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Kazimirovsky, E. S.

Publications and source records attributed to Kazimirovsky, E. S..

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Lower thermosphere (80-100 km) dynamics response to solar and geomagnetic activity: Overview

The variations of solar and geomagnetic activity may affect the thermosphere circulation via plasma heating and electric fields, especially at high latitudes. The possibility exists that the energy involved in auroral and magnetic storms can produce significant changes of mesosphere and lower thermosphere wind systems. A study of global radar measurements of winds at 80 to 100 km region revealed the short term effects (correlation between wind field and geomagnetic storms) and long term variations over a solar cycle. It seems likely that the correlation results from a modification of planetary waves and tides propagated from below, thus altering the dynamical regime of the thermosphere. Sometimes the long term behavior points rather to a climatic variation with the internal atmospheric cause than to a direct solar control.

Kazimirovsky, E. S.↗
NASA NTRS1989

Effects from the coupling from below on the lower thermosphere dynamics

Results of wind measurements at the midlatitude ionospheric D region are presented. The wind regime of the lower thermosphere is rather sensitive to stratospheric temperature variations, especially to sudden stratospheric warmings. The longitudinal effect in D region dynamics was revealed on the basis of simultaneous wind measurements at some points located practically at the same latitude but in different climatic regions. The distance differences are observed in the statistical distributions of wind parameters, during winter the average zonal wind speed over East Siberia was about twice that over Central Europe, and the semidiurnal zonal tide is weaker over East Siberia. The data on the seasonal reconstruction of circulation and the response of the D region wind field to the stratospheric warmings depend on the intensity and locations of stratospheric disturbances in relation to the observatory. These experimental facts are interpreted as a meteorological control of the D region and as a dependence of the lower thermosphere dynamics on the conditions of dissipation of internal waves propagating from the troposphere and stratosphere.

Kazimirovsky, E. S.↗
NASA NTRS1989

The Soviet contributions towards MAP/WINE

In the winter of 1983 to 1984, the research institutes of the Soviet Union took an active part in the accomplishment of the project Winter in Northern Europe (MAP/WINE) of the Middle Atmosphere Program. Different methods were used to measure temperature, direction and velocity of wind, turbulence, electron concentration in the lower ionosphere, and radio wave absorption. The study of the stratopheric warmings and the related changes in the mesosphere and lower ionosphere was considered of special importance. The analysis of the obtained data has shown, in particular, that during the stratospheric warmings the western wind in winter time becomes weaker and even reverses. At the same time period the electron concentration and the radio wave absorption in the lower ionosphere are often reduced. It is also observed that the high absorption zones move from west to east. These results confirm the concept about the role of the cyclonic circumpolar vortex in the transport of the auroral air to temperate latitudes and about the appearance of conditions for the winter anomalous radio wave absorption.

Rapoport, Z. TA.↗
NASA NTRS1989

The geomagnetic control of the lower thermosphere wind system over East Siberia

The geomagnetic control of ionospheric D region dynamics was revealed and confirmed on the basis of radiophysical wind measurements (1978 to 1983) over East Siberia. The monthly mean parameters of the wind system are different for quiet and disturbed conditions. There is an increase in stability of the meridional wind with increasing level of geomagnetic activity. The influence of geomagnetic storms on the measured wind is considered on the basis of 31 events. There are effects on the phase of the semidiurnal tidal wind, but variations of amplitude are weak. The effect of the geomagnetic storm depends on the intensity and is more clear-cut for the A sub p is greater than 100.

Kazimirovsky, E. S.↗
NASA NTRS1989

Midlatitude seasonal behavior of tides near the mesopause level

Wind measurements near the mesopause level were provided in Badary (Eastern Siberia, USSR) by the D1 method using a low frequency (200 kHz) radio transmitter during 1976 to 1986. The seasonal variations of wind level are analyzed and compared with other midlatitude wind measurements and with some theoretical preditions. It is shown that tidal parameters depend not only on latitude but on the longitude as well. The annual variation of diurnal and semidurnal tide (zonal and meridional) have maxima in summer and minima in winter. There are significant differences between annual variations of phases for diurnal and semidiurnal tides. These differences are especially distinct for summer and autumn. There is no systematic seasonal variation of the phase of the semidiurnal tide (average value similar to 6 hours).

Kazimirovsky, E. S.↗
NASA NTRS1984

The Dynamics of Ionospheric D Region over East Siberia

Some main results of experimental investigations of the dynamical regime of the ionospheric D-region over East Siberia are presented. Regular measurements of horizontal ionospheric drifts by the radio method of closely spaced receivers, using a long wavelength transmitter operating at a frequency of 200 kHz, were carried out near Irkutsk, USSR, since 1975. The seasonal and inter-annual variations of prevailing wind (zonal and meridional), and amplitudes and phases of semi-diurnal tides are investigated. Evidence is presented to show the response of D-region dynamics to stratospheric warmings. Planetary and gravity waves are found in the wind field. Comparison with results of analogous measurements in Central Europe (Collm, GDR) reveals a longitudinal effect on the dynamical regime of the mid-latitude lower thermosphere.

Kazimirovsky, E. S.↗