Join us for a presentation by Dr. Sonia Kreidenweis and Dr. Peter Jan van Leeuwen, two professors from Colorado State University, whose talk is titled "Data assimilation for GESTAR II science." Dr. Kreidenweis is a University Distinguished Professor of Atmospheric Science and serves as the CSU liaison to GESTAR II. Dr. van Leeuwen is a Professor of Data Assimilation and Nonlinear Dynamics in the Department of Atmospheric Science.
Date and Time: Tuesday, May 24, 2022 at 2:00pm
Join us via Teams.
Abstract:
Data assimilation is the science, or art, of combining information from observations with numerical models to provide better forecasts, improve models, and improve system understanding. Present-day operational data assimilation is based on linearized methods, such as Ensemble Kalman filters and 3D- and 4DVar, while parts of the atmosphere display highly nonlinear dynamics, such as cloud processes and intense tropical cyclones. Furthermore, current methods rely on assuming Gaussian observation errors, and largely ignore errors in the model equations. In this talk I will discuss exciting new developments in nonlinear data-assimilation, and in using data assimilation to estimate non-Gaussian observation errors and model errors. Furthermore, an example of how data assimilation can be used in combination with a newly developed causal discovery method to unravel the physics of Hurricane Rapid Intensification will be presented.
Biographies:
Sonia Kreidenweis is a University Distinguished Professor of Atmospheric Science at CSU. Her research focuses on characterization of the physical, chemical, and optical properties of atmospheric particulate matter, and the effects of the atmospheric aerosol on visibility and climate. Ongoing laboratory and field studies have investigated the role of particle types and of individual compounds found in particulate matter in the nucleation of cloud droplets and ice crystals and initiation of precipitation.
Peter Jan van Leeuwen is Professor of Data Assimilation and Nonlinear Dynamics in the Department of Atmospheric Science and joined CSU in 2018. Before that he worked at the University of Reading, UK, and at the University of Utrecht in the Netherlands, and served as the Director of the Data Assimilation Research Centre. His research group works on pushing data assimilation into the fully nonlinear regime for atmospheric and oceanic problems. Furthermore, he has developed a fully nonlinear causal discovery methodology to analyze the causal pathways of complex nonlinear processes such as Hurricane Rapid Intensification, cloud dynamics and ocean dynamics. He also explores dynamical systems theory to investigate cloud evolution and cloud aggregation processes, and develops methods to investigate how information flows in complex numerical models to understand how different physical processes communicate with each other.
For more information on the GESTAR II Seminar Series, click here.