REMOTE SENSING OF THE TURBULENT CHARACTERISTICS IN THE ATMOSPHERIC BOUNDARY LAYER BY ACOUSTIC RADAR

The magnitude of temperature fluctuation spectrum ΦT(K0) or temperature structure coefficient CT2 can be directly measured by acoustic radar. In atmosphere, the spectrum scale is very wide, so in atmospheric boundary layer the magnitude ΦT(K0) or CT2 measured by acoustic radar is a random variable obeying the logarithmic normal distribution.We analysed the frequency spectra of ΦT(K0) and found that in the frequency range of 10-3-3×10-3 c/s there is a maximum value of vange energy. Between the maximum value range and high-frequency range exists a sharp transitional band of energy. At past years some meteorologists usually considered that there is a gap in the meso-scale range of spectra. In this articale, it is shown that at meso-scale range, whenever in stable or unstable conditions there is a cyclic activity of time scale from several minites to more ten minites and it makes a great contribution to the energy. This phenomena may be of imimportance for the theoritical research of the atmospheric turbulence. Since in the atmosphere the spectral range is very wide, we must select correctly the length of mean time in the measurement of meteorological elements or other physical parameters to obtain their stable means.