Research Oceanographer, Gabriel Vecchi, will give three seminars on Atmospheric Nonlinerarity in El Nino, Seasonal Hurricane Prediction, and Global High-Resolution Coupled Modeling.
October 15th, 2014 at 10am in MIT 54-915
The El Niño-Southern Oscillation (ENSO) phenomenon is the largest mode of year-to-year variability in the climate system, involving large redistribution of rainfall and oceanic waters in the tropical Pacific and influencing weather and ecosystems throughout the globe. This lecture will discuss the character and mechanisms for ENSO, focusing principally on the role of the non-linear relationship between atmospheric convection and sea surface temperatures on the character of ENSO. Analysis of observations, as well as of conceptual and climate models, shows the role of atmospheric nonlinearity in El Niño onset and termination, key differences between moderate amplitude and extreme El Niño events, and aspects of the asymmetry between positive and negative phases of ENSO. Implications of these atmospheric nonlinearities for the prediction of El Niño and its impacts, and for understanding the response of El Niño to altered climates, will also be discussed.
October 22nd, 2014 at 10am in MIT 54-915
Tropical cyclones are a major hazard and an energetic element of the climate system. There are thus both societal and scientific drivers to understand and predict the year-to-year variations of tropical cyclone activity, in order to support decisions and to test the hypotheses underlying the prediction methodologies. Predictions of tropical cyclone activity aggregated over an entire basin (e.g., the North Atlantic) from months prior to the tropical cyclone season are generated regularly, and even show some measure of skill. However, for many downstream applications information at a more regional scale is necessary. In addition, regional prediction targets allow for more refined assessment of prediction methodologies. This lecture will introduce a new experimental high-resolution seasonal prediction system that enables the skillful prediction of regional tropical cyclone activity across much of the Northern Hemisphere months and seasons in advance. Key limitations and steps to improve these promising results will also be discussed.
October 29th, 2014 at 10am in MIT 54-915
Global climate models at increasingly refined resolutions are being run across the world, and provide unique tools to understand the sensitivity of tropical cyclones to climatic variations and changes, as well as the roles of tropical cyclones in the climate system. A new family of high-resolution coupled ocean-atmosphere-land-ice models is used to explore the response of tropical cyclones, both globally and regionally, to increasing greenhouse gases and to internal climate variations. The response of the total number and the total power dissipation index of tropical cyclones to increasing greenhouse gases can differ substantially between models of two atmospheric resolutions, 50km and 25km. Some thoughts on the reasons behind those differences will be offered. Systematic errors in simulating the large-scale climate are a key limitation in the models' abilities to simulate tropical cyclones and their response to variations of the climate system.
Gabriel Vecchi is a Research Oceanographer and the Head of the Climate Variations and Predictability Group at the Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, New Jersey, where he has been since 2003. The focus of his research is the interactions between the atmosphere and oceans on time scales from weeks to centuries, including the El Niño-Southern Oscillation phenomenon, tropical cyclones and the Asian-Australian monsoon. Gabriel’s recent efforts concentrate on predicting short- and long-term changes to tropical circulation and variability, including characterizing the impact of climate change on tropical cyclones and hurricanes, and global patterns of rainfall and drought.
Gabriel currently serves as the co-chair of the U.S.-Climate Variability and Predictability (CLIVAR) Working Group on Hurricanes and Climate; he also serves as a member of NOAA’s Climate Observing Systems Council, and was a Lead Author in Working Group I of the IPCC Fifth Assessment Report. He is an Associate Editor of the Journal of the Atmospheric Sciences and the Journal of Climate. In the past he served on the CLIVAR Asian-Australian Monsoon Panel, CLIVAR Indian Ocean Panel, and the U.S.-CLIVAR Predictability, Prediction, and Applications Interface Panel. He has authored over 100 papers for scientific journals and book chapters.
Gabriel is the recipient of the U.S. Presidential Early Career Award for Scientists and Engineers (PECASE), the American Meteorological Society’s Clarence Leroy Meisinger Award, the US Department of Commerce Gold Medal, the NOAA-OAR Outstanding Paper of the Year Award, the NOAA Administrator’s Award, the American Geophysical Union’s Editor's Citation for Excellence in Refereeing for Geophysical Research Letters (twice), and the Cook College, Rutgers University Marine Sciences Student of the Year. Gabriel earned a Ph.D. in Oceanography from the University of Washington, as well as M.S. degrees in Oceanography and Applied Mathematics. His undergraduate degree in Mathematics is from Rutgers University.