Improving the Observation Operator for the Phased Array Weather Radar in the SCALE-LETKF System

DOI Web Site 被引用文献3件 参考文献18件
  • Amemiya Arata
    RIKEN Center for Computational Science (R-CCS) RIKEN Cluster for Pioneering Research
  • Honda Takumi
    RIKEN Center for Computational Science (R-CCS) RIKEN Cluster for Pioneering Research
  • Miyoshi Takemasa
    RIKEN Center for Computational Science (R-CCS) RIKEN Cluster for Pioneering Research

抄録

<p>The observation operator for the Phased Array Weather Radar in the SCALE-LETKF data assimilation system is revisited, and the impact of its improvement on the analyses and forecasts is examined. The observation operator provides a functional relationship between equivalent radar reflectivity factor (Ze) and hydrometeor mass density (W) of each precipitation particle category. The W–Ze relationship is obtained by a radar simulator. This study performs a radiation code calculation with the parameters regarding particle size distribution of graupel consistent with the cloud microphysics scheme in the SCALE model. The newly obtained observation operator provides much stronger sensitivity of graupel mixing ratio to observed Ze compared to the operator originally used in the model. To examine the impact on the SCALE-LETKF analyses and forecasts, an experiment on a 13 July 2013 heavy rain case is performed with the new observation operator and is compared with the previous study. The forecast initiated by the analysis using the new operator shows much more realistic evolution of Ze in the middle troposphere, where a large amount of graupel is located. The overestimation of forecast Ze is significantly alleviated by the new observational operator. The 30-minute forecast of surface precipitation rate is also improved. </p>

収録刊行物

  • SOLA

    SOLA 16 (0), 6-11, 2020

    公益社団法人 日本気象学会

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