My work focuses on understanding the coupled interaction of the Arctic atmosphere, sea ice, and ocean. I use drifting buoys, satellites, and computer simulations to better understand how this system works, how it has changed over time, and how it may behave in the future as the Arctic warms in response to anthropogenic climate change.

The Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC)

I participated in the international Arctic drift expedition MOSAiC during the setup phase in fall 2019. You can read about my experience here. During the expedition, we worked together to simultaneously measure as many components of the Arctic system as possible, from deep ocean currents to snow crystals and up into the clouds. My role was to deploy GPS-enabled buoys in an array surrounding the ship R/V Polarstern in order to track sea ice motion. The collection of buoys and other autonomous sensors surrounding the main site was called the MOSAiC Distributed Network (paper here).

The MOSAiC data was produced and quality-controlled using public funds from a long list of countries, which means that anyone who wants to can take a look at the data and use it for science. The buoy drift tracks, for example, are now publicly available from the Arctic Data Center, and the paper describing the buoy dataset can be read here.

Sea ice dynamics in the Fram Strait, as the ice pack broke apart

Recently, my colleagues and I published a paper documenting how the motion of the sea ice responds to transitions in ocean currents as the ice is carried through the Fram Strait into the “sea ice graveyard.” The Fram Strait is the passage between Greenland and the Svalbard island archipelago. Our data showed that the balances of wind, ice, and ocean changed as the buoys drifted over undersea features. We were able to detect the influence of tidal currents on the sea ice motion. The results highlight the importance of accounting for both wind and ocean currents when analyzing sea ice motion in the marginal ice zone. You can read more in the university press release.

How the structure of a cyclone changes the air-ice-ocean interaction

Our next focus was to examine extreme events from the set of MOSAiC observations. I zoomed in on an odd spike in the drift speed, a 12-hour period in February 2020 where the sea ice suddenly accelerated to its fasted speed of the whole winter period. As it turned out, a strong Arctic cyclone had passed directly over the ice camp on that day. Working with colleagues from universities across the country and across the Atlantic, we delved into the structure and impacts of the storm. We combined data from weather balloons, weather forecast models, atmospheric and sea ice radars, ocean flux buoys, meteorological towers, and from our network of drifting buoys, allowing us to document the structure of the storm, and watch the transfer of energy from the atmosphere, through the ice, into the upper ocean. You can read the ensuing paper in the Journal of Geophysical Research-Atmospheres. The work was selected for an Editor’s Highlight, an indicator of the novelty and importance of the study.

Tracking sea ice floes from space

Measuring sea ice motion in the Arctic is hard and expensive ^{[citation needed]}. While people have lived on Arctic coasts since time immemorial, the central Arctic Ocean is an inhospitable place. Despite frequent expeditions, it is still impossible for people to directly measure ice motion throughout the central Arctic simultaneously. To get around that issue, we use satellite imagery. Satellite measurements of sea ice concentration and extent form one of our longest climate records, documenting decreasing sea ice extent over the last 40 years.

With my colleagues at the Wilhelmus Lab in the Brown University Center for Fluid Mechanics, I’m researching a new method for tracking the motion of ice at (relatively) small scales. The Ice Floe Tracker algorithm identifies the boundaries of sea ice floes in satellite photographs, then uses a shape-matching procedure to link identified floes in subsequent images. Along the way, the algorithm tracks the rotation of the floe, enabling indirect measurement of ocean eddy kinetic energy.

Temperature inversions in the Arctic atmosphere

Typically, air gets colder the higher you go. That’s why you get snow on top of mountains. But in some conditions, you can get cold air underneath a layer of warm air. That’s called a temperature inversion. My PhD research focused on the structure of the lower troposphere (the region from the surface to 5 km altitude) in the Arctic. I carried out a climatological investigation of temperature inversions from 20 years of weather balloon observations, showing seasonal and spatial variation in the frequency, position, and strength of temperature inversion layers. In addition, I used results from two large ensemble climate model experiments to examine the causes of differences in atmospheric stability trends across the Arctic.