Sciences and Exploration Directorate

Joseph A MacGregor


Joseph A MacGregor's Contact Card & Information.
Phone: 301.614.5876
Org Code: 615
Mail Code 615
Greenbelt, MD 20771

Missions & Projects

Brief Bio

Joe MacGregor is a glaciologist and geophysicist interested in the past, present and future flow of ice sheets. He seeks to understand why ice sheets flow more quickly in some areas than in others, how this flow evolves over time and how we can better observe the controls upon ice flow. These are critical concerns for Earth’s two remaining ice sheets in Greenland and Antarctica, along with ice masses elsewhere in the Solar System. With a diverse set of collaborators at NASA and partner institutions, his current research synthesizes observations from a variety of methods, including airborne radar sounding (e.g., Operation IceBridge), satellite remote sensing (e.g., Landsat, MODIS, InSAR), ground-based surveys (e.g., ice core chemistry, borehole thermometry) and laboratory measurements (e.g., dielectric spectroscopy) to better understand ice sheets.


2008 - Ph.D., Geophysics, University of Washington (Seattle, WA)

2002 - B.S. with honors, Geophysical Engineering, Minor: Public Affairs for Engineers, Colorado School of Mines (Golden, CO)


Research Physical Scientist

Code 615, NASA GSFC - Greenbelt, MD

February 2016 - Present

Project Scientist, Operation IceBridge (OIB)

Cryospheric Sciences Laboratory (Code 615), NASA Goddard Space Flight Center (GSFC) - Greenbelt, MD

May 2018 - September 2021

Deputy Project Scientist, OIB

Code 615, NASA GSFC - Greenbelt, MD

March 2016 - May 2018

Research Associate

Institute for Geophysics, The University of Texas at Austin (UTIG) - Austin, TX

September 2013 - February 2016

Research Scientist Associate V

UTIG - Austin, TX

September 2011 - August 2013

Postdoctoral Fellow

UTIG - Austin, TX

October 2009 - August 2011

Research Associate

Dept. of Geosciences, The Pennsylvania State University - State College, PA

September 2008 - September 2009


  • 2022 - NASA GSFC HBG Peer Award for Best Publication – First Author Civil Servant
  • 2020 - Robert H. Goddard Award, Science Team (Operation IceBridge)
  • 2019 - Best Science Story, NASA GSFC SED Poster Party
  • 2017 - NASA 610 HBG Best Science Paper
  • 2013 - NASA Cryospheric Sciences Most Valuble Player
  • 2011 - UTIG Director's Circle of Excellence
  • 2008 - David A. Johnston Award for Research Excellence

Professional Service

Other Professional Information

Selected Publications


2024. "Geologic Provinces Beneath the Greenland Ice Sheet Constrained by Geophysical Data Synthesis." Geophysical Research Letters 51 (8): [10.1029/2023gl107357] [Journal Article/Letter]

2024. "Evidence for ca. 1 Ga hypervelocity impact event found in northwest Greenland." Geology [10.1130/g51876.1] [Journal Article/Letter]

2023. "Antarctic Bedmap data: FAIR sharing of 60 years of ice bed, surface and thickness data." Earth System Science Data 15 (7): 2695-2710 [10.5194/essd-2022-355] [Journal Article/Letter]

2023. "High mid-Holocene accumulation rates over West Antarctica inferred from a pervasive ice-penetrating radar reflector." The Cryosphere 17 [10.5194/tc-2022-199] [Journal Article/Letter]

2022. "Sixty years of ice form and flow at Camp Century, Greenland." Journal of Glaciology [10.1017/jog.2022.112] [Journal Article/Letter]

2022. "Drill-site selection for cosmogenic-nuclide exposure dating of the bed of the Greenland Ice Sheet." The Cryosphere 16 (10): 3933-3948 [10.5194/tc-16-3933-2022] [Journal Article/Letter]

2022. "GBaTSv2: A revised synthesis of the likely basal thermal state of the Greenland Ice Sheet." The Cryosphere [10.5194/tc-16-3033-2022] [Journal Article/Letter]

2022. "Greenland Geothermal Heat Flow Database and Map (Version 1)." Earth System Science Data 14 (5): 2209-2238 [10.5194/essd-14-2209-2022] [Journal Article/Letter]

2022. "A Late Paleocene age for Greenland’s Hiawatha impact structure." Science Advances 8 (10): [10.1126/sciadv.abm2434] [Journal Article/Letter]

2021. "Effect of ice sheet thickness on formation of the Hiawatha impact crater." Earth and Planetary Science Letters 566 116972 [10.1016/j.epsl.2021.116972] [Journal Article/Letter]

2021. "A first constraint on basal melt-water production of the Greenland ice sheet." Nature Communications 12 (1): 3461 [10.1038/s41467-021-23739-z] [Journal Article/Letter]

2021. "Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers." The Cryosphere 15 (6): 2569-2574 [10.5194/tc-15-2569-2021] [Journal Article/Letter]

2021. "Radar‐Sounding Characterization of the Subglacial Groundwater Table Beneath Hiawatha Glacier, Greenland." Geophysical Research Letters 48 (10): [10.1029/2020gl091432] [Journal Article/Letter]

2021. "The scientific legacy of NASA's Operation IceBridge." Reviews of Geophysics (59): e2020RG000712 [10.1029/2020rg000712] [Journal Article/Letter]

2021. "Topographic Correction of Geothermal Heat Flux in Greenland and Antarctica." Journal of Geophysical Research: Earth Surface 126 (2): [10.1029/2020jf005598] [Journal Article/Letter]

2021. "Microwave Radiometry at Frequencies from 500 to 1400 MHz: An Emerging Technology for Earth Observations." IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 1-1 [10.1109/jstars.2021.3073286] [Journal Article/Letter]

2020. "Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift." Journal of Geophysical Research: Earth Surface 125 (12): [10.1029/2020jf005775] [Journal Article/Letter]

2020. "The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet." Journal of Glaciology 66 (258): 667-684 [10.1017/jog.2020.62] [Journal Article/Letter]

2019. "A Possible Second Large Subglacial Impact Crater in Northwest Greenland." Geophysical Research Letters 46 [10.1029/2018gl078126] [Journal Article/Letter]

2019. "New Estimates of Ice and Oxygen Fluxes Across the Entire Lid of Lake Vostok from Observations of Englacial Radiowave Attenuation." Journal of Geophysical Research: Earth Surface 124 [10.1029/2018jf004692] [Journal Article/Letter]

2019. "Possible Role for Tectonics in the Evolving Stability of the Greenland Ice Sheet." Journal of Geophysical Research: Earth Surface 124 [10.1029/2018jf004714] [Journal Article/Letter]

2018. "A large impact crater beneath Hiawatha Glacier in northwest Greenland." Science Advances 4 (11): eaar8173 [10.1126/sciadv.aar8173] [Journal Article/Letter]

2017. "Inter-comparison of snow depth retrievals over Arctic sea ice fromradar data acquired by Operation IceBridge." The Cryosphere 2571-2593 [10.5194/tc-2017-103] [Journal Article/Letter]

2017. "How much, how fast?: A science review and outlook for research on the instability of Antarctica's Thwaites Glacier in the 21st century." Global and Planetary Change 153 16-34 [10.1016/j.gloplacha.2017.04.008] [Journal Article/Letter]

2016. "Annual Greenland accumulation rates (2009–2012) from airborne Snow Radar." The Cryosphere 10 1739–1752 [10.5194/tcd-9-6697-2015] [Journal Article/Letter]

2016. "The abandoned ice-sheet base at Camp Century, Greenland, in a warming climate." Geophysical Research Letters 43 [10.1002/2016GL069688] [Journal Article/Letter]

2016. "A synthesis of the basal thermal state of the Greenland Ice Sheet." J. Geophys. Res. Earth Surf. 121 [10.1002/2015jf003803] [Journal Article/Letter]

2016. "Deep radiostratigraphy of the East Antarctic plateau: connecting the Dome C and Vostok ice core sites." J. Glaciol. 1-12 [10.1017/jog.2016.11] [Journal Article/Letter]

2016. "Holocene deceleration of the Greenland Ice Sheet." Science 351 (6273): 590-593 [10.1126/science.aab1702] [Journal Article/Letter]

2015. "Dielectric signatures and evolution of glacier ice." Journal of Glaciology 61 (230): 1159-1170 [10.3189/2015jog15j113] [Journal Article/Letter]

2015. "Radar attenuation and temperature within the Greenland Ice Sheet." J. Geophys. Res. Earth Surf. 120 (6): 983-1008 [10.1002/2014jf003418] [Journal Article/Letter]

2015. "What Instruments are Available for Polar Studies?." Eos 96 [10.1029/2015EO026855] [Journal Article/Letter]

2015. "Radiostratigraphy and age structure of the Greenland Ice Sheet." J. Geophys. Res. Earth Surf. 120 (2): 212-241 [10.1002/2014jf003215] [Journal Article/Letter]

2013. "Weak bed control of the eastern shear margin of Thwaites Glacier, West Antarctica." Journal of Glaciology 59 (217): 900-912 [10.3189/2013jog13j050] [Journal Article/Letter]

2013. "Electrical response of ammonium-rich water ice." Annals of Glaciology 54 (64): 21-26 [10.3189/2013aog64a204] [Journal Article/Letter]

2013. "The role of acids in electrical conduction through ice." J. Geophys. Res. Earth Surf. 118 (1): 1-16 [10.1029/2012jf002603] [Journal Article/Letter]

2012. "Predicting radar attenuation within the Antarctic ice sheet." Earth and Planetary Science Letters 359-360 173-183 [10.1016/j.epsl.2012.10.018] [Journal Article/Letter]

2012. "Spatial variation of englacial radar attenuation: Modeling approach and application to the Vostok flowline." Journal of Geophysical Research: Earth Surface 117 (F3): [10.1029/2011jf002327] [Journal Article/Letter]

2012. "Widespread rifting and retreat of ice-shelf margins in the eastern Amundsen Sea Embayment between 1972 and 2011." Journal of Glaciology 58 (209): 458-466 [10.3189/2012jog11j262] [Journal Article/Letter]

2011. "The grounding zone of the Ross Ice Shelf, West Antarctica, from ice-penetrating radar." Journal of Glaciology 57 (205): 917-928 [Journal Article/Letter]

2009. "Spatial variation of radar-derived basal conditions on Kamb Ice Stream, West Antarctica." Annals of Glaciology 50 (51): 10-16 [10.3189/172756409789097504] [Journal Article/Letter]

2009. "Radar detection of accreted ice over Lake Vostok Antarctica." Earth Planet Sci Lett 282 (1-4): 222-233 [10.1016/j.epsl.2009.03.018] [Journal Article/Letter]

2009. "Millennially averaged accumulation rates for the Lake Vostok region inferred from deep internal layers." Annals of Glaciology 50 (51): 25-34 [Journal Article/Letter]

2007. "Modeling englacial radar attenuation at Siple Dome, West Antarctica, using ice chemistry and temperature data." Journal of Geophysical Research 112 (F3): F03008 [10.1029/2006jf000717] [Journal Article/Letter]

2005. "Modeling the natural degradation of earthworks." Geoarchaeology 20 (7): 739-748 [10.1002/gea.20079] [Journal Article/Letter]


2021. "Solar-System-Wide Significance of Mars Polar Science." Vol. 53, Issue 4 (Planetary/Astrobiology Decadal Survey Whitepapers) 53 (4): [10.3847/25c2cfeb.4db95c67] [Other]

2014. "Cryosphere: Bottom-up restructuring of ice." Nature Geosci 7 (7): 481-482 [10.1038/ngeo2191] [Journal Article/Letter]


Greenland-scape: Uncovering topography and geology beneath the Greenland Ice Sheet - NASA Earth Surface and Interior - Awarded: 2003-01-23

Dates: 2003-01-23

Calibrated sensitivity of the Greenland Ice Sheet to major climate changes from next-generation radiostratigraphy and ensemble modeling - NASA Cryospheric Sciences - Awarded: 0000-00-00

Dates: 2021-01-01  - 2023-12-31

Reconnaissance of the ice margin near the Hiawatha impact crater - NASA Goddard Fellows Innovation Challenge - Awarded: 2019-03-01

Dates: 2019-03-01  - 2019-09-30

A peek into the history of the Greenland Ice Sheet using radar layers and modeling - NASA Cryospheric Science - Awarded: 2016-01-01

Dates: 2016-01-01  - 2018-12-31

New estimates of the oxygen flux into, and its distribution within, Lake Vostok using radar sounding observations - NASA Habitable Worlds - Awarded: 2015-01-01

Dates: 2015-01-01  - 2017-12-31

Accumulation and flow of the Greenland Ice Sheet during the late Holocene - NASA IceBridge Research - Awarded: 2015-01-01

Dates: 2015-01-01  - 2017-12-31

Partitioning of soluble impurities in ice: A foundation for planetary radar exploration - NASA Planetary Geology & Geophysics - Awarded: 2014-01-01

Dates: 2014-01-01  - 2016-12-31

Accumulation and flow of the Greenland Ice Sheet during the Anthropocene - UT Jackson School of Geosciences Seed Grant Program - Awarded: 2014-01-01

Dates: 2014-01-01  - 2014-12-31

A synthetic approach to mapping the thermal state of the bed of the Greenland Ice Sheet and critical boundary conditions for the next generation of ice-sheet models - NASA IceBridge Research - Awarded: 2012-01-01

Dates: 2012-01-01  - 2014-12-31

Collaborative Research: A new radiostratigraphy of the Greenland Ice Sheet and critical boundary conditions for the next generation of ice-sheet models - NSF Arctic Natural Sciences - Awarded: 2012-01-01

Dates: 2012-01-01  - 2014-12-31

New broadband measurements of the dielectric properties of ice cores: A foundation for planetary radar sounding - NASA Planetary Geology & Geophysics - Awarded: 2010-01-01

Dates: 2010-01-01  - 2012-12-31

Selected Public Outreach

A possible second large subglacial impact crater in northwest Greenland

March 2019 - March 2019

NASA SVS animation contextualizing second possible impact crater in northwest Greenland.

Massive Crater Discovered under Greenland Ice

December 2018 - December 2018

NASA collaborative production describing the discovery of the Hiawatha impact crater.

Greenland Ice Sheet stratigraphy

2015 - 2015

NASA SVS animation illustrating collection, tracing and dating of Greenland's internal stratigraphy.

Professional Societies

American Geophysical Union

2002 - Present

International Glaciological Society

2002 - Present