<title>Atmospheric turbulence remote sensing by cw and pulsed CO2 Doppler lidars</title>

Abstract

The theoretical basis for wind velocity field parameters' measurements using CW Doppler Lidars (DL) is outlined. The instant power spectrum of photocurrent is shown to be histogram of velocity projection field with a weight depending on Dl's parameters. A non-destructive long-range method is presented for measuring the structure constant of the wind velocity field. The essence of the method is (the constancy of the backscatter coefficient is assumed): the average square width of the DL photocurrent power spectrum is the averaged structure function of the wind velocity weighted with a function depending on the DL parameters, the measurement time and the average wind velocity. Consequently, it is proportional to velocity structure constant with a factor depending on the DL parameters, the measurement time, the average wind velocity, the internal and external scales of turbulence. At certain DL parameters and measurement time the factor is shown to be practically independent from the average wind velocity, the internal and external scales of turbulence, thus a priori estimate can be successfully used instead of their real values. The differences between structures of CW and pulsed DL signal are discussed. The described above method is applied for pulsed DL.