Effect of Finite Radar Pulse Volume on Turbulence Measurements.
Technical rept. Aug 71-Jul 72,
CHICAGO UNIV ILL LAB FOR ATMOSPHERIC PROBING
Pagination or Media Count:
Equations relating the mean of the Doppler spectrum and the distribution of point velocities, and their spectra are derived under the assumptions that 1 the scatterers follow the air motion faithfully, 2 the reflectivity is constant, and 3 the beam illumination function is separable. Relationships between the 1-D longitudinal and transverse spectra of the mean velocity and the 3-D spectrum of the point velocities are derived. Numerical computations with a model Kolmogorov-Obukhov turbulence spectrum are performed to illustrate the effects of filtering. The ratio of the total energy under measured spectrum to that under spectrum of point velocities is computed as a function of beam dimensions. An equivalent rectangular filter approximation is proposed for computing the 1-D spectra. Analytical results are obtained for longitudinal spectrum and are shown to be in excellent agreement with numerical results for actual filter.
- Atmospheric Physics