An assessment of analysis performance

"Previous lectures in this series have discussed the theory and application of the NMC global data assimilation system, as well as its antecedents and the data base it is asked to assimilate. The series concludes with this examination of the performance of the system in operational practice. A variety of statistical measures have been monitored routinely since the system was implemented in September 1978. Some of these are presented in the next section. For comparison, similar statistics from the previous system based on the Hough function spectral objective analysis are included. A third section discusses the large-scale characteristics of the system in terms of zonally-averaged profiles of certain quantities such as zonal and meridional wind components, temperature, and moisture. These are compared to analogous quantities from climatology. The fourth section illustrates specific examples of system performance as seen in a particular case. Vertical structure, relationship between mass and motion fields, and representation of extrema are examined along with a general discussion of the character, advantages, and disadvantages of the analyzed fields. Examples are given separately in the Northern and Southern Hemispheres and the Tropics"--Introduction. Ronald D. McPherson. "July 1980." "This is an unreviewed manuscript, primarily intended for informal exchange of information among NMC staff members." System requirements: Adobe Acrobat Reader. Includes bibliographical references (page 30). 1980 NWS (National Weather Service) NCEP (National Centers for Environmental Prediction) Library Public Domain 2285