Hui Liu is a Visiting Associate Research Scientist who joined ESSIC in October 2017. Before that, he was a Project Scientist at the National Center for Atmospheric Research from 2003 to 2017 and a Research Associate at Florida State University from 1998 to 2003. His work had focused on improving assimilation of GPS radio occultation data in the tropical troposphere, including developments of physics-based quality controls and dynamic errors of radio occultation data, as well as 2D non-local observation operators. Since 2019, he is working on a NOAA/NESDIS/STAR project entitled "Evaluation of the Impact of the European Space Agency's Aeolus Space Lidar Wind Observations on NCEP Global Forecast". This project is expected to help promote NOAA's mission of using space lidar to provide global wind observations. Dr. Liu got his Ph.D. from the Chinese Academy of Sciences in Beijing in 1993 and moved to U.S. in 1998.