Accession Number:

ADA160380

Title:

In-Flight Turbulence Detection.

Descriptive Note:

Final scientific rept. 10 Oct 83-30 Sep 84,

Corporate Author:

AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Personal Author(s):

Report Date:

1985-03-08

Pagination or Media Count:

61.0

Abstract:

A limited set of radar and aircraft data acquired during the 1981 and 1982 Joint Agency Turbulence Experiment are used to compare incoherent and coherent radar methods for atmospheric turbulence severity estimation. Time series of ground-based radar in-phase and quadrature signal return data are processed by Doppler Fast fourier tranform and incoherent R-meter with and without noise correction methods to determine Doppler spectrum variance. These variance data serve as input to a turbulence algorithm to derive estimates of turbulence severity. Theses estimates are then compared with in-situ aircraft measurements. Results show the order of preference for the radar methods is Dopple, R-meter with noise correction, and R-meter without noise correction. The Doppler, R-meter with noise correction, and R-meter without noise correction. The R-meter without noise correction method must be considered unreliable since it results in large overestimates of turbulence severity when the signal to noise ratio is less than about 12 dB. The R-meter with noise correction, and R-meter with noise correction method generally duplicates well the results derived from Doppler analysis and may be considered a reasonable alternative when Doppler capability is not available. Keywords Incoherent radar Doppler radar R-meter Turbulence severity Eddy dissipation rate Composite severity class.

Subject Categories:

  • Meteorology
  • Active and Passive Radar Detection and Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE