Glaciers and ice sheets play key roles in the long story of Earth’s climate and landscapes.

Today, changes in the cryosphere also impact society on local and global scales. These changes ultimately depend on how climate variations are filtered through ice dynamics. My research focuses on these interactions. I use computational models, theoretical models, and data analysis to investigate how glaciers and ice sheets respond to climate forcing and other environmental changes. My goal is to improve how we account for ice dynamics and climate variability when interpreting observed glacier changes, or when calibrating models for projections into the future.

Check out some specific research areas below:

DSC_0496.jpeg

Ice sheets and outlet glaciers

The massive glaciers draining the Greenland and Antarctic Ice sheets are sensitive to both atmospheric and oceanic changes, with dynamics operating on many timescales. Ice flow is also highly sensitive to geometry and properties of the subglacial landscape. Much of my research attempts to untangle these climatic, topographic, and dynamical factors using model experiments.

For example:

  • How do fast and slow ice dynamics compare for changes driven by the ocean vs. the atmosphere? (paper)

  • How can we quantify anthropogenic effects vs. natural variability in driving rapid glacier retreats? (paper)

  • Under what conditions does sediment deposition help stabilize ice streams? (preprint here)

IMG_1258.jpg

Mountain glacier dynamics

Mountain glaciers are simpler than marine-terminating outlet glaciers, but there are thousands of them, spanning a huge range of geometries and climate settings around the world. So, it’s important to understand how core principles translate from one setting to another. For example, glaciers have a response time that depends on their geometry and local climate, meaning that they are in varying stages of adjustment to current warming.

I have investigated these time-dependent responses both in theoretical terms (paper here), and for glaciers in the Washington cascades (paper here).

Currently, I am investigating what this means for changes in the contribution of glacier melt to streamflow.

Screen Shot 2021-02-02 at 10.28.37 PM.png

Climate variability and glacier mass balance

Glaciers depend on a balance between snowfall and melt (whether on the surface or at the ocean). Natural climate variability makes this balance noisy on short timescales, creating statistical challenges both for observations and models. I’m interested in this upstream climate variability that affects glaciers and ice sheets, and how to characterize it in space and time.

In the past I’ve analyzed atmospheric variability that affects mountain glaciers (paper), and more recently on the atmosphere-ocean variability relevant to Greenland’s outlet glaciers.

Screen+Shot+2021-02-02+at+11.28.07+PM.jpg

Radioglaciology

Above: Snow-depth measurements on South Cascade Glacier, WA

Radar is a powerful tool for observing the structure and evolution of glaciers and ice sheets. While I am mostly a modeler, I’ve joined several field projects, from the North Cascades to Antarctica, using radar to measure snow accumulation, subglacial topography, and internal ice layers. I am always interested in learning from such observations, which may directly constrain models, or reveal new features of the natural systems we seek to understand.