Measured Spectral Extent of L- and X-Band Radar Reflections from Wind-Blown Trees

摘要

Measurements of the spectral content of L- and X- band radar reflections from several resolution cells containing wind-blown trees are examined under a wide variety of typical wind conditions. Most of the discernible energy (i.e., within 60 dB of the peak zero-Doppler level) occurs in the spectra at Doppler velocities usually less than 1.0 m/s, or at most 2.0 m/s on very windy days. The rates of decay of energy with increasing Doppler velocity in the tails of the spectral distributions at spectral off-sets well removed from zero often appear to be approximately exponential. Estimates of rates of exponential decay in the spectral tails as a function of windspeed are provided in three regimes of windspeed. (Author)