Research


My research focuses on climate dynamics and variability across the atmosphere, ocean, and cryosphere. I use a combination of theory, numerical modeling, climate model analysis, and simple dynamical models to understand how ice sheets, sea ice, and large-scale modes such as ENSO and the QBO interact with eachother and the broader climate system.

A common thread in my work is the use of model hierarchies: pairing complex climate model output with idealized and conceptual models to isolate mechanisms, test hypotheses, and distinguish signal from noise in a highly variable climate system.


1. Paleoclimate Modeling: understanding glacial cycles

One line of my research examines the growth and retreat of icesheets (in particular the Laurentide Ice Sheet (LIS)) across the glacial cycles.

Glacier mass balance schematic
Glacier mass balance and atmospheric circulation. By NASA. From Wikimedia Commons.
  • Generally, I examine how the surface mass balance (SMB) of various ice sheets responds to changes in albedo, temperature, precipitation, and sea ice cover.
  • I compute the SMB of the LIS using the isotope-enabled iTRACE simulation and compare it with mass-loss rates inferred from geophysical reconstructions (e.g., ICE-6G).
  • Ongoing work investigates why the LIS grew near 80 ka but retreated rapidly near 12 ka, disentangling the relative roles of insolation, sea-ice extent, circulation changes, and feedbacks tied to albedo and meltwater.

Together, these projects aim to clarify the conditions under which ice-sheet evolution is primarily controlled by external forcing versus internal climate variability.


2. Pacific Teleconnections: ENSO–QBO interactions and large-scale variability

Another focus of my work is the interaction between ENSO (El Niño–Southern Oscillation) and the Quasi-Biennial Oscillation (QBO).

ENSO schematic
ENSO schematic. NOAA Climate.gov, based on original provided by Eric Guilyardi.
  • Using reanalysis and CMIP6 preindustrial control runs, I evaluate whether the observed ENSO–QBO correlation is evidence of a robust dynamical coupling or can be explained by statistical coincidence in a short record.
  • In companion work, I develop simple dynamical models to test candidate mechanisms, including QBO impacts on wave propagation, tropical upwelling, and ENSO amplitude and timing.
  • Separately, I advise an undergraduate research student working on machine learning techniques to classifying westerly wind bursts.

This combination of data analysis and theory aims to determine when we can confidently claim a mechanistic teleconnection versus when apparent relationships are consistent with stochastic variability.


3. Sea Ice, Surface Mass Balance, and High-Latitude Feedbacks

I am also interested in how sea-ice variability interacts with ice-sheet and ice-sheet–adjacent climates.

sea ice smb schematic
How seaice variability might affect SMB (of GrIS). Created by Kirstin Koepnick.
  • I study how changes in Arctic sea ice affect the surface mass balance of the Greenland and Laurentide Ice Sheets, focusing on the competing roles of insulating sea ice, open-ocean heat fluxes, and atmospheric circulation.
  • Using idealized experiments and simple energy-balance and diffusion models, I investigate how sea-ice–driven anomalies in surface fluxes and temperature propagate into the snow and firn and influence melt and refreezing.

These projects connect high-latitude processes to longer-term evolution of ice sheets and help clarify the physical pathways through which sea ice can modulate SMB.


Methods and Model Hierarchies

Across these projects, I use:

  • Climate model simulations: for my paleoclimate research, I run CESM2 with CAM5 physics adjusting topography and bathymetry for LGM and 12ka conditions
  • Climate model analysis: CESM2, iTraCE, CMIP6 control runs
  • Simple and intermediate-complexity models: conceptual climate and ice-sheet models, stochastic ENSO models
  • Numerical modeling: diffusion and energy-balance models for subsurface temperature and SMB
  • Statistical tools: bootstrapping, surrogate time series, and machine-learning-based classification of westerly wind bursts

By moving up and down a hierarchy of models and data sources, I aim to bridge mechanistic understanding with realistic climate behavior.