edu.ucar.opensky::articles:17363 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T15:00:38.929569 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7xs5wqh Comparison of local and nonlocal observation operators for the assimilation of GPS RO data with the NCEP GSI system: An OSSE study 2009-10-01T00:00:00Z publication https://n2t.org/ark:/85065/d7xs5wqh https://doi.org/10.1175/2009MWR2809.1 Ma, Zaizhong author Kuo, Ying-Hwa author Wang, B. author Wu, W. author Sokolovskiy, Sergey author UCAR/NCAR - Library publisher In this study, an Observing System Simulation Experiment (OSSE) is performed to evaluate the performance of a nonlocal excess phase operator and a local refractivity operator for a GPS radio occultation (RO) sounding that passes through the eye of Hurricane Katrina as simulated by a high-resolution model, with significant horizontal refractivity gradients. Both observation operators are tested on the NCEP gridpoint statistical interpolation (GSI) data assimilation system at 12- and 36-km horizontal resolution. It is shown that the shape and magnitude of the analysis increments for sea level pressure, temperature, and water vapor mixing ratio exhibit significant differences between the use of local and nonlocal operators. The nonlocal operator produces more accurate analyses when verified against the "truth" derived from the ground truth run. It is found that the improvements of the analysis with the use of the nonlocal operator over that of the local operator are essentially the same at 12- and 36-km horizontal resolution. An additional experiment is performed over a region with small horizontal gradients. As expected, the use of both nonlocal and local operators produces similar results over such a region. 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 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. None eng geoscientificInformation