EVALUATION OF NMC UPPER-STRATOSPHERIC TEMPERATURE ANALYSES USING ROCKETSONDE AND LIDAR DATA

Daily NMC analyses, constructed from operational TOVS data since 1978, are used to monitor behavior of middle atmospheric temperature. Capab ility of the upper-stratospheric analyses (5,2,1 and 0.4 mb) to provid e temporally consistent temperature fields depends on adjustments deri ved from ground-truth observations. These adjustments compensate for b iases in the analyses caused by behavioral differences in data derived from successive operational satellite instruments and by changes in d ata and analysis procedures. This paper supports previous studies show ing that observations from the datasonde rocket system provide ground- truth adjustments with a precision of 1-degrees-3-degrees-C. The numbe r of datasonde observations has diminished substantially in recent yea rs, putting this adjustment system at risk. Falling-sphere rocket temp erature data are shown to have variability in excess of that judged to be acceptable for use in the adjustment system. The capability tor Ra yleigh lidar to provide high-quality temperature data needed tor groun d truth is examined by comparing NMC analysis temperatures, adjusted b y datasonde measurements, with observational values from regularly ope rating lidar systems in France since 1978. Agreement between the two d atabases is found to be good in recent years. This is further verified by comparisons between the datasonde-computed adjustments and indepen dent analysis adjustments derived from the lidar database. It is concl uded that high-quality lidar measurements, if made available from low, medium, and high latitudes, could provide the essential data for use in the analysis adjustment system.