I’m excited to welcome Margot Vore to my glacier dynamics group at UI. Margot will be working to better understand the flow of water through and under glaciers, through the analysis of seismic data. She’ll be analyzing seismic data recorded in 2016 near the terminus of Taku Glacier, outside of Juneau, in Southeast Alaska. Margot comes to UI from CU-Denver, where she completed her Bachelor of Science degree majoring in math, and minoring in environmental science. We’re happy to have her here in Moscow!
This fall, I’ve moved to the University of Idaho to begin work as an Assistant Professor and expand my lab group. I’ve begun working with a graduate student who will work with glaciohydraulic tremor data to better understand changes in subglacial hydrologic processes. Moscow, ID, home to the university, is a great town and I’m looking forward to getting to know the community and landscape while I establish my research here.
Please get in touch if you’re interested in joining my glacier dynamics group as a grad student or postdoc, or otherwise collaborating.
I’ll be giving a talk in the plenary session on Renaissance Seismology: Seismology for Non-Traditional Targets at the upcoming IRIS National Workshop, in Vancouver, WA. I’m looking forward to sharing my perspectives on the tremendous utility of seismology for glacier problems, and learning about the latest seismological research and techniques. I’m also happy about this being a short trip. It’s my first meeting out of my new home in Moscow, ID, where I’ll start as an Assistant Professor at the University of Idaho in the fall.
IRIS is the national coordinating body for seismological research in the US – it stands for Incorporated Research Institutions for Seismology.
Three new papers are now in press in Geophysical Research Letters, Journal of Glaciology and the Annals of Glaciology. These papers are:
Bartholomaus, T. C., L. A. Stearns, D. A. Sutherland, E. L. Shroyer, J. D. Nash, R. Walker, G. Catania, D. Felikson, D. Carroll, M. J. Fried, B. Noël, M. van den Broeke (in press), Contrasts in the response of adjacent fjords and glaciers to surface melt in western Greenland, Annals of Glaciology.
In which we integrate glaciological and oceanographic observations from the west coast of Greenland to demonstrate how subglacial hydrology has contrasting effects on the glacier and fjord dynamics within neighboring systems.
Gimbert, F., V. C. Tsai, J. M. Amundson, T. C. Bartholomaus, and J. I. Walter (in press), Sub-seasonal pressure, geometry and sediment transport changes observed in subglacial channels, Geophysical Research Letters.
In which we demonstrate how seismic and discharge measurements can be combined to identify how subglacial pressure gradients within Rothlisberger channels and channel size vary over the course of the melt season at a glacier in Alaska. Additionally, we discuss variations in sediment transport and the impact of flowing water on glacier motion.
Brinkerhoff, D., C. R. Meyer, E. Bueler, M. Truffer, and T. C. Bartholomaus (in press), Inversion of a glacier hydrology model, Annals of Glaciology, 57(72).
In which we constrain the evolution of the subglacial hydrologic system through measurements of glacier water discharge, glacier motion, and estimates of water inputs.
I’ve begun tweeting, under the handle @TimBartholomaus. I’m commenting about glaciology, sea level rise, climate science, polar and alpine field work, and science in general. You can follow my posts, with or without your own Twitter account, at https://twitter.com/TimBartholomaus
One of my two presentations at the AGU fall meeting this year is the subject of a well done blog post. In the presentation, my co-authors and I reported the detection of over one million icequakes produced near the terminus of a tidewater glacier in west Greenland. Study of these icequakes will allow us to better understand the factors controlling the flow of glacier ice, and ultimately allow scientists to make more precise predictions of sea level rise.
We’re presently about half way through the meeting this year and its been a good week so far. During the Saturday and Sunday prior to the beginning of the AGU fall meeting, I participated in a planning workshop to lay the groundwork for a monitoring network to observe ice-ocean interactions in Greenland. I made the case for the value of seismology in understanding tidewater glacier dynamics.
My second invited presentation is a poster on Thursday afternoon. I’ll be sharing observations and interpretations of high-rate velocity variations near the front of one of Greenland’s largest ocean-terminating glaciers. The presentation is C43B-0805 High-resolution, terrestrial radar velocity observations and model results reveal a strong bed at stable, tidewater Rink Isbræ, West Greenland.
I’m pleased to report that I’ve been promoted from Postdoctoral Fellow to Research Associate, at the University of Texas Institute for Geophysics in Austin, Texas. I’ll be continuing my research into glaciological processes and glacier change through the use of seismology, terrestrial radar interferometry, satellite and airborne imagery, and other geophysical tools. More papers and proposals, the currency of our trade, are on their way. I look forward to continuing and initiating collaborations, with students and fellow PIs, in the years to come.
After spending September in Greenland, the UT/KU team has returned from our third and final field season in the Uummannaq region of western Greenland. We recovered equipment that has been monitoring tidewater glaciers in the region for two years, as well as made a set of shorter-term, higher-resolution observations that required us to camp adjacent to one of the glaciers for 10 days. We’re looking forward to working with the data, and sharing our results at this fall’s AGU meeting, future conferences, and in publications.
The seismometers, GPS, timelapse cameras, and weather stations we recovered were in great shape. We also recorded excellent terrestrial interferometric radar observations (in spite of strong, consistent katabatic winds) and more seismic and GPS data. Due to the lateness of our field work (our previous field work has been in July and August), we also got to experience the transition in seasons, from fall to winter. This meant wonderful twilight, rich red tundra, and the first snows on the mountain tops.
You can read more about this interdisciplinary, NASA-funded project here.
A new study, published August 10 in Geophysical Research Letters, demonstrates how seismic tremor can be used to track variations in the flow of water emerging from the termini of marine-terminating glaciers. This tremor, sometimes referred to as “seismic noise,” is recorded on seismometers, common earthquake monitoring instruments. Measurements of subglacial discharge variation at tidewater glaciers, which thus far have not been achieved, are a critical step towards understanding the present and future behavior of some of the largest and most rapidly-changing glaciers on earth–those that end in the ocean. Not only does subglacial water control fast glacier flow, but subglacial water discharged into fjords promotes glacier melt below sea level and can erode and redeposit glacier-stabilizing sediment at glacier fronts. These newly-reported observations of glaciohydraulic tremor open a broad new avenue through which to study these important phenomena. The study was authored by Tim Bartholomaus, Jason Amundson, Jake Walter, Shad O’Neel, Mike West and Chris Larsen.
This study has been reported on the radio by the Austin, TX, NPR affiliate, and by EOS, the American Geophysical Union’s news publication. Additional coverage includes the Aug. 31 issue of the magazine Engineering News Record, as well as several websites, including, grist.org, futurity.org, phys.org, and Environmental Monitor.
You can read the UT press release about our study here.
Over the last month, I’ve had the pleasure of submitting three, new, first-author papers for peer review with a diverse set of co-authors. These papers are a combination of wrapping up old projects (including the last of my Ph.D.-related work) from Alaska, and also the first of new work coming out of Greenland. These manuscripts include unprecedented observations of tidewater glacier subglacial discharge through analysis of seismic tremor, characterization of the tremendous importance of subglacial discharge on the dynamics of adjacent tidewater glaciers and fjords in Greenland, and high-fidelity seismic monitoring of tidal and seasonal variations in iceberg calving. This is an exciting time, and I count myself lucky to be working with an excellent group of scientists. My teams and I are hoping for a few new C.V. line items later this year!
The papers in review are as follows:
Bartholomaus, T. C., J. M. Amundson, J. I. Walter, S. O’Neel, M. E. West, and C. F. Larsen, Subglacial discharge at tidewater glaciers revealed by seismic tremor, Under review at Geophysical Research Letters.
Bartholomaus, T. C., C. F. Larsen, M. E. West, S. O’Neel, E. C. Pettit, and M. Truffer, Tidal and seasonal variations in calving flux observed with passive seismology, Under review at Journal of Geophysical Research.
Bartholomaus, T.C., L. A. Stearns, D. A. Sutherland, E. L. Shroyer, J. D. Nash, R. Walker, G. Catania, D. Felikson, D. Carroll, M. J. Fried, B. Noël, M. van den Broeke, Contrasts in the response of adjacent fjords and glaciers to surface melt in western Greenland, Under review at Annals of Glaciology.