Ongoing Research Projects

Work in our group generally follows several directions, which can be disparate at times but are all aimed at a single goal:
Understanding how climate variability affects the risks associated with extreme weather events around the world.
The major research themes ongoing in the group are described below; for specifics, also check out the ‘Publications’ tab.

El Nino/Southern Oscillation Dynamics

The El Nino/Southern Oscillation, or ENSO, is the dominant driver of year-to-year climate variability around the world. Although the basic mechanisms (quasi-periodic changes to the tropical Pacific trade winds) are becoming better understood, it is still not clear exactly how external (natural and anthropogenic) influences affect the properties of El Nino and La Nina events. We use large ensembles - sets of many climate model simulations with slightly different starting points - to try and understand the reasons why future projections disagree.

Climate Change and Drought

Drought conditions in arid regions like the southwestern US can be extreme at times. Even without climate change, there was already the possibility for droughts lasting multiple decades to occur naturally - and these so-called “megadroughts” are expected to become even worse in the future. We use future projections with climate models to understand the magnitude of these trends and their corresponding impacts.

Improving Paleoclimate Reconstructions

In order to understand how tropical Pacific variability may respond to climate change, we need to build up good statistics of how it has varied in the past. But the El Nino/Southern Oscillation changes over long timescales, meaning that our observational records are far too short. Coral reconstructions are one of the best sources of information on past ENSO variability, but our ability to use them quantitatively is limited by our lack of detailed physical understanding of how El Nino and La Nina events lead to changes in temperature and seawater isotopic composition in reef environments. We use field observations, regional ocean models, and large-scale observational products to find ways to improve reconstruction accuracy from coral records.

 Climate Variability and Marine Ecosystems

Many marine ecosystems are vulnerable to changes in their local physical conditions, through effects from ocean acidification, deoxygenation, or increases in temperature. Many of these are expected to in turn be affected by long-term trends in climate - but we still don’t have a good idea how climate variability (changes from year to year) may affect ‘shocks’ to those ecosystems. We combine observational datasets with regional ocean models and climate model simulations to try to improve our understanding of these influences.