Chen, Mei-Hsin, Chin-Tzu Fong, Central Weather
Bureau, Taiwan and Yong-Run Guo, NCAR, USA.
This study reviewed the
characteristics of background error covariance option 3 (CV3 BE) in WRFDA
(Weather Research and Forecasting model data assimilation system), and its
applications in CWB (Central Weather Bureau). CWB has used WRFDA with CV3 BE as
its three-dimensional variational data assimilation analysis system for more
than two years. The CV3 BE has been tuned in CWB WRFDA to adjust the forecast
error distribution. In this year, outer-loops were implemented into the
operational system. This study explains the benefits of using outer-loops,
especially for typhoon cases. The future work on CV3 BE in CWB WRFDA will be
mentioned in the end.