CROSS-SPECTRA OF VERTICAL WIND VELOCITY AND ECHO-SIGNAL INTENSITY FROM SODAR MEASUREMENTS

Data are presented on the frequency cross-spectra of the vertical component of wind at different altitudes and cross-spectra between echo-signal intensity A2 and vertical wind velocity at the same altitudes, as derived from acoustic sounding of convective atmosphere. Significant coherence between w(z) and A2(z) at the height range in value from 40 to 107 m is found: R(wA2) = 0.5-0.8 at low frequency band 8.10(-4) Hz-2.10(-3) Hz and R(wA2) = 0.3-0.4 at frequency band 5.10(-3) Hz-10(-2) Hz. Vertical coherence for the vertical velocity from sodar data is analyzed in terms of Davenport's model: R(ww)(f, z1, z2) = exp (-a(z)f-DELTA-z/V), where V is the average velocity in the interval DELTA(z). The vertical-decay constant a(z) to be independent from DELTA-z/z at the range in value from 0.16 to 0.83 is found by experiment.