Jet Stream Winds: Comparisons of Aircraft Observations with Analyses

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  • 1 State University of New York at Purchase, Purchase, New York
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Abstract

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 four of the major operational centers show that the peak analyzed winds are still too weak by about 10%. In addition, about 17% of the cases show larger errors in which the analyses substantially miss the location or magnitude of individual jet streaks. Both the aircraft data and the highest-resolution analysis (European Centre for Medium-Range Weather Forecasts, equivalent equatorial quarter-wave grid spacing of 47 km) show evidence of orographically generated gravity waves but differ in their vertical damping.

Abstract

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 four of the major operational centers show that the peak analyzed winds are still too weak by about 10%. In addition, about 17% of the cases show larger errors in which the analyses substantially miss the location or magnitude of individual jet streaks. Both the aircraft data and the highest-resolution analysis (European Centre for Medium-Range Weather Forecasts, equivalent equatorial quarter-wave grid spacing of 47 km) show evidence of orographically generated gravity waves but differ in their vertical damping.

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