Antarctic Atmospheric Rivers in the Present and Future Climates

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• Dr. Michelle Maclennan, British Antarctic Survey
• Thursday 27 February 2025, 16:00-17:00
• Scott Polar Research Institute, main lecture theatre.

If you have a question about this talk, please contact rld46.

Despite occurring only ~1% of the time, Antarctic atmospheric rivers (ARs) contribute 10% of the annual precipitation and are major drivers for heatwaves, foehn events, and surface melting on ice shelves. While snowfall is currently the dominant impact of ARs on Antarctica, the relative contribution of ARs to snowfall, rainfall, and surface melt may change in a warming climate, along with the frequency and intensity of AR events themselves. Here, we use a suite of global climate models, including the Community Earth System Model version 2 (CESM2) Large Ensemble and the US Department of Energy’s Exascale Earth System Model version 2 (E3SMv2), to detect ARs during the current period (1980–2014) and future climate (2015–2100) under the SSP370 radiative forcing scenario. We use an AR detection threshold for the current period based on the 98th percentile of the meridional component of integrated vapor transport (vIVT). To account for projected future increases in atmospheric moisture content (Clausius-Clapeyron effect) and its impacts on vIVT, we scale our AR detection threshold for the future period by the relative change in integrated water vapor compared to the present-day climatology. We then describe how the frequency and variability of Antarctic ARs changes by the end of the 21st century by region, with links to changes in the large-scale atmospheric circulation accompanying ARs. Finally, we quantify AR-attributed precipitation, precipitation variability, and trends in the future climate, ultimately providing an early assessment of future AR-driven changes to Antarctic surface mass balance.

This talk is part of the Scott Polar Research Institute - Polar Physical Sciences Seminar series.

This talk is included in these lists:

• AUB_Cambridge Seminars
• Climate Science Seminars within Cambridge
• Department of Geography
• Scott Polar Research Institute - Polar Physical Sciences Seminar
• Scott Polar Research Institute, main lecture theatre
• seminars

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