Joint Agency Turbulence Experiment.
Environmental research papers,
AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
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Doppler radar data acquired during the 1981 Joint Agency Turbulence Experiment are presented. Pulse-pair processed reflectivity factor and Doppler spectrum mean data collected during volume scan periods are displayed over constant height surfaces at aircraft penetration level. Time histories of tracking-gate Doppler spectrum mean and variance data collected during aircraft storm penetration periods are also presented. These data show the Doppler spectrum variance to be poorly correlated with gradients of the radial wind, suggesting turbulence is the dominant contributor to Doppler spectrum variance. The data show that areas of moderate to heavy turbulence are distributed throughout the storms. Estimations of turbulence severity are obtained through structure function and Doppler spectrum variance methods. Qualitative results suggest that for observations taken at moderate to long range, storm structure wind shear can strongly bias structure function estimates of turbulence severity, but generally have little influence on estimates from variance methods. The effective turbulence outer scale, the maximum eddy size when the turbulence field is represented by the Kolmogorov inertial subrange law, is typically less than 2 km.