Long-term Variations of Wind Regime in the Free Atmosphere over the European Territory of Russia

A. V. Khokhlova and A. A. Timofeev

The time series of seasonal average values and standard deviations of wind speed components at the isobaric surfaces of 850 and 200 hPa are analyzed on the basis of the data of upper-air observations carried out in 1961–2003 at 18 stations of the Russian Federation territory. The energy spectra of wind speed components in the first and in the second halves of the whole period under study are compared. On the whole, an increase in average values of U-component and decrease in average values of V-component took place both in upper and lower troposphere, and the largest variations occurred in winter season in the upper troposphere. Average coefficients of linear trends of average winter values for the whole region amount to 0.57 and –0.62 m/s per 10 years for the wind components U and V at the isobaric surface of 200 hPa, respectively. The increase in the standard deviations of both components was registered in the upper troposphere in winter period almost on the whole territory. The average coefficients of linear trends of standard deviations at the isobaric surface of 200 hPa in winter for the whole region amount to 0.53 and 0.61 m/s per 10 years for U- and V-components, respectively. The intensity of the annual cycle and processes of intraseasonal scale both in the lower and upper troposphere increased in the second half of the whole interval under study.