Date:    6 August 2025 (Wednesday)
Time:    2:00pm – 3:00pm
Venue:    Room 4504 (Lift 25 – 26)

Abstract:
Earth system models (ESMs) are composed of different parametrization schemes that simulate different processes such as water and energy fluxes on land surface, atmospheric and ocean circulations, radiation transfer, and the interactions between land, atmosphere and oceans. Those parameterization schemes contain many parameters that are not observable, but are critically important to the performance of ESMs. Quantification and reduction of ESM parametric uncertainties are an essential step in recasting of the historical processes and in projecting the future processes of the Earth system. In this talk, I will overview how we can use systematic uncertainty quantification approaches to reduce parametric uncertainties. Different techniques such as designs of experiments, global sensitivity analysis, surrogate models and automatic optimization methods will be briefly reviewed and how those techniques can be used to improve ESM simulations will be showcased.

Biography:
Professor Qingyun Duan, who received his Ph.D. in hydrology from the University of Arizona in 1991, worked for NOAA Hydrology Laboratory and Lawrence Livermore National Laboratory in the US from 1991 to 2009. He returned to China to work for Beijing Normal University between 2009 and 2019. He has been a Chair Professor in the College of Hydrology & Water Resources at Hohai University in Nanjing since 2019. His research interests include hydrometeorological modeling and uncertainty quantification, ensemble forecasting, and climate change impact on hydrology and water resources. He has published 230 peer reviewed articles and edited 4 books in hydrology and water resources. Dr. Duan is the President of Hydrological Science Section of Asia Oceania Geoscience Society. He serves as the Editor-in-Chief for Reviews of Geophysics and Hydrology Editor of Bulletin of American Meteorological Society. He was also the Editor-in-Chief of the Springer major reference book “Handbook of Hydrometeorological Ensemble Forecasting”. Dr. Duan is a Fellow of American Geophysical Union and American Meteorological Society.