edu.ucar.opensky::articles:17476 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T15:08:55.916042 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7bg2q9j Test of a non-local excess phase delay operator for GPS radio occultation data assimilation 2009-02-12T00:00:00Z publication https://n2t.org/ark:/85065/d7bg2q9j https://doi.org/10.1117/1.3094060 Shao, Hui author Zou, X. author Hajj, G. author UCAR/NCAR - Library publisher A physically-sound, non-local excess phase delay observation operator is developed for simulating excess phase delay measurements from GPS radio occultation (RO) missions. By approximating an observed ray by a straight line, the refractivity gradient information along an observed ray path is included in the simulated excess phase delay. This observation operator is used to simulate observations from the German CHAllenging Minisatellite Payload (CHAMP) RO mission based on large-scale analysis. The need to use such an observation operator for GPS RO data assimilation in spherically asymmetric regions is shown by results from a set of forward simulation and data assimilation experiments. A modification that renders the non-local excess phase delay observation operator more suitable for parallel implementation of GPS RO data assimilation is proposed. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. None eng geoscientificInformation