Related Research Areas
Climate Variability & Change, Earth Surface & Interior, Water & Energy Cycles

The central objective of this project is to validate ice-sheet surface elevation retrievals from the ESA mission CryoSat-2. CryoSat-2 will fly a new type of radar altimeter, which uses synthetic aperture processing in the along-track direction and interferometric processing in the across-track direction in order to overcome some of the principal limitations of conventional radar altimeters. No single project can completely validate the retrievals from all parts of the ice sheet; rather, this individual project will be a key component in the international collaborative effort to ensure that the elevations retrieved by CryoSat-2 reflect the physical reality at the surface. This project takes on 2 key issues involving the performance of the radar altimeter over ice sheets: 1) increasing the density of elevation points retrieved in the steep, rapidly changing margins of the ice sheets, and 2) understanding how density, grain size, and snow morphology control penetration of the radar signal into near-surface snow and firn and generate subsurface echoes in the dry interior of the large ice sheets. This project will undertake to accomplish these goals through establishment and verification of a new methodology for processing interferometric radar altimeter data, and a data-driven campaign to: 1) determine and verify ice-sheet elevations at the margins and interior of the Greenland Ice Sheet, 2) identify and interpret ``swath-like'' altimeter returns in SIRAL Level 1B data, and 3) identify and interpret subsurface echoes in SIRAL data. Both phenomena have been observed in preliminary airborne interferometric radar altimeter data. This project is significant to the Earth Science Community, the Earth Observing community, and the population at large. In particular this project addresses NASA's strategic goals 1) "How is the global Earth system changing" through enabling monitoring of the ice sheets, 3) "How does the Earth system respond to natural and human-induced changes?" because the ice sheets are responding to both natural forcings and also anthropogenic ones, and 4) "What are the consequences for human civilization?" by providing a better understanding of the geometry of the Greenland Ice Sheet, which will lead to better predictions of the impact Greenland melting will have for human civilization. This project will also help answer NASA key Science Questions- to: 4) "Quantify the key reservoirs and fluxes in the global water cycle and improve models of water cycle change and fresh water availability: and 5) "Understand the role of oceans, atmosphere, and ice in the climate system and improve predictive capability for its future evolution"

Project PI: Robert Hawley/Dartmouth College

Department of Earth Sciences Dartmouth College 6105 Fairchild Hall Hanover, NH 03755

Phone: (603) 646-2373

Fax: (603) 646-3922



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Started: Sep 27, 2010

Last Activity: Jan 04, 2011


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