Aerosol scattering coefficient fluctuations under stable temperature stratification conditions in the atmospheric surface layer
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Data of in situ observations obtained in Zarechnyi Polygon of the Institute of Atmospheric Optics near Tomsk in the morning on October 9 1996, are analyzed. Ultrasound acoustic meteorological station was capable of recording with a frequency of 2 Hz three components of the wind velocity and temperature of the air, and a two-angle nephelometer of an open type measured the coefficients of scattering at angles of 45 degree(s) and 165 degree(s). Measurements have been carried out continuously for a long time at a sampling frequency of 2 Hz. Devices were mounted on the mast of 5 m height. When stratification was temperature stable, the quasi-periodic vibrations of meteorological parameters and parameters of aerosol scattering was temperature stable, the quasi- periodic vibrations of meteorological parameters and parameters of aerosol scattering were observed with a period of 25 minutes. The oscillations of the transformation coefficient of scattering phase function as well as of temperature were particularly pronounced. The view of time realizations pointed to the presence in the atmosphere of the known as buoyancy waves or gravity waves. The spectra of fluctuations of parameters were calculated. It is noted that spectra of speed, temperature and aerosol concentration, calculated from 17 minute intervals, in the low-frequency region of the inertial interval had greater slope in frequency region from 0.03 Hz to 0.2...0.3 Hz than the slope of the Kolmogorov spectrum (the -5/3 law). Simultaneously, analogous spectrum for vertical component of the wind velocity had the slope close to the Kolmogorov spectrum in the frequency range from 0.03 Hz to 1 Hz.