Research

I have the unique opportunity to do both large-scale modeling and laboratory work for my graduate research.

Modeling

I am currently use the GEOS-Chem global atmospheric chemistry model to understand and quantify the sensitivity of the oxygen isotopes of sulfate to changes in atmospheric oxidant concentration. The goal is to produce modern, preindustrial, and glacial simulations that allow us to see how the oxygen isotopes of sulfate have changed with time in order to make more quantitative statements about ice core isotope records and thus the past oxidative capacity of the atmosphere.

The ICECAP (ICE age Chemistry And Proxies) project is a collaborate effort involving Becky Alexander and me at UW, Loretta Mickley and Lee Murray at Harvard, and Jed Kaplan at EPFL, and involves the construction of a modeling framework with which to model the climate chemistry and oxygen isotopes of sulfate back to the Last Glacial Maximum.

I recently presented a poster on changes in oxygen isotopes and oxidants between the present, preindustrial Holocene, and (very preliminary results of) Last Glacial Maximum at the AGU Fall Meeting 2009. [POSTER (2.4 MB file)]

Laboratory

We make measurements of the oxygen isotopes of sulfate and nitrate (Δ17O) in the UW Isolab. Recently, my lab work has focused on method development to reduce the sample size requirements by an order of magnitude. We are getting close to the point at which we can begin making measurements with this improved method.

In the summer of 2008, I spent a week working at the National Ice Core Lab (NICL), helping to process ~500 m of ice from the WAIS-Divide deep ice core. The photo of me on the homepage is from the core archiving room at NICL.

Undergraduate

Here is my undergraduate honors project on modeling the diffusion of gases through firn, including gas age distributions for WAIS-Divide, Antarctica and Summit, Greenland and an attempt to understand the O2/CO2 relationship in the South Pole firn.

The gas age distribution is required to calculate Δage — the gas-age–ice-age difference — which is important for getting ice and gas records from an ice core onto the same age scale. My WAIS-Divide age distribution is used in Mischler et. al., 2009.