Atmosphere Ocean Science Colloquium
Coupled Air-Sea Modeling and Data Assimilation for Tropical Cyclone Prediction
Speaker: Xingchao Chen, Penn State
Location: Warren Weaver Hall 1302
Date: Wednesday, February 26, 2020, 3:30 p.m.
Tropical cyclones (TCs) are one of the most devastating and frequently occurring natural disasters, causing catastrophic damage to coastal areas by producing extreme wind, rainfall, storm surge, and flooding. Accurate prediction of TC track and intensity can have enormous societal and economic impacts. In this talk, I will discuss the most recent advances in modeling and data assimilation (DA) for TC prediction. In particular, an air-sea fully coupled TC DA system based on the ensemble Kalman filter (EnKF) will be introduced. Through the flow-dependent covariance both within and across the oceanic and atmospheric domains, the fully coupled DA system is capable of updating both atmospheric and oceanic state variables simultaneously by assimilating either atmospheric and/or oceanic observations. Observing system simulation experiments (OSSEs) show that assimilation of oceanic observations not only resulted in better analysis and forecast of the oceanic variables, but also considerably reduced analysis and forecast errors in the atmospheric fields, including the intensity and structure of TC. Compared to weakly coupled DA in which the analysis update is performed separately for the atmospheric and oceanic domains, fully coupled DA reduces the forecast errors of tropical cyclone track and intensity. Results show promise in potential further improvement in TC prediction through assimilation of both atmospheric and oceanic observations using the ensemble-based fully coupled DA system.