Xiaozhen (Shawn) Xiong received his Ph.D. degree in atmospheric sciences from University of Alaska Fairbanks (UAF) in 2000. After a short stay as a postdoctoral fellow at Geophysical Institute of UAF to continue his research on polar remote sensing of cloud, aerosol and snow/ice surface properties, he started to work as a research scientist/contractor supporting NOAA/NESDIS/Center for Satellite Applications and Research (STAR) in 2001, and joined ESSIC/CICS as an Associate Research Scientist in 2017. From 2001-2004 his studies focused on the development of fast radiative transfer model, Optical Path Transmittance (OPTRAN), for hyperspectral infrared and microwave data assimilation. Since 2005 his studies have focused on the development of inverse algorithms to retrieve atmospheric temperature, water vapor and trace gases profiles using the different hyperspectral sensors, such as the Atmospheric Infrared Sounder (AIRS) on NASA/Aqua, the Infrared Atmospheric Sounding Interferometer (IASI) on Metop–A, –B, and the Cross-track Infrared Sounder (CrIS) on S-NPP and JPSS. His major contributions are the development of methane (CH4) and Nitrous Oxide (N2O) retrieval algorithms for AIRS (V5 & V6) and NOAA Unique Combined Atmospheric Processing system (NUCAPS), as well as the validation and usage of these products for environmental and climate study. For about two years from 2014-2016 he also worked on the CrIS calibration team, specializing on the near-real time processing of CrIS full spectral data SDR data, delivery and data management. His current major research interests are to use satellite-derived atmospheric compositions products, including aerosol and trace gases, to study air pollution, dynamic transport of trace gases in the atmosphere, and the spatial variation of greenhouses gases, emissions and trends for climate change study. As a result of his satellite data studies, he has found: the CH4 plume in the upper troposphere over south Asia during the monsoon season, the opposite seasonal cycle of CH4 in the upper troposphere in the Arctic due to the summer emission from wetlands and thawing permafrost and upward transport, the depletion of CH4 associated with stratospheric intrusion, and the capability of AIRS to monitor the long-term increase of N2O. He has published over 40 papers in peer-reviewed journals.