The Scientific Legacy of NASA’s Operation IceBridge

The National Aeronautics and Space Administration (NASA)’s Operation IceBridge (OIB) was a 13-year (2009–2021) airborne mission to survey land sea ice across the Arctic, Antarctic, Alaska. Here, we review OIB’s goals, instruments, campaigns, key scientific results, implications for future investigations of cryosphere. primary goal use laser altimetry bridge gap in fine-resolution elevation measurements from space between conclusion NASA’s Ice, Cloud, Elevation Satellite (ICESat; 2003–2009) its follow-on, ICESat-2 (launched 2018). Additional requirements were intended contextualize observed changes using multisensor suite radar sounders, gravimeters, magnetometers, cameras. Using 15 different aircraft, OIB conducted 968 science flights, which 42% repeat surveys ice, previously unmapped terrain Greenland Antarctic sheets, Arctic caps, Alaskan glaciers, 16% ice. combination an expansive instrument breadth enabled numerous fundamental advances our understanding Earth’s For dramatically improved knowledge interannual outlet-glacier variability, ice-sheet, thicknesses, snowfall rates on fjord sub-ice-shelf bathymetry, ice-sheet hydrology. Unanticipated discoveries included reliable method constraining thickness within difficult-to-sound incised troughs beneath extent firn aquifer Ice Sheet, vulnerability many outlet glaciers ocean-driven melting at their grounding zones, dominance surface-melt-driven mass loss glaciers. significantly advanced spatiotemporal variability freeboard snow cover, especially through combined analysis altimetry, visible imagery, overlying thickness. Such analyses led unanticipated discovery interdecadal decrease opportunities validate freeboards satellite altimetry. While data sets have yet be fully explored, legacy has already demonstrated value sustained investment platforms, development, interagency international collaboration, open rapid access advance remote polar regions role Earth system.