EO4GRHO seeks to push the boundaries of what types of information can be derived from EO datasets and explore how data from multiple satellites can support one another when analyzed together. Specific to Greenland

Kirk Scanlan is a researcher in the Geodesy & Earth Observation division of the National Space Institute (DTU Space) at the Technical University of Denmark. He has a strong background in the use of radar measurements in a variety of fields including earth science, geotechnical engineering, and planetary science. Kirk completed his undergraduate degree in Geophysics at Western University in London ON Canada in 2011 before pursuing his Master’s degree through the IDEA League Joint Master’s program in Applied Geophysics (finishing in 2013). Kirk then moved to the University of Alberta and the Department of Civil and Environmental Engineering where he pursued his Ph.D.

After completing his Ph.D. in 2018, Kirk began a postdoc at the University of Texas Institute for Geophysics working with the REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface) instrument to be carried on-board NASA’s Europa Clipper spacecraft to be launched in 2024. Since moving to DTU in 2021,
Kirk has been involved with the EU Horizon 2020 PROTECT project.

Research objectives

Global mean sea level rise over the 21st century has been and will continue to be strongly influenced by mass loss from the Greenland ice sheet. Critical to evaluating different climate change mitigation and adaption measures is an understanding of the rates at which this mass has been and will be lost. Satellite EO (Earth Observation) datasets provide a means to evaluating recent Greenland ice sheet mass change while models are used to project ice sheet evolution into the future. Firn densities across Greenland have a fundamental influence on ice sheet mass balance estimates derived from repeat satellite altimetry. They are the means of converting measured elevation changes to a mass change and assessing Greenland’s contribution to global mean sea-level rise. While conventionally based on sequential computational models of climatic conditions (i.e., temperature, precipitation etc.) and firn evolution (i.e., compaction, melting, refreezing, etc.), there is a growing body of work attempting to place observational constraints on how nearsurface densities across Greenland vary through time and space. Derived independently from either the strength of radar altimetry surface echoes or passive microwave brightness temperatures, these new observations contribute directly to
contemporary mass balance estimates as well as refinements to computational approaches for projecting mass balance into the future.
EO4GRHO proposes to synthesize satellite, airborne, and in situ measurements to observationally constrain how near-surface density varies with depth across Greenland through both time (monthly from 2013 to 2023) and space (pan-ice sheet). To do this, the project will first leverage multiple years of airborne Ku- and
Ka-band radar altimetry and LiDAR data over Greenland acquired as part of the ESA CryoVEx program to validate the existing interpretation of the space-based radar altimetry datasets (i.e., surface echo powers measured by the Ku-band CryoSat-2, Ku-band Sentinel-3, Ka-band SARAL satellites). Once validated, the near-surface insight garnered from the satellite radar altimetry datasets will be used to precondition the inversion of passive microwave measurements (i.e., SMOS brightness temperatures) to provide integrated assessment of the near-surface density profile. These observationally derived density profiles will then be compared against contemporaneous in situ measurements to validate the approach. EO4GRHO will not only produce a synthesized observational record of near-surface densities across Greenland that can be used to refine observed mass balance estimates and support the computational models used in ice sheet projection, but a framework for continuing these types of combined measurements with Europe’s next generations of EO satellites.

Broadly, EO4GRHO seeks to push the boundaries of what types of information can be derived from EO datasets and explore how data from multiple satellites can support one another when analyzed together. Specific to Greenland, EO4GRHO asks whether the joint analysis of active radar altimetry and passive microwave measurements can be used to recover a ten-year, pan-Greenland timeseries of nearsurface density; thereby providing new insight contributing to our understanding of global mean sea level rise.