Atmosphere Ocean Science Colloquium

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ENSO in climate models: Progress and Opportunities

Speaker: Andrew T. Wittenberg, NOAA

Location: Warren Weaver Hall 1302

Date: Wednesday, May 16, 2018, 3:30 p.m.

Synopsis:

The El Niño / Southern Oscillation (ENSO) is Earth's strongest interannual climate fluctuation, with impacts on extreme weather, agriculture, fisheries, ecosystems, and economies worldwide.  Coupled general circulation models (CGCMs) are indispensable tools for forecasting ENSO, for illuminating ENSO dynamics, and for projecting the future of ENSO in the context of a changing climate.  Recent advances in CGCMs have led to improved understanding of ENSO's precursors, impacts, nonlinearities, spatiotemporal diversity, and interdecadal modulation, and will soon enable seamless subseasonal-to-decadal predictions.  Yet despite this impressive progress, several major challenges remain for CGCMs: persistent biases in the tropical Pacific mean climate, displaced patterns of ENSO's variability and teleconnections, altered feedback loops, and insufficient diversity, asymmetry, and seasonal synchronization of ENSO.  Such model biases can then degrade historical climate reanalyses, generate initialization shocks and conditional biases in forecasts, and undermine confidence in model projections of ENSO's future.  I will discuss community-wide efforts to tackle these problems, supported by strengthening connections among observations, theory, and numerical models.  I will also highlight recent progress at NOAA GFDL toward simulating and understanding ENSO, offering exciting new avenues to further improve predictions of tropical Pacific climate variations and their global impacts.