Monday, 12 January 2004
The RUC 3dvar: Operational performance and recent improvements
The Rapid Update Cycle (RUC) is a high-frequency (hourly) data assimilation and forecasting system developed at the Forecast Systems Laboratory and run operational at the National Centers for Environmental Predictions (NCEP). In May 2003 the optimum interpolation (OI) analysis formerly used in the RUC was replaced by a 3dvar analysis. The 3dvar method follows the basic design of OI, but produces less noisy analyses and uses less computer time. Operational performance statistics from the RUC 3dvar will be presented in detail. We will also discuss new features and improvements that have been developed, including re-computation of background error covariances, improvement of the precipitable water vapor analysis, and observation processing in atmospheric boundary layer, etc. Future plans including evolution toward the WRF 3dvar will be outlined.