface forcing, which saw record low sea ice coverage for much of 2022. This work seeks to elucidate the drivers of SMB anomalies in 2022, which holds potential implications for understanding future AIS mass variations in a warming climate.
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