A.S.Besprozvannaya, G.I.Ohl, T.I.Schuka, O.A.Troshichev (Arctic and Antarctic Research Institute, St.Petersburg)

B.I.Sazonov, I.A.Scherba (The Main Geophysical Observatory, St.Petersburg)

Sazonov index characterizing the intensity of meridional circulation has been used to study the influence of short-term changes in solar activity on baric field perturbations in the stratosphere. The results show that stratospheric circulation responses to various manifestation of solar activity in different manner. The solar central meridian passage of active regions leads to development of stratospheric perturbations in case of both west and east QBO phases. The Forbush decrease of galactic cosmic rays is followed by fall of the stratospheric perturbation to minimal level irrespective QBO phase. The interplanetary sector boundaries intersection of Earth leads to increase of the stratospheric perturbation in case of away/toward boundary and to decrease of the perturbation in case of toward/away boundary, the effect being dependent on content of volcanic aerosols in the stratosphere and QBO phase. The results testify in favour of action of global electric chain mechanism put forward by Tinsley et al.[1989].

Y. Kulikov (Polar Geophysical Institute, 183010, Murmansk)

A theoretical model for the simulation of rocket-borne observations of the IR radiation of ozone in the fundamental vibrational-rotational 9.6 mkm band in the upper atmosphere has been developed. A distinctive feature of the model is that it takes into account chemical interaction and vertical mass transport of the minor constituents of the odd oxygen and odd hydrogen "families". Along with the flux of the IR radiation of ozone in the 9.6 mkm band the model also allows to calculate the height profiles of the O3, O(3P), O(1D), H, OH, and HO2 number densities and the vertical eddy diffusion coefficient in the height range 70 to 110 km for the actual geophysical conditions of rocket experiments. Sample simulation results including the minor constituents number density height profiles and zenith radiation fluxes in the ozone 9.6 mkm band are presented to illustrate the effects of variability of some basic geophysical parameters characteristic of the night time polar winter upper atmosphere.

V.C. Roldugin, A.V. Roldugin, G.V. Starkov (Polar Geophysical Institute)

In January 1996 observations of Polar Stratospheric Clouds (PSC) have been carried out in Lovozero (67^O59’N, 35^O05’E ). Visual examination, TV record and photography by an amateur camera on coloured film were used as observant methods. The identification of PSC is determined on Sun elevation angle below -5^O during dawns and twilights. PSCs have been observed 4 times from 11 cases of good weather conditions. During all 4 events their motion has the southeastward direction. Size, common area, and altitude differ one another too much for the events.

Y. Kulikov (Polar Geophysical Institute, 183010, Murmansk)

For a number of rocket measurements of the 9.6 mkm emission of ozone carried out at various levels of auroral activity in the night time polar upper atmosphere the altitude distributions of the odd oxygen and odd hydrogen constituents number densities and vertical eddy diffusion coefficient estimates in the altitude range 70 to 110 km have been derived on the basis of a specially developed computer simulation technique. It has turned out that in the undisturbed upper polar atmosphere there is practically no turbulence. In case of auroral activity there is enhancement of turbulence in the turbopause region. However, estimated typical values of the vertical eddy diffusivity for disturbed conditions are 104 to 105 cm2/s, that is one or two orders of magnitude less than are the average widely accepted values for the turbopause region. The derived values of the vertical eddy diffusivity indicate the need for a thorough revision of the conventional ideas about dynamics and intensity of turbulence in the upper atmosphere.

V.C. Roldugin (Polar Geophysical Institute, Academy, Apatity, Murmansk reg., Russia)

Kjell Henriksen (The Auroral Observatory, University of Tromso, 9037 Tromso, Norway)

The wave-like character of the total ozone variations is revealed at Aral Sea and Karaganda in Middle Asia, and at Tromso and Murmansk in the Arctic. The waves have periods 10-20 days and amplitude about 20-30 DU. They appear practically every year, accordingly data for 21 years when the ozone data did not contain too much gaps. During a year the periods in both regions coincide. By crosscorrelation analysis their movement was determined as eastward on both pairs of stations with the velocity of 11^O/day. For one year it was possible to determine the zonal wave number which was equal 2, and the eastward motions coincide with the general motion of tropospheric weather pattern.

Ludmila N.Makarova, Alexander V.Shirochkov, Julia A.Grigor'eva

The variations of the thermal regime in the high-latitudinal middle atmosphere have been studied by means of analyzing the data of the rocket soundings at Heiss Island in period of 1984 - 1990. The real vertical temperature profiles were compared with correspondent model data, calculated from the MSIS-90 model. The deviations magnitudes of the experimental temperature values from the model ones were analyzed in their dependence on the solar wind conditions as well as on the geophysical situation in whole referred to an observation moment. It is possible to derive the following conclusions from this investigation.

1. The solar wind kinetic pressure does influence the thermal regime of the middle atmosphere at high- latitude. The electric fields in the magnetosphere and ionosphere produced by the excessive kinetic pressure of the solar wind are the most probable cause of this phenomenon.

2. Energetic contribution of the solar wind to the thermal balance of the middle atmosphere at high latitudes during wintertime of the minimum solar activity years is comparable with correspondent contribution provided by the Sun UV radiation.

3. There are strong reasons to believe that physical nature of the Quasi-Biennial Oscillations (QBO) phenomena is determined by the solar wind kinetic pressure variations.

Valentin C. Roldugin (Polar Geophysical Institute, Academy, Apatity, Murmansk reg., Russia)

Kjell Henriksen (The Auroral Observatory, University of Tromso, 9037 Tromso, Norway)

One of the peculiarities of the global circulation is the polar vortex which appears during winters at about 70^O . It does not permit to the ozone rich air from the middle latitudes to reach the high latitudes. Some changes of the global wind circulation must be reflected in ozone changes at high latitudes. Manney et al. [1994] have investigated a position and value of the Arctic vortex during 16 winters, from 1978-79 till 1993-94. They calculated area integrals of potential vorticity (PV) on the 465^OK isentropic surface for the time interval from 1 December through 29 April. It is seen on those pictures that during this 16 years period the vortex intensifies in general more and shifts to the south.

It is interesting to compare vortex changes with the total ozone variations at high latitude stations. Manney et al. [1994] have presented the average PV gradient for each winter as a simple scalar characteristic of the vortex. We have used the total ozone data of Arctic stations Tromso (69.6^ON, 19.0^OE ) and Murmansk (69.0^ON, 33.0^OE) for these years. Here maxima in ozone occur in April as a rule. Before April the southerly wind brings the ozone, after April there is no the ozone transport. The April ozone value shows how much of ozone was brought during winter - spring. So the comparison of the was made for April. In Tromso we have only 8 Aprils during 1985-1992 years, in Murmansk - 14 for the period of 1979-1992. The comparison was made both in time-dependence form and in correlation field form. Very good negative correlation is found visually on both stations, the correlation coefficient is equal to -0.92 in Tromso and -0.88 in Murmansk. Such comparison was made also for Reykjavik (64.1^ON, 21.9^OW ). The correlation is small and uncertain here, and the sign of correlation is positive, i.e. a power Arctic vortex increases the ozone content at this station.

We connect the ozone decrease in last years with the replacement and strengthening of the polar vortex. The global ozone changes were investigated by Bojkov and Fioletov [1995]. As it is seen from their article, a significant ozone decrease occurs only in high latitudes 65-90^O, and in the latitudinal belt 35^ON - 35^OS really there is no any decrease. So the physics of the ozone decrease may be a change of the pattern of global air circulation, in the first place the polar vortex displacement.