Glaciology student wins college-wide award

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Congratulations to Margot Vore for winning the “Outstanding Research Poster” award at the annual UIdaho College of Science student research fair!  Margot’s presentation was obviously very well received by all who stopped at her poster during the October 27 event.

Enthusiasts of glaciohydraulic tremor who missed the research fair can catch the latest at Margot’s oral presentation in the cryoseismology session at AGU this December, in New Orleans.  Bravo!

Margot receives her award from College of Science Dean Ginger Carney
Margot receives her award from College of Science Dean Ginger Carney

Research group presents at Northwest Glaciologists in Vancouver, BC

The UI Glacier Dynamics Group traveled to the annual meeting of Northwest Glaciologists in mid-October to present their latest research and share ideas with other regional glaciologists.  Univ. of Idaho grad students Margot Vore and Tristan Amaral made excellent presentations of their latest work.  Colleagues at the University of British Columbia and Simon Fraser University were wonderful hosts, and Vancouver, BC, treated us to glorious weather.  We’re looking forward to future years of this favorite gathering of the minds.

Margot Vore presents her research on the seismic signals produced by subglacial water flow.
Margot Vore presents her research on the seismic signals produced by subglacial water flow.

U Idaho group presents and participates in international workshops

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It’s been a busy summer for the Glacier Dynamics group, with a number of high-profile presentations focused around glacier seismology.

In June, Tim participated in back to back workshops on Environmental Seismology, then taught during a weeklong summer course on Glacier Seismology.  During the Environmental Seismology workshop, Tim gave one of the evening keynote lectures, during which he presented an overview of his and others efforts to use seismology to better understand glaciological processes.  The workshop took place in Bavaria, Germany, and was attended by approximately 60 international scientists, many of which took part in the excellent field trip to a rockfall monitoring site in the alps.

Following the meeting in Germany, Tim flew straight to Fort Collins, CO, for the Glacier Seismology course to present on glacier hydrology, iceberg calving, and the seismic signals produced through these mechanisms.  Margot, a member of our lab, participated as a sponsored student in the Glacier Seismology course, and presented her research to date on Taku Glacier during the course.

 

A slide from the wrap-up to the Environmental Seismology workshop playfully illustrates the mechanism by which falling icebergs produce calving icequakes [Bartholomaus et al., 2012]
Environmental seismologists return from their field trip in the alps.

Understanding subglacial hydrology through seismology

Last week, I visited the Boise State Geosciences department to give a seminar on the use of seismology to understand subglacial water flow and sediment transport.  I reviewed two of my recent papers, published in GRL (this in 2015, and this in 2016), and also presented some of the initial results from my work with graduate student, Margot Vore, from Taku Glacier.  I enjoyed getting to know some other Idaho geophysicists and identifying new opportunities for collaboration.

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Glacier Dynamics at the University of Idaho

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.

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Seismology for glaciology

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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.

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Press write-up of AGU presentation

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.

 

 

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A seismometer deployed at the terminus of a west Greenland glacier for two years, between 2013 and 2015. This station recorded over a million icequakes, year-round.

Plenary talk at the Earthscope National Meeting

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Tim will be attending the 2015 Earthscope National Meeting in Stowe, VT, to deliver a plenary talk on the use of seismology and GPS to learn about glacier dynamics.  This talk, on June 15th, will cover some of the projects Tim has been involved with in Alaska to understand subglacial hydrology, fast glacier flow, and iceberg calving, as well as future opportunities in Alaska and Greenland.

The meeting, from June 15-17, will broadly be discussing Earth’s deformation in North America and beyond, and the future of the Earthscope project.

Time series of calving icequakes can be used to track variations in iceberg calving rate, for example, how calving responds to rising and falling diurnal ocean tides.
Time series of calving icequakes can be used to track variations in iceberg calving rate, for example, how calving responds to rising and falling diurnal ocean tides.

The extended abstract for my presentation is below.

Understanding the Processes Driving Glacier Change with Alaskan Seismic and GPS Data

Timothy C. Bartholomaus, Christopher F. Larsen, Michael E. West, Shad O’Neel, Ginny Catania

Worldwide, glaciers and ice sheets are losing mass and increasing global sea level (Shepherd and others, 2012; Gardner and others, 2013). However, the processes controlling these changes are not well understood. Changes in glacier hydrology and iceberg calving can both increase rates of glacier flow, thereby hastening delivering of ice to the ocean and low elevation regions. The understanding of these two processes is not yet sufficient to reliably include them in ice flow models for the prediction of sea level rise.

The application of seismology and GPS techniques within glaciology allows insight into glacier hydrology and iceberg calving processes. At Yahtse Glacier, a tidewater glacier in Alaska, we seismically quantified calving at unprecedented tidal to seasonal timescales. Tracking of calving-generated icequakes reveals that calving of large icebergs is significantly more likely to occur during falling and low tides than during rising and high tides. We also observe that calving fluxes are greater during the late summer and fall than during winter, suggesting that, on the coast of Alaska, submarine melt of glacier termini is likely a dominant control on the calving rate (Bartholomaus and others, 2013). Background seismic noise (i.e., tremor) also offers glaciological insight. Tremor amplitude rises and falls seasonally and after storms, synchronously with subglacial discharge. Thus, subglacial discharge variations can be quantified at tidewater locations where discharge has been previously unknown.

At Yahtse Glacier and Kennicott Glacier, also in Alaska, we use GPS to observe contrasting responses in glacier motion to melt, rain, and lake-drainage events (Bartholomaus and others, 2008). At Kennicott, speedup responses are short-lived and glacier motion quickly returns to background levels. Yahtse Glacier’s response to hydrologic events is long-lived and leads to progressively slower flow over the course of the summer, demonstrating that in some cases changes in subglacial water routing are not reversible on daily to weekly timescales.

Together, seismic and GPS data offer views of glacier responses to environmental change with temporal resolution that is not available through approximately weekly satellite images. These highly resolved observations allow physical insight that improves our understanding of glacier physics, eventually allowing for better inclusion of glacier dynamical processes in ice flow models. Going forward, Earthscope’s Transportable Array in Alaska expands on the present opportunity to remotely track iceberg calving across coastal Alaska.­ New terrestrial radar interferometers offer a more complete view of ice flow variability by combining the spatial resolution of satellite imagery with the temporal resolution of GPS.

 

Presentations and sessions at AGU

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This year, I’ll be giving an invited talk in one of the ice/ocean interaction sessions, and convening another session focused on iceberg calving and submarine melt at the termini of tidewater glaciers. My talk, at 11:20 on Wednesday in MW 3007, will describe how we can use seismic noise to observe subglacial discharge at tidewater glaciers (C32B-05). My convened session is co-chaired with Ellyn Enderlin and covers a wide range of oceanographic and glaciological observations and models.  For this session:

  • The talks will be on Thursday at 4pm in MW 3007 (C44B).
  • Posters are on Tuesday afternoon in MW (C23A).  The posters for two other similar sessions are at the same time, so I’m expecting that we’ll have a lively, well-attended poster session.

This is also the first year for which I have scheduled the glaciology program on behalf of the AGU Cryosphere focus group.  The planning for this meeting took place over the spring, summer and fall of this last year. I’m wishing everyone a great meeting, and that conflicts in the schedules of glaciologist conference attendees are kept to a minimum!

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