A paper I wrote with Roger Samelson and Dudley Chelton on the propagation of quasigeostrophic eddies was published in final (or near final) form today. You can download the preprint, or, even better, checkout some of the supplemental material.

This feel like good science to me because the paper clearly states a hypothesis and then sets out to disprove it. In this case we tested the hypothesis that linear Rossby wave theory can explain the sea-surface height observations (check out the movie). A number of metrics are used to show that the linear theory is inadequate.  We then go on to show that nonlinear quasigeostrophic theory does actually explain most of the observed sea-surface features.

The second part of the paper considers the dynamics of individual eddies in the nonlinear quasigeostrophic equation, including propagation speed, vorticity dynamics, and fluid trapping properties. There’s some great stuff here and you should definitely watch the movies of the tracer transport.

One cool part of this study was the intersection of theory and observations. While I was looking at my model output from the data, Dudley was also looking at observation data. Together with Roger, the three of us devised various ways of testing the model output to disprove the hypothesis resulting in most of what you see in the first part of the paper. I learned a lot from doing this.

One neat anecdote: in one case a theoretical prediction was found first, and then compared with observations. Specifically, after we found the relationship between propagation speed and amplitude of individual eddies, I remember Dudley running back up stairs and checking the observational data to see if the same trend existed. Some time later (a day? a month?) he found a way to show that, indeed, such a pattern did exist (even if the exact trend couldn’t be confirmed).

Anyway, this was a fun study.