The NCEP Global Analysis System : Recent Improvements and Future Plans (gtSpecial IssueltData Assimilation in Meteology and Oceanography: Theory and Practice)

• DOI: 10.2151/jmsj1965.75.1b_359
• Publication Date: 2017-04-18T22:09:44Z
• Authors: David F. Parrish; John C. Derber; R. James Purser; Wan-Shu Wu; Zhao-Xia Pu
• Keywords: Geopotential height; Divergence (linguistics); Anomaly (physics); Geopotential

This paper describes significant changes to the U.S. National Centers for Environmental Prediction (NCEP, formerly NMC, Meteorological Center) global data assimilation system that were made operational in January, 1995. The emphasis is on 3D-variational analysis, which has been running operationally since June, 1991. include additions of new types, modifications background error, and addition a weak constraint divergence tendency. A uniform improvement fit 6 hour forecast guess all observation types was observed parallel tests over period 9 months. Most believed be due tendency constraint. improved performance extends medium range forecasts, as measured by anomaly correlation scores geopotential height. Current research activities related regional at NCEP are also briefly described.