Understanding the physical controls of ice melt by turbulent water flow under pressure is an essential problem in glaciology. Such melt is one of the main drivers of water flow through and under glaciers and a dominant contributor of ice loss at the boundary between glaciers and oceans. However, there exist no data to properly quantify this mechanism. We build a physical experiment where water flow under pressure in contact with a 3-meter-long block of ice. Twitter has the most up-to-date developments and some videos, and details about the experiment can be found here.
You can also explore the experiment set-up in 3D here.
Seismic noise caused by subglacial flows
Environmental seismology is a powerful tool to quantify flows on Earth. This method can be applied to subglacial water flow and sediment transport. In combining numerical modeling and data of subglacial seismic noise I can test either model, hopefully helping to better design future seismometer deployment.
To learn more, here is my presentation from the IGS Symposium on erosion and sedimentation in Madison, Wisconsin.
Using remote sensing of glacier surges in the Himalaya to better constrain glacier slip
Glacier surging is an enigmatic dynamic instabilities undergone only by ~1% of present-day glaciers worldwide. Glaciologist describe glacier surges as dynamic flow instabilities lasting from months to years, whereby the glacier motion increases by at least an order of magnitude. Surges tend to be cyclic, and thus represent and interesting natural experiment to understand triggers and terminations of fast glacier flow.
With J.P. Avouac’s group at Caltech and Surendra Adhikari at JPL, we are using a powerful image correlation technique (COSI-corr) that allows to extract ice surface velocities at short time-intervals and sub-pixel accuracy from Landsat and Sentinel optical satellite imagery. We are using the velocity timeseries to document and study the ongoing surge of Shishper glacier in Pakistan. (Animation showing 3 years of the velocity data)
In addition to the detailed satellite observation of the surge, we derived a generalized relationship to capture the glacier sliding, that is valid for any type of bed substrate. We then combine this new theoretical developments with the data from the surge to validate the theory and show that it is possible to quantify the sliding relationship parameters. (Accepted pre-print)
Poster presented at the 2020 AGU General Meeting.
What do we really know about glacial erosion?
Understanding glacial erosion is fundamental to our understanding of Earth surface evolution through time but its underlying mechanisms remain poorly constrained. These mechanism are relevant at orogenic timescales, to understand the formation of mountain ranges and relief, at the time scale of glacial cycles to understand the formation of landforms and for the present day to understand the future of sediment production and transport in glacial watersheds. In an effort to combine the research on glacial erosion pursued in different fields (glacial geomorphology, thermochronology, landscape evolution modelling and glaciology) and to put it in its historical context, I am working on a review of glacial erosion. For more details, the historic evolution of glacial erosion in the scientific literature is layout in the introduction of my PhD thesis.
Poster at the SoCal Geomorphology 2018 Meeting
Environmental Sciences and Engineering Seminar at Caltech (Jan. 2019)