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Development of an Operational Hybrid Data Assimilation System at KIAPS

  • In-Hyuk Kwon
  • Hyo-Jong Song
  • Ji-Hyun Ha
  • Hyoung-Wook Chun
  • Jeon-Ho Kang
  • Sihye Lee
  • Sujeong Lim
  • Youngsoon Jo
  • Hyun-Jun Han
  • Hanbyeol Jeong
  • Hui-Nae Kwon
  • Seoleun Shin
  • Tae-Hun Kim
Article
  • 29 Downloads

Abstract

This study introduces the operational data assimilation (DA) system at the Korea Institute of Atmospheric Prediction Systems (KIAPS) to the numerical weather prediction community. Its development history and performance are addressed with experimental illustrations and the authors’ previously published studies. Milestones in skill improvements include the initial operational implementation of three-dimensional variational data assimilation (3DVar), the ingestion of additional satellite observations, and changing the DA scheme to a hybrid four-dimensional ensemble-variational DA using forecasts from an ensemble based on the local ensemble transform Kalman filter (LETKF). In the hybrid system, determining the relative contribution of the ensemble-based covariance to the resultant analysis is crucial, particularly for moisture variables including a variety of horizontal scale spectra. Modifications to the humidity control variable, partial rather than full recentering of the ensemble for humidity further improves moisture analysis, and the inclusion of more radiance observations with higher-level peaking channels have significant impacts on stratosphere temperature and wind performance. Recent update of the operational hybrid DA system relative to the previous 3DVar system is described for detailed improvements with interpretation.

Key words

Numerical weather prediction operational data assimilation ensemble-variational hybridization satellite observation assimilation coupling strategy for hybrid systems 

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Copyright information

© Korean Meteorological Society and Springer Nature B.V. 2018

Authors and Affiliations

  • In-Hyuk Kwon
    • 1
  • Hyo-Jong Song
    • 1
    • 2
  • Ji-Hyun Ha
    • 1
  • Hyoung-Wook Chun
    • 1
  • Jeon-Ho Kang
    • 1
  • Sihye Lee
    • 1
  • Sujeong Lim
    • 1
  • Youngsoon Jo
    • 1
  • Hyun-Jun Han
    • 1
  • Hanbyeol Jeong
    • 1
  • Hui-Nae Kwon
    • 1
  • Seoleun Shin
    • 1
  • Tae-Hun Kim
    • 1
  1. 1.Korea Institute of Atmospheric Prediction Systems (KIAPS)SeoulKorea
  2. 2.Korea Institute of Atmospheric Prediction SystemsSeoulKorea

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