Turbulence measurementsby the DC-8 meteorological measurement system
The instrumentation of a new MMS on the NASA DC-8 aircraft is briefly described.A methodto computethe turbulent dissipationrate, e, is discussedin light of some apparentinconsistencies betweenhigh and medium altitude aircraft data and available theory. Examples of turbulence measurements during encountersof a wake vortex, a field of wave clouds,and persistentcontrailsare illustrated. 1. DC-8 MMS: Instrumentation and Accuracy The MeteorologicalMeasurementSystem(MMS), developedspecificallyfor the DC-8 aircraft,was a new instrument duringthe SubsonicContrailand CloudEffect SpecialStudy (SUCCESS)campaignin 1996. The DC-8 MMS is verysimilar to an instrumentdevelopedfor the ER-2 aircraft(Chanet al., 1989). In additionto pressure(p), temperature(T), and wind vector(u, v, w), we computeda dissipationrate, e, basedon ity by spectralanalysis. The calibrationconsistsof eliminating inducedperturbationsin the wind componentsduring aircraftmaneuvers.