Principal Investigator (PI): Eric Rignot, University of California, Irvine
The ice sheets in Antarctica and Greenland are contributing sooner and more significantly to sea level change than anticipated. To understand these changes and project the contribution of ice sheets to sea level change in the coming decades to centuries, it is essential to obtain comprehensive, continuous observations of ice sheet dynamics, which is the dominant vector of rapid sea level rise at present and in the future.
Our project addresses Antarctica and its 55-m sea level equivalent. We will employ a newly available, nearly continuous, multiple-sensor, satellite data stream of Antarctic observations from the USGS’s Landsat-8, ESA's (European Space Agency's) Sentinel-1A/B, Canadian Space Agency's RADARSAT-2, and other missions (Japanese Aerospace Exploration Agency's ALOS PALSAR-2 and Agenzia Spaziale Italiana's Cosmo Skymed) to produce new Earth Science Data Records (ESDRs) of:
- Monthly, ice-sheet wide, ice motion;
- a novel bed topography and ice thickness of Antarctica that conserves mass and fulfills the requirements of ice sheet models;
- annual maps of grounding line positions to document the dynamics of the land ice/floating ice boundaries around the continent;
- continued time series of ice-sheet-wide annual maps of ice motion; and
- revised land ice/floating ice/drainage boundaries since the 2007–2009 International Polar Year using newer constraints.
These ESDRs will be unique (bed topography and ice thickness), of higher quality (lower error bars), lower latency (every 4 months instead of annual), and with 12-time higher temporal resolution than in the past. The ESDRs will be generated using an automated chain of processing, extensively tested and vetted on prior projects that seamlessly ingests multi-sensor and multi-baseline data, and for which we eliminated risks. The new bed map, named BedMachine Antarctica, will be at an unprecedented level of spatial details (450 m posting) and precision (50-60 m) and the first Antarctic ice-sheet-wide product that merges with bathymetry products offshore and conserves mass on land, as needed for ice sheet modeling.
We demonstrated that methodology in Greenland and have the expertise and observational constraints to apply it to Antarctica. The monthly ice motion maps will document ice-sheet-wide changes in glacier activity, enabling a new generation of ice sheet models to assimilate a dense, comprehensive set of critical observations like never done before. The annual maps of grounding line positions will inform modelers about the most critical boundary between ocean and ice.
Using the newest digital elevation models of the ice sheet surface from Deutschen Zentrums für Luft- und Raumfahrt’s TanDEM-X in 2017 and the World View Reference Elevation Model of Antarctica (REMA) in 2018, a high-precision (15 cm/yr precision) map of ice motion using interferometric phase data from multiple satellites, airborne data from NASA’s Operation IceBridge (OIB), elevation change maps from NASA’s Ice, Cloud, and land Elevation (ICESat) and ICESat-2, ESA’s CryoSat-2, and output products from regional atmospheric climate models, we are updating existing drainage boundaries, sea level equivalence, ice front positions, and depth of subglacial channels occupied by ice streams across Antarctica for the scientific community.
Toward the end of the project, we will transition to generating ESDRs from the NASA-Indian Space Research Organization Synthetic Aperture Radar (NISAR) mission, effectively preparing ourselves and the community for this mission that will provide even greater access to observations of the ice sheets. These ESDRs will respond to critical needs from the modeling community and the broad scientific community interested in understanding the evolution of ice sheets and their contribution to sea level. The ESDRs will improve the capabilities of numerical models to project the future contribution of ice sheets to sea level rise and inform the public and policy makers. Overall, the project will serve NASA's Earth science goal to study the evolution of the Earth's ice masses and their impact on sea level change.