JET-STREAM WINDS - COMPARISONS OF AIRCRAFT OBSERVATIONS WITH ANALYSES

Wind measurements have been obtained from commercial aircraft crossing the 1992 winter subtropical jet streams over southwest and east Asia. Comparisons of these data with new, high resolution analyses from fou r of the major operational centers show that the peak analyzed winds a re still too weak by about 10%. In addition, about 17% of the cases sh ow larger errors in which the analyses substantially miss the location or magnitude of individual jet streaks. Both the aircraft data and th e highest-resolution analysis (European Centre for Medium-Range Weathe r Forecasts, equivalent equatorial quarter-wave grid spacing of 47 km) show evidence of orographically generated gravity waves but differ in their vertical damping.