William Colgan, Ph.D.
I am a research climatologist. I study glaciers as indicators of climate change using computer simulations, satellite observations and field measurements. I received my Ph.D. in Geography from the University of Colorado in 2011.
In the past five years I have worked in government-, university- and private-sector settings in the United States, Denmark and Canada. I value communicating climate science via both social and conventional media. This is my personal website.
My research has three main themes: computer simulations of ice form and flow, satellite observations of glacier and ice sheet mass balance and glacier-related geotechnical or geophysical challenges. I perform fieldwork in support of each of these themes, such as maintaining automatic weather stations to collect local small data against which to evaluate the big data of satellite observations and computer simulations.
Although people tend to think of ice as a solid object, it actually behaves as a fluid, flowing like an extremely viscous river on geological timescales. My computer simulations of thermo-mechanical ice flow are both hypothesis-based, like diagnostic simulations seeking to reproduce observed behaviour from first-principles physics, and objective-based, like prognostic simulations seeking to estimate future sea level rise contribution (11,28,33).
There are three main ways that satellites can assess the health of land ice: volume changes measured by satellite altimetry, mass changes inferred by satellite gravimetry and differencing satellite-inferred iceberg discharge from simulated net snowfall rate. I mainly focus on blending coincident satellite altimetry and gravimetry observations, to overcome their complementary weaknesses, but I am also interested in pre-satellite mass balance (16,23,29).
My applied glaciology research examines the unique geotechnical or geophysical challenges associated with human activites on, or adjacent to, glaciers in the context of impact assessment. These challenges include supraglacial runoff and en-/sub-glacial water flow, ice movement beneath infrastructure or into excavations, and crevasse hazards. My applied glaciology research to date has focused on prospective industrial projects and abandoned military bases (17,22,39).
I have documented over 300 expedition days, from the Arctic to the Antarctic, as a hobby photographer. Although glacier and ice sheet field work is inherently photogenic, it can be rather hostile to camera equipment. I maintain a Picasa album of some of my favourite field photographs. Please contact me for media use.
I value deliberate efforts to communicate climate change science to the broader public. I think outreach activities are critical to fostering citizen science, or public participation in scientific research, and ultimately increasing the democratization of science. I maintain a Twitter account for transmitting and receiving climate change science, and I occassionally blog about my research.
I have lead-authored 16, and co-authored a further 23, peer-reviewed publications since 2008. I am a strong supporter of journals published by professional societies, as well as the movement of peer-reviewed papers to open access format. I maintain a GoogleScholar profile, which tracks my research citations and recent collaborators.
39. W. Colgan, H. Machguth, M. MacFerrin, J. Colgan, D. van As and J. MacGregor. 2016. The abandoned ice-sheet base at Camp Century, Greenland, in a warming climate. Geophysical Research Letters. 43: 8091-8096. [web] [.pdf]
38. J. MacGregor, M. Fahnestock, G. Cantania, A. Aschwanden, G. Clow, W. Colgan, S. Gogineni, M. Morlighem, S. Nowicki, J. Paden, S. Price and H. Seroussi. 2016. A synthesis of the basal thermal state of the Greenland Ice Sheet. Journal of Geophysical Research. 121: 1328-1350. [web] [.pdf]
37. H. Machguth, H. Thomsen, A. Weidick, J. Abermann, A. Ahlstrøm, M. Andersen, S. Andersen, A. Bjørk, J. Box, R. Braithwaite, C. Bøggild, M. Citterio, P. Clement, W. Colgan, R. Fausto, K. Gleie, B. Hasholt, B. Hynek, N. Knudsen, S. Larsen, S. Mernild, J. Oerlemans, H. Oerter, O. Olesen, C. Smeets, K. Steffen, M. Stober, S. Sugiyama, D. van As, M. van den Broeke and R. van de Wal. 2016. Greenland surface mass-balance observations from the ice sheet ablation area and local glaciers. Journal of Glaciology. 62: 861-887. [web] [.pdf]
36. C. Charalampidis, D. van As, W. Colgan, R. Fausto, M. MacFerrin and H. Machguth. 2016. Thermal tracing of retained meltwater in the lower accumulation area of the Southwestern Greenland ice sheet. Annals of Glaciology. 57: 1-10. [web] [.pdf]
35. R. Fausto, D. van As, J. Box, W. Colgan, P. Langen and R. Mottram. 2016. The implication of nonradiative energy fluxes dominating Greenland ice sheet exceptional ablation area surface melt in 2012. Geophysical Research Letters. 43: 2649-2658. [web] [.pdf]
34. W. Colgan, H. Rajaram, W. Abdalati, C. McCutchan, R. Mottram, M. Moussavi and S. Grigsby. 2016. Glacier Crevasses: Observations, Models and Mass Balance Implications. Reviews of Geophysics. 53: 119-161. [web] [.pdf]
33. J. MacGregor, W. Colgan, M. Fahnestock, M. Morlighem, G. Catania, J. Paden and S. Gogineni. 2016. Holocene deceleration of the Greenland Ice Sheet. Science. 351: 590-593. [web] [.pdf]
32. H. Machguth, M. MacFerrin, D. van As, J. Box, C. Charalampidis, W. Colgan, R. Fausto, H. Meijer, E. Mosley-Thompson and R. van de Wal. 2016. Greenland meltwater storage in firn limited by near-surface ice formation. Nature Climate Change. 6: 390-393. [web] [.pdf]
31. K. Kjeldsen, N. Korsgaard, A. Bjørk, S. Khan, J. Box. S. Funder, N. Larsen, J. Bamber, W. Colgan, M. van den Broeke, M. Siggaard-Andersen, C. Nuth, A. Schomacker, C. Andersen, E. Willerslev and K. Kjaer. 2015. Spatial and temporal distribution of mass loss from the Greenland Ice Sheet since 1900. Nature. 528: 396-400. [web] [.pdf]
30. C. Charalampidis, D. van As, J. Box, M. van den Broeke, W. Colgan, S. Doyle., A. Hubbard, M. MacFerrin, H. Machguth and C. Smeets. 2015. Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland. The Cryosphere. 9: 2163-2181. [web] [.pdf]
29. W. Colgan, W. Abdalati, M. Citterio, B. Csatho, X. Fettweis, S. Luthcke, G. Moholdt, S. Simonsen and M. Stober. 2015. Hybrid glacier Inventory, Gravimetry and Altimetry (HIGA) mass balance product for Greenland and the Canadian Arctic. Remote Sensing of Environment. 168: 24-39. [web] [.pdf]
28. W. Colgan, A. Sommers, H. Rajaram, W. Abdalati and J. Frahm. 2015. Considering thermal-viscous collapse of the Greenland ice sheet. Earth's Future. 3: 1-16. [web] [.pdf]
27. W. Colgan, J. Box, M. Andersen, X. Fettweis, B. Csatho, R. Fausto, D. van As and J. Wahr. 2015. Greenland high-elevation mass balance: inference and implication of reference period (1961-90) imbalance. Annals of Glaciology. 56: 105-117. [web] [.pdf]
26. R. Fausto, D. van As, J. Antoft, J. Box, W. Colgan and the PROMICE team. 2015. Greenland ice sheet melt area from MODIS (2000-2014). Geological Survey of Denmark and Greenland Bulletin. 33: 57-60. [web] [.pdf]
25. W. Colgan, H. Thomsen and M. Citterio. 2015. Unique applied glaciology challenges of proglacial mining. Geological Survey of Denmark and Greenland Bulletin. 33: 61-64. [web] [.pdf]
24. M. Citterio, D. van As, A. Ahlstrøm, M. Andersen, S. Andersen, J. Box, C. Charalampidis, W. Colgan, R. Fausto, S. Nielsen and M. Veicherts. 2015. Automatic weather stations for basic and applied glaciological research. Geological Survey of Denmark and Greenland Bulletin. 33: 69-72. [web] [.pdf]
23. M. Andersen, L. Stenseng, H. Skourup, W. Colgan, S. Khan, S. Kristensen, S. Andersen, J. Box, A. Ahlstrøm, X, Fettweis and R. Forsberg. 2015. Basin-scale partitioning of Greenland ice sheet mass balance components (2007–2011). Earth and Planetary Science Letters. 409: 89-95. [web] [.pdf]
22. W. Colgan. 2014. Considering the ice excavation required to establish and maintain an open ice pit. Journal of Cold Regions Engineering. 28: 04014003. [web] [.pdf]
21. D. Van As, R. Fausto, K. Steffen and The PROMICE Team. 2014. Katabatic winds and piteraq storms: observations from the Greenland ice sheet. Geological Survey of Denmark and Greenland Bulletin. 31: 83-86. [web] [.pdf]
20. M. Andersen, S. Andersen, L. Stenseng, H. Skourup, W. Colgan, S. Kristensen, J. Merryman-Boncori, A. Ahlstrøm, X. Fettweis, R. Forsberg, M. Citterio, J. Box, D. van As and R. Fausto. 2014. Mass loss from an ice-sheet drainage basin in West Greenland. Geological Survey of Denmark and Greenland Bulletin. 31: 87-90. [web] [.pdf]
19. W. Colgan, J. Box, R. Fausto, D. van As, V. Barletta and R. Forsberg. 2014. Surface albedo as a proxy for the mass balance of Greenland's terrestrial ice. Geological Survey of Denmark and Greenland Bulletin. 31: 91-94. [web] [.pdf]
18. W. Colgan, S. Luthcke, W. Abdalati and M. Citterio. 2013. Constraining GRACE-derived cryosphere-attributed signal to irregularly shaped ice-covered areas. The Cryosphere. 7: 1901-1914. [web] [.pdf]
17. W. Colgan and L. Arenson. 2013. Open pit glacier ice excavation: A brief review. Journal of Cold Regions Engineering. 27: 223-243. [web] [.pdf]
16. J. Box and W. Colgan. 2013. Greenland ice sheet mass balance reconstruction. Part III: Marine ice loss and total mass balance (1840-2010). Journal of Climate. 26: 6990-7002. [web] [.pdf]
15. T. Phillips, H. Rajaram, W. Colgan, K. Steffen and W. Abdalati. 2013. Evaluation of cryo-hydrologic warming as an explanation for increased ice velocities in the wet snow zone, Sermeq Avannarleq, West Greenland. Journal of Geophysical Research. 118: 1241–1256. [web] [.pdf]
14. D. Van As, R. Fausto, W. Colgan, J. Box and The PROMICE Team. 2013. Darkening of the Greenland ice sheet due to the melt-albedo feedback observed at PROMICE weather stations. Geological Survey of Denmark and Greenland Bulletin. 28: 69-72. [web] [.pdf]
13. D. McGrath, W. Colgan, N. Bayou, A. Muto and K. Steffen. 2013. Recent warming at Summit, Greenland: Global Context and Implications. Geophysical Research Letters. 40: 2091-2096. [web] [.pdf]
12. T. Zhang, C. Xiao, W. Colgan, X. Qin, W. Du, X. Liu, W. Sun, Y. Liu and M. Ding. 2013. Observed and modelled ice temperature and velocity along the main flowline of the East Rongbuk Glacier, Mt. Qomolangma (Everest). Journal of Glaciology. 59: 438-448. [web] [.pdf]
11. W. Colgan, W. Pfeffer, H. Rajaram, W. Abdalati and J. Balog. 2012. Monte Carlo ice flow modeling projects a new stable configuration for Columbia Glacier, Alaska, c. 2020. The Cryosphere. 6: 1395-1409. [web] [.pdf]
10. R. Anderson, M. Dühnforth, W. Colgan and L. Anderson. 2012. Far-flung moraines: Exploring the feedback of glacial erosion on the evolution of glacier length. Geomorphology. 179: 269-285. [web] [.pdf]
9. Y. Liang, W. Colgan, Q. Lv, K. Steffen, W. Abdalati, J. Stroeve, D. Gallaher and N. Bayou. 2012. A decadal investigation of supraglacial lakes in West Greenland using a fully automatic detection and tracking algorithm. Remote Sensing of Environment. 123: 127-138. [web] [.pdf]
8. W. Colgan, H. Rajaram, R. S. Anderson, K. Steffen, H. Zwally, T. Phillips and W. Abdalati. 2012. The annual glaciohydrology cycle in the ablation zone of the Greenland Ice Sheet: Part 2. Observed and modeled ice flow. Journal of Glaciology. 58: 51-64. [web] [.pdf]
7. W. Colgan, K. Steffen, W. S. McLamb, W. Abdalati, H. Rajaram, R. Motyka, T. Phillips, and R. Anderson. 2011. An increase in crevasse extent, West Greenland: Hydrologic implications. Geophysical Research Letters. 38. L18502. [web] [.pdf]
6. D. McGrath, W. Colgan, K. Steffen, P. Lauffenburger and J. Balog. 2011. Assessing the summer water budget of a moulin basin in the Sermeq Avannarleq ablation region, Greenland Ice Sheet. Journal of Glaciology. 57: 954-964. [web] [.pdf]
5. W. Colgan, H. Rajaram, R. Anderson, K. Steffen, T. Phillips, I. Joughin, H. Zwally and W. Abdalati. 2011. The annual glaciohydrology cycle in the ablation zone of the Greenland Ice Sheet: Part 1. hydrology model. Journal of Glaciology. 57: 697-709. [web] [.pdf]
4. T. Phillips, S. Leyk, H. Rajaram, W. Colgan, W. Abdalati, D. McGrath and K. Steffen. 2011. Modeling moulin distribution on Sermeq Avannarleq glacier using ASTER and WorldView imagery and fuzzy set theory. Remote Sensing of Environment. 115: 2292-2301. [web] [.pdf]
3. B. Balsley, L. Kantha and W. Colgan. 2010. On the use of Slow Ascent Meter-scale Sampling (SAMS) radiosondes for observing overturning events in the free atmosphere. Journal of Atmospheric and Oceanic Technology. 27: 766-775. [web] [.pdf]
2. W. Colgan, J. Davis and M. Sharp. 2008. Is the high-elevation region of Devon Ice Cap thickening? Journal of Glaciology. 54: 428-436. [web] [.pdf]
1. W. Colgan and M. Sharp. 2008. Combined oceanic and atmospheric influences on net accumulation on the Devon Island Ice Cap, Nunavut, Canada. Journal of Glaciology. 54: 28-40. [web] [.pdf]
W. Colgan. 2011. Modeling the influence of surface meltwater on the ice dynamics of the Greenland Ice Sheet. Ph.D. Thesis. University of Colorado. [.pdf]
W. Colgan. 2007. Reconstructing the recent accumulation history and mass balance trends for high elevation regions of the Devon Island Ice Cap in the Canadian Arctic. M.Sc. Thesis. University of Alberta. [.pdf]