Keegan

Research

We investigate the processes underlying snow, firn, and ice evolution to better understand important glaciological applications, such as the interpretation of ice core paleoclimate records, monitoring ice-mass balance from satellite altimetry, and assessing an ice sheet’s capacity to retain meltwater in firn aquifers.

Active Research Projects

Firn Microstructure

The microstructure of firn impacts densification processes and pore space evolution in the firn column. We use X-ray micro-computed tomography (micro-CT) and topological data analysis (TDA) methods to quantify the microstructural properties of firn and their evolution in the firn column at varying sites. Through this work, we identify robust methods for retrieving microstructure data from micro-CT images.

Firn Compaction at Taylor Dome

We are heading to Taylor Dome, Antarctica, to study firn compaction and microstructure evolution at sites across the dome’s accumulation gradient. Detailed firn measurements at these sites will allow us to untangle the impact of the accumulation gradient on firn properties from that of temperature. Insights from this work will aid in the development of a physics-based firn compaction model.

Meltwater Storage in Firn

Meltwater generated at the surface of an ice sheet can percolate into the open porosity of firn. In colder conditions, the meltwater will refreeze into ice lenses within the firn, while in some warmer conditions, the meltwater can remain liquid water, filling the open pore space. We investigate the role of firn microstructure on the fate of meltwater on an ice sheet.

Publications

Horlings, B. I., Courville, Z., Murdza, Andrii, and Keegan, K. (2025), Applicability of two-phase modeling with compression experiments for snow compaction dynamics, Cold Regions Science and Technology, Vol 229. doi: 10.1016/j.coldregions.2024.104336

McDowell, I.E., Keegan, K., Skiles, S.M.K., Donahue, C.P., Osterberg, E.C., Hawley, R.L., Marshall, H-P (2024), A cold laboratory hyperspectral imaging system to map grain size and ice layer distributions in firn cores, The Cryosphere, 18(4), 1925-1946. doi: 10.5194/tc-18-1925-2024

The Firn Symposium Team (2024), Firn on ice sheets, Nature Reviews Earth Environs, 5, 79-99. doi: 10.1038/s43017-023-00507-9

Li, Y., Fu, C., Keegan, K., Yang, J., Huang, G., Baker, I. (2023), “Microstructural characterization of depth hoar and ice-crust layers using a micro-CT, and hypothesis of ice-crust formation under a thunderstorm,” Hydrological Processes, 37(12), e15060. doi: 10.1002/hyp.15060

McDowell, I.E., Keegan, K., Wever, N., Osterberg, E.C., Hawley, R.L., Marshall, H-P (2023), “Firn Core Evidence of Two-Way Feedback Mechanisms Between Meltwater Infiltration and Firn Microstructure From the Western Percolation Zone of the Greenland Ice Sheet,” Journal of Geophysical Research Earth Surface, 128(2), e2022JF006752. doi: 10.1029/2022JF006752

Lawson, A., Hoffman, T., Chung, Y-M, Keegan, K., Day, S. (2022), A density-based approach to feature detection in persistence diagrams for firn data, Foundations of Data Science, 4(4), 623-639. doi: 10.3934/fods.2021012

Keegan, K. (2022), Snow metamorphism and firn compaction, Treatise on Geomorphology (2nd Edition), 4, 39-51. doi: 10.1016/B978-0-12-818234-5.00041-9

Hu, C-S, Lawson, A., Chung, Y-M, Keegan, K. (2021), Two-Parameter Persistence for Images via Distance Transform, Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV) Workshops, 4176-4184.

Belotti, V., Jester, M. Keegan, K., Chung, Y-M, Day, S. (2021), Topological Estimation of 2D Image Data via Subsampling and Application to Firn, IEEE Access, 9, 10348-10356. doi: 10.1109/ACCESS.2021.3050377

McDowell, I.E., Albert, M.R., Lieblappen, S.A., and K.M. Keegan (2020), Local Weather Conditions Create Structural Differences between Shallow Firn Columns at Summit, Greenland and WAIS Divide, Antarctica, Atmosphere, 11, 1370. (link)

Meyer, C.R., K.M. Keegan, I. Baker, and R.L. Hawley (2020), A model for French-press experiments of dry snow compaction, The Cryosphere, 14, 1449-1458, doi: 10.5194/tc-14-1449-2020. (link)

Keegan, K.M., M.R. Albert, J. McConnell, and I. Baker (2019), Climate effects on firn permeability are preserved within a firn column, Journal of Geophysical Research: Earth Surface, 124, 830-837. (link)

Keegan, K.M., M.R. Albert, J. McConnell, I. Baker (2014), Climate change and forest fires synergistically drive widespread melt of the Greenland Ice Sheet, Proceedings of the National Academy of Sciences of the United States of America, 111:7964-7967. (link)

Keegan, K.M., M.R. Albert, and I. Baker (2014), The impact of ice layers on gas transport through firn at the North Greenland Eemian Ice Drilling (NEEM) site, Greenland, The Cryosphere, 8:1801-1806. (link)

Dahl-Jensen, D., M.R. Albert, A. Aldahan… K.M. Keegan… (many authors, listed alphabetically) (2013), Eemian interglacial reconstructed from a Greenland folded ice core, Nature 493:489-494. (link)

 S. V. Nghiem, D. K. Hall, T. L. Mote, M. Tedesco, M. R. Albert, K. Keegan, C. A. Shuman, N. E. DiGirolamo, G. Neumann(2012), The extreme melt across the Greenland ice sheet in 2012, Geophysical Research Letters 39, L20502, doi:10.1029/2012GL053611. (link)

Current Lab Members

Kaitlin Keegan (PI)

I’m fascinated by paleoclimate records and what they can tell us about Earth’s climate in the past and also how it may change in the future. I study the structure of snow, firn, and ice to help interpret the climate records that come from ice.

Contact: kkeegan@unr.edu

CV

Dylen Swan (MS Student)

Dylen is investigating impact of accumulation rate on firn compaction and evolution at Taylor Dome, Antarctica. Outside of research, some of her hobbies include attending concerts/festivals, skiing, slacklining, hula-hooping, paddleboarding, and climbing.

Samantha Regalado (Undergraduate)

Sami is an undergraduate student in the Materials Science & Engineering department at UNR, and is working on quantifying firn microstructure complexity.

Lab Alumni

Contact

You can contact the Keegan Lab at kkeegan@unr.edu or by submitting a comment in the box below.