Evaluation of the Advanced Hurricane WRF Data Assimilation System for the 2009 Atlantic hurricane season

AMS Citation:
Cavallo, S. M., R. D. Torn, C. M. Snyder, C. A. Davis, W. Wang, and J. M. Done, 2013: Evaluation of the Advanced Hurricane WRF Data Assimilation System for the 2009 Atlantic hurricane season. Monthly Weather Review, 141, 523-541, doi:10.1175/MWR-D-12-00139.1.
Resource Type:article
Title:Evaluation of the Advanced Hurricane WRF Data Assimilation System for the 2009 Atlantic hurricane season
Abstract: Real-time analyses and forecasts using an ensemble Kalman filter (EnKF) and the Advanced Hurricane Weather Research and Forecasting Model (AHW) are evaluated from the 2009 North Atlantic hurricane season. This data assimilation system involved cycling observations that included conventional in situ data, tropical cyclone (TC) position, and minimum SLP and synoptic dropsondes each 6 h using a 96-member ensemble on a 36-km domain for three months. Similar to past studies, observation assimilation systematically reduces the TC position and minimum SLP errors, except for strong TCs, which are characterized by large biases due to grid resolution. At 48 different initialization times, an AHW forecast on 12-, 4-, and 1.33-km grids is produced with initial conditions drawn from a single analysis member. Whereas TC track analyses and forecasts exhibit a pronounced northward bias, intensity forecast errors are similar to (lower than) the NWS Hurricane Weather Research Model (HWRF) and GFDL forecasts for forecast lead times ≤60 h (>60 h), with the largest track errors associated with the weakest systems, such as Tropical Storm (TS) Erika. Several shortcomings of the data assimilation system are addressed through postseason sensitivity tests, including using the maximum 800-hPa circulation to identify the TC position during assimilation and turning off the quality control for the TC minimum SLP observation when the initial intensity is far too weak. In addition, the improved forecast of TS Erika relative to HWRF is shown to be related to having initial conditions that are more representative of a sheared TC and not using a cumulus parameterization.
Peer Review:Refereed
Copyright Information:Copyright 2013 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.
OpenSky citable URL: ark:/85065/d70p10t5
Publisher's Version: 10.1175/MWR-D-12-00139.1
  • Steven Cavallo - NCAR/UCAR
  • Ryan Torn
  • Chris Snyder - NCAR/UCAR
  • Christopher Davis - NCAR/UCAR
  • Wei Wang - NCAR/UCAR
  • James Done - NCAR/UCAR
  • Random Profile


    Recent & Upcoming Visitors