Princeton University

Much of the research in AOS feeds into models and theories of climate. Studies of future climate change provide an especially important unifying focus: research in Global Geochemical Cycles is needed to determine the future uptake of anthropogenic carbon by the oceans and land surfaces; research into Atmospheric Chemistry and Physics is central to understanding the complex cloud feedbacks and the interplay between aerosols, radiative transfer and clouds that help determine climate sensitivity; research on Ocean Dynamics and Circulation provides tools needed for studying the stability of the meridional overturning circulation in the Atlantic Ocean as well as for developing closure theories for unresolved oceanic processes in climate models; and research on Atmospheric Dynamics and Circulation generates theories and models for studying the impact of global warming on hurricanes, and the mechanisms responsible for the poleward shift of the jet streams as the climate warms. A similar crosscut through AOS research feeds into studies of paleoclimatology, with a particular emphasis on understanding the glacial-interglacial cycles of the Pleistocene. Studies of the remote past and the future build, in turn, on our understanding of and ability to simulate the present climate and that of the recent past: research projects may have as a goal improving our understanding of and ability to simulate the frequency of El Nino events, the location and orientation of the midlatitude storm tracks, or the extreme droughts in the African Sahel in the 1970's and 80's.

The left panel is the observed linear trend in observed rainfall (as estimated by the Climate Reasearch Unit of the University of East Anglia) in units of mm/month per 50 years.  Blue areas correspond to a trend towards wetter conditions and brown areas toward a drier climate.  The center panel is the same linear trend in the ensemble mean over 8 realizations of GFDL's latest global climate model (CM2), which is forced by estimates of the changing greenhouse gas composition of the atmosphere, as well as changing volcanic and anthropogenic aerosols, solar forcing, ozone concentrations, and land use.  The right panel is the same trend but for an ensemble mean of 10 simulations with AM2, the atmosphere/land component of CM2 running over observed sea surface temperatures (SSTs) and with fixed greenhouse gases and other forcings.  The implication of the right panel is that the drying trend in the Sahel is encoded in the distribution of SSTs and that the atmosphere/land model is capable of translating these SST changes into precipitation trends.  The implication of the center panel is that at least part of the signal in SSTs that generates this drought pattern is a consequence of changes in forcing.  See Held et. al., 2005:  Simulation of Sahel drought in the 20th and 21st centuries, Proc. Nat. Acad. Sci., 102(50), 17891-17896.

Faculty
Isaac Held
Gabriel Lau
Michael Oppenheimer
George Philander
Geoff Vallis

Students
Gang Chen
Nevin Fuckar
Sarah Kang
Ying Li
Ian Lloyd

Post-Docs
Ricardo Farnetti
Ken Takahashi
Ming Zhao

GFDL Researchers
Tom Delworth
Gabriel Vecchi
Andrew Wittenberg
Rong Zhang