Collaborative Research: Combined Impact of Atmospheric Rivers and Foehn Warming on the Surface Warming/Melting over West Antarctica - Standard Grant

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

Atmospheric rivers are narrow atmospheric corridors transporting significant moisture from the subtropics to higher latitudes. In Antarctica, these features are thought to influence ice mass balance by inducing surface melt through increasing air temperatures while counteracting melt through increased snowfall. The recently-identified positive trend in atmospheric river activity and summer surface melting in West Antarctica highlight the need to study these extreme weather events. Better predictions of atmospheric river impacts on glaciers and ice shelves will improve projections of Antarctic ice mass balance and global sea level rise, critical for coastal communities living at low- and mid-latitudes. Additionally, this research will include undergraduate students in studies of Antarctic extreme weather events, develop a public, real-time forecast tool to assist fieldwork planning and other operational activities, and provide educational seminars on climate change to students from community colleges. This research will utilize new, high-resolution numerical weather prediction simulations and existing satellite and ground observations to investigate Atmospheric River (AR)-associated extreme weather events over West Antarctica. Detailed physical mechanisms will be examined through trajectory analysis, tracking the moisture source of ARs, heat exchange along their paths, and their overall contribution to surface warming and melting. Additionally, the study will analyze cloud formation and radiative impacts associated with AR intrusions, as well as AR-related mountain meteorology. Researchers will test whether the abundant moisture from AR intrusions, accompanied by low-level jets (strong winds) during austral summers, leads to intense rainfall along the coast of West Antarctica and rapid warming on the leeward side of mountain ranges, as exemplified by the extensive surface melting event over the eastern Ross Ice Shelf in January 2016. This research will elucidate the impacts of ARs on the ice surface from a surface energy balance perspective and provide us with a more accurate estimation of surface melting in West Antarctica. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.