Robert Hawley Glaciology and Remote Sensing

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Overview:

Bob Hawley started working as a glaciologist in 1995, as an undergraduate at the University of Washington, through the National Science Foundation 'Research Experience for Undergraduates' (REU) Programme. Following the completion of his BS degree he continued in glaciological research by participating in the inaugural winter-over at Summit camp, Greenland, during the 1997-1998 boreal winter. He earned a Ph. D. in geophysics from the University of Washington in 2005. His research interests include: the physics of firn densification, mass balance of large ice sheets, interpretation of ice core records, and remote sensing. He has worked primarily in East and West Antarctica and Greenland.

Bob's research has primarily focussed on the firn layer of polar ice sheets, frequently at the locations of deep ice cores. His investigations into techniques for measuring in-situ densification profiles of polar firn led to the development of a new technique called Borehole Optical Stratigraphy, in which a video camera is lowered down a borehole in the ice, and a recording is made of the patterns of light and dark in the borehole walls. These patterns of light and dark are associated with variations in ice grain size and density, and thus can be related to the annual layers commonly used to date ice cores in high-accumulation locations. Additionally, these layers can be used as natural markers, and their movements tracked through time as the firn column compresses. This provides a continuous profile of the vertical motion of the firn, which can allow the calculation of an independent depth-age scale. The firn is also of major importance to radar altimetry studies like the current ESA mission CryoSat. Fluctuations of firn density might affect the height of the surface measured by the radar altimeter, and penetration of the radar wave into the firn can also have other interpretable results. Bob is currently working with ESA data to define new ways to use the interferometric information from the SIRAL radar altimeter, the primary payload of CryoSat.

Information about specific research interests and current projects

Research Group Website:

Personal Website:

Selected Recent Publications:

Hawley, R.L ., E.M. Morris. 2006. Borehole Optical Stratigraphy and neutron-scattering density measurements at Summit, Greenland . Journal of Glaciology. 52(179), 491-496.

Bay, R. C., N. Bramall, P. B. Price, G. D. Clow, R. L. Hawley, R. Udisti, E. Castellano. 2006 .Globally-synchronous ice core volcanic tracers and abrupt cooling during the Last Glacial Period. Journal of Geophysical Research 111(D11108).

Hawley, R.L ., E.M. Morris, R. Cullen, U. Nixdorf, A.P. Shepherd, and D. Wingham. 2005. ASIRAS airborne radar resolves internal annual layers in the dry-snow zone of Greenland. Geophysical Research Letters33(L04502), doi:10.1029/2005GL025147.

Hawley, R.L ., E.D. Waddington, G.L. Lamorey, and K.C. Taylor. 2004. Vertical-strain measurements in firn at Siple Dome, Antarctica. Journal of Glaciology. 50(170). 447 - 452.

Hawley, R.L ., E.D. Waddington, R.B. Alley, and K.C. Taylor. 2003. Annual layers in polar firn detected by Borehole Optical Stratigraphy. Geophysical Research Letters30(15), doi:10.1029/2003GL017675.

Hawley, R.L ., E.D. Waddington, D.L. Morse, N.W. Dunbar, and G.A. Zielinski. 2002. Dating firn cores by vertical strain measurements. Journal of Glaciology, 48(162), 401 - 406.

Albert, M.R. and R.L. Hawley. 2002. Seasonal changes in surface roughness characteristics at Summit, Greenland: implications for snow and firn ventilation. Annals of Glaciology 35, 510-514.

Albert, M.R. and R.L. Hawley. 2000. Seasonal differences in surface energy exchange and accumulation at Summit, Greenland. Annals of Glaciology31, 387-390.