报告题目：Shipborne GNSS Contributing To Ocean Observing System（船载GNSS在海洋观测中的应用） 
报告人：Jungang Wang, Deutsches GeoForschungsZentrum GFZ, Potsdam, Germany; Technical University of Berlin, Germany 
时间：2019年2月20日（周三）10：00 
地点：天文大厦三楼中会议室 
Abstract: 
Ground-based Global Navigation Satellite System (GNSS) receivers have been widely installed over land and used in precise geophysical signals retrieval, atmosphere sounding, et al. In the vast ocean, however, the GNSS applications are still limited. We demonstrated the sea surface height (SSH) determination and atmosphere sounding with kinematic Precise Point Positioning (PPP) technique using 20-day shipborne GNSS observations in Fram Strait, the gateway to the Arctic between Greenland and Svalbard. The 1-Hz ellipsoidal height estimates of shipborne GNSS antenna was obtained in post-processing mode, and special efforts were made for the correction of ship hydrostatic and hydrodynamic effects to derive the SSH estimates. The average and median values of short-term position precision of the 1-Hz SSH was 7.91 cm and 3.68 cm respectively, and the 1-hour averaged mean sea surface (MSS) along the ship track was achieved with an accuracy of 7.3 cm compared with CNES CLS 2015 MSS model. The residuals were analyzed together with the sea state and the limitation of the MSS model in the coastal regions was revealed. Further study was made for the Precipitable Water Vapor (PWV) retrieval, and an accuracy of ~1 mm was achieved compared to the coastal ground-based GNSS receivers, the radiosonde stations, the Numerical Weather Model (NWM), and the satellite altimetry observations. An improvement of ~10% in PWV retrieval was demonstrated with multi-GNSS solution compared to the GPS-only one. Compared to the traditional satellite altimetry, shipborne GNSS provides precise SSH estimates with high spatial/temporal resolutions, and covers the Polar Regions and coastal regions where the satellite altimetry cannot work due to the ice/land contamination. Shipborne GNSS atmosphere sounding also fills in the ocean region in NWM assimilation and provides valuable information for weather nowcasting and climate research. 
Resume 
Jungang Wang was born in 1990. He received his B.S. degree in Surveying and Mapping in 2013 from Tongji University, Shanghai. Since 2013, he worked as a research assistant in Tongji University and Shanghai Astronomical Observatory, and received his M.S. degree in Geodesy in 2016 from Tongji University. He worked as a research assistant in the Hong Kong Polytechnic University (PolyU) in 2015-2016. Currently, he is working toward the Ph.D. degree in Geodesy, in DeutschesGeoForschungsZentrum (GFZ) & Technische Universit？t Berlin (TUB), Germany. His research interests are in Multi-GNSS data processing and applications, troposphere delay and ionosphere delay modeling in geodetic techniques, and the combination of GNSS, SLR, and VLBI measurements.