SPECTRAL DENSITIES OF SURFACE ATMOSPHERIC METEOROLOGICAL ELEMENTS IN A WIDE FREQUENCY RANGE

V. N. Ivanov and A. V. Khokhlova

Statistical estimates of the temporal variability of meteorological parameters in the range from several years to several seconds are obtained on the basis of spectral analysis of surface pressure, temperature, and wind speed time series for the Moscow region. Temperature and pressure spectra show that periods of maximum temporal variability fall in the range of 5 ∙ 10-7 —1 ∙ 10-6 s-1 (20 and 10 days, respectively). The decrease in spectrum with frequency growth from 5 ∙ 10-6 s-1 to 0.1 s-1 follows a power law with exponent —2. Besides annual and diurnal harmonics, the temperature and pressure spectra display harmonic components with periods from several years to several hours. The relative annual maximum in the temperature spectrum is more than an order of magnitude greater than the diurnal one, which, in turn, is twice as large as a 10—20 day maximum. The biennial maximum is two orders of magnitude less than the annual one. Of particular interest are 21- and 41-day components in pressure time series. Unlike temperature and pressure spectra, the wind velocity spectra have a maximum at (2—3)∙10-6 s-1 frequencies (4—5-day periods), with a mesometeorological minimum. The spectra of the modulus of wind velocity and its components have some considerable differences: the synoptic range of variability is much greater in the zonal and meridional components than in the velocity modulus.