My research and that of my students is focused on improving our understanding of large-scale climate variability. The preponderance of my work is based on the analysis and diagnosis of observational data. But it has also exploited simple balance models, idealized general circulation models and the output from coupled chemistry-climate and atmosphere-ocean general circulation models.
In general, my papers are focused on 1) identifying novel aspects of the climate system in observations and 2) testing hypotheses motivated by observational analyses in numerical models. My papers have explored atmospheric variability across a range of spatial and temporal scales, including the origins and impacts of large-scale patterns of climate variability, the mechanisms that underlie observed climate change and the simulated response to external climate forcing, the signatures of and mechanisms for stratosphere/troposphere coupling, ocean/atmosphere interaction in the Southern Hemisphere and North Atlantic, decadal climate variability, and the role of cloud radiative effects in climate variability.
My current research is focused on the following topics:
Exploring the influence of cloud and clear-sky radiative processes on the large-scale atmospheric circulation, especially at middle and high latitudes. The work includes using observations and targeted numerical experiments to explore the role of radiative processes in governing the amplitude and structure of the climatological-mean extratropical circulation and its variability.
Exploring the structure and origins of periodicity in extratropical wave amplitudes (i.e., storminess) on ~20-25 day timescales. The research includes analyzing and diagnosing periodicity in the large-scale circulation in observations, developing idealized models of the periodicity, and exploring the implications of the periodicity for subseasonal variations in surface weather.
Developing dynamical and statistical methods for distinguishing between the signatures of internal variability and anthropogenic forcing in climate change. The work includes exploiting large-ensembles of climate change simulations to inform analyses of observed climate change.
Understanding the role of the ocean circulation in extratropical climate variability. The research includes probing 1) the importance of the ocean circulation in driving observed variability in the sea-surface temperature field using remotely-sensed data in conjunction with ocean state estimates, and 2) the resulting impacts of the ocean-circulation induced sea-surface temperature anomalies on the global-climate system in "pace-maker"-style numerical simulations.
Exploring the importance of coupled chemical/dynamical processes for climate variability in observations and coupled-chemistry climate models.
Please also see the Annular Modes website, which includes basic background material on annular variability: Annular Modes Website