Multi-Scale EnKF Assimilation of Radar and Conventional Observations and Ensemble Forecasting for a Tornadic Mesoscale Convective System
نویسندگان
چکیده
In recent studies, the authors have successfully demonstrated the ability of an ensemble Kalman filter (EnKF), assimilating real radar observations, to produce skillful analyses and subsequent ensemble-based probabilistic forecasts for a tornadic mesoscale convective system (MCS) that occurred over Oklahoma and Texas on 9 May 2007. The current study expands upon this prior work, performing experiments for this case on a larger domain using a nested-grid EnKF which accounts for mesoscale uncertainties through the initial ensemble and lateral boundary condition perturbations. In these new experiments, conventional observations (including surface, wind profiler, and upper-air observations) are assimilated in addition to the WSR-88D and CASA radar data used in the previous studies, better representing meso-and convective-scale features. The relative impacts of conventional and radar data on analyses and forecasts are examined, and biases within the ensemble are investigated. Compared to prior results, the radar-assimilating experiments accounting for mesoscale uncertainties produce superior forecasts based on both subjective and objective verification metrics. The new experiments produce a substantially-improved forecast, including better representation of the convective lines of the MCS. Assimilation of radar data substantially improves the ensemble precipitation forecast. Assimilation of conventional data together with radar observations substantially improves the forecast of near-surface mesovortices within the MCS, improves forecasts of surface temperature and dewpoint, and imparts a slight but noticeable improvement to short-term precipitation forecasts. Furthermore, ensemble analyses and forecasts are found to be sensitive to the localization radius applied to conventional data within the EnKF.
منابع مشابه
Ensemble Probabilistic Forecasts of a Tornadic Mesoscale Convective System from Ensemble Kalman Filter Analyses using WSR-88D and CASA Radar Data
This study examines the ability of a storm-scale numerical weather prediction (NWP) model to predict precipitation and mesovortices within a tornadic mesoscale convective system that occurred over Oklahoma on 8–9 May 2007, when the model is initialized from ensemble Kalman filter (EnKF) analyses including data from four Engineering Research Center for Collaborative Adaptive Sensing of the Atmos...
متن کاملAnalysis of a Tornadic Meoscale Convective Vortex Based on Ensemble Kalman Filter Assimilation of CASA X-band and WSR-88D Radar Data
ii Abstract One of the goals of the National Science Foundation Engineering Research Center (ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) is to improve storm-scale numerical weather prediction (NWP) by collecting data with dense X-band radar network which provides high-resolution low-level coverage, and by assimilating such data into NWP models. During the first spring storm...
متن کاملAnalysis of a Tornadic Mesoscale Convective Vortex Based on Ensemble Kalman Filter Assimilation of CASA X-Band and WSR-88D Radar Data
One of the goals of the National Science Foundation Engineering Research Center (ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) is to improve storm-scale numerical weather prediction (NWP) by collecting data with a dense X-band radar network that provides high-resolution low-level coverage, and by assimilating such data into NWP models. During the first spring storm season aft...
متن کاملUniversity of Oklahoma Graduate College Assimilation of Casa and Wsr-88d Radar Data for Tornadic Convective Storms Using an Ensemble Kalman Filter and Applications in Probabilistic Ensemble Forecasting
متن کامل
ERAD 2012 - THE SEVENTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY EnKF assimilation of storm-scale, mobile Doppler radar data for high-resolution analyses of a weakly tornadic supercell
Recent efforts to include mobile and other non-standard ground-based radar data in ensemble analyses of severe convective storms have yielded promising results (e.g., Marquis et al. 2010; Snook et al. 2011; Tanamachi et al. 2012). During Project VORTEX2 (Wurman et al. 2010), the field phase of which occurred in spring 2009 and spring 2010, coordinated mobile Doppler radar deployments resulted i...
متن کامل