edu.ucar.opensky::articles:12269 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T03:46:42.535724 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d761113g Indirect assimilation of radar reflectivity with WRF 3D-Var and its impact on prediction of four summertime convective events 2013-04-01T00:00:00Z publication https://n2t.org/ark:/85065/d761113g https://doi.org/10.1175/JAMC-D-12-0120.1 Wang, Hongli author Sun, Juanzhen author Fan, S. author Huang, Xiang-Yu author UCAR/NCAR - Library publisher An indirect radar reflectivity assimilation scheme has been developed within the Weather Research and Forecasting (WRF) model three-dimensional data assimilation system (WRF 3D-Var). This scheme, instead of assimilating radar reflectivity directly, assimilates retrieved rainwater and estimated in-cloud water vapor. An analysis is provided to show that the assimilation of the retrieved rainwater avoids the linearization error of the Z-qr (reflectivity-rainwater) equation. A new observation operator is introduced to assimilate the estimated in-cloud water vapor. The performance of the scheme is demonstrated by assimilating reflectivity observations into the rapid update cycle (RUC) data assimilation and forecast system operating at Beijing Meteorology Bureau. Four heavy-rain-producing convective cases that occurred during summer 2009 in Beijing, China are studied using the newly developed system. Results show that on average the assimilation of reflectivity significantly improves the short-term precipitation forecast skill up to 7 hours. A diagnosis of the analysis fields of one case shows that the assimilation of reflectivity increases humidity, rainwater and convective available potential energy (CAPE) in the convective region. As a result, the analysis successfully promotes the developments of the convective system, and thus improves the subsequent prediction of the location and intensity of precipitation for this case. 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 2012 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