Physics of auroral phenomena : proceedings of the 40th annual seminar, Apatity, 13-17 March, 2017 / [ed. board: N. V. Semenova, A. G. Yahnin]. - Апатиты : Издательство Кольского научного центра РАН, 2017. - 143 с. : ил., табл.

V.C. Roldugin et al. Discussion Advantage of photographic data is simplicity of detection of wavy structures and irregularities in NLCs. In our case on 12 August 2016 waves and thin structures of NLCs took place practically all the time, as examples see Fig. 1 and 4. The absence of PMSE and increase in the signal amplitude of the radar during NLCs can be explained with uniformity of NLCs within the directional pattern: for appearance of radio reflection heterogeneity o f electron concentration or density of the charged aerosols are necessary. Increasing of the reflected ordinary wave amplitude could be caused by appearance over the radar irregularities of reflected structures. The reflections could have not partial reflection nature but poor radar reflections caused by structures of NLCs. The structures could be created by acoustic waves with periods less 5 minutes during acoustic compression and rarefaction effects. Gravity waves have the feature of buoyancy and only move the atmosphere layers without sufficient changing of their properties. In this case received reflection is at low level. Vertical movements of PMSE also can be connected with irregularities. About the movements it is often mentioned in literature but values of speeds are given seldom. Vlaskov and Bogolyubov [1998] tell about 0.3 m/s, [Roldugin et. a l, 2000] according to EISCAT data specify 0.14 - 0.83 m/s, Roldugin et al. [2001] give the value in 1000 times more - 30 m/s. In the work the vertical speed of 0.5 m/s and 1.3 m/s are given. Vertical movements can have two reasons: passing of gravitational waves through a layer, or falling of aerosols or meteor dust. Big speeds in work [Roldugin et al., 2001] are obviously connected not with aerosols, but with the areas of turbulence. In the considered case the night peak of activity of the meteor shower Perseid was observed at 12-13 August 2016. The formula for the speed of falling of the meteoric dust surrounded by the ice cover was offered in [Roldugin et. al., 2000], and assessment by it gives the size of 0.2 m/s. The dispersion from 0.14 to 1.3 m/s can be caused by different parameters of meteor dust and/or the size of aerosols. We think that the reason of uncertainty of interpretations of connection o f NLCs and PMSE is obscurity of the nature and dynamics of the particles responsible for both phenomena. Summary On 12 August 2016 over the Tumanny observatory the all sky camera of the Lovozero observatory observed NLCs. Presence of NLCs over the partial reflection facility has caused increase in amplitudes of ordinary and unusual waves at the heights o f 82-87 km. In photos of NLCs of the all sky camera the wave structure of clouds was clearly seen. The similar wave structure was visible also in behavior of amplitudes of the reflected ordinary wave. We connect change of amplitude of the reflected signal with passing of NLCs over the partial reflection facility. Heterogeneity of NLCs within the antenna directional pattern which was caused by both acoustic and acoustic-gravity waves, and thin structures of NLCs were necessary for appearance of radio reflection. The reason o f the observed vertical movements down with speeds of 0.5 m/s and 1.3 m/s is falling of the ice aerosols formed around particles of meteoric dust. Joint observation of the all sky camera and the partial reflection facility give possibility to estimate heights and thickness of NLCs and also periodic structure of NLCs. References Knizova, P. K., Mosna Z. Acoustic-Gravity Waves in the ionosphere During Solar Eclipse Events // Acoustic Waves - From Microdevices to Helioseismology / Ed. by Prof. Marco G. Beghi. P. 303-320. InTech. 652 p. 2001. Roldugin V.C., Kirkwood S., Maltsev Yu. P., Galakhov A.A. EISCAT radar reflection from the vicinity of a noctilucent cloud // Phys. and Chem. of Earth, part В. V. 25. N. 5-6. P. 507-509. 2000. Roldugin W.C., Tereshchenko V.D., Vasiljev Ye.B., Kirkwood S. Observations by partial reflection radar during noctilucent cloud appearance // Physics of auroral phenomena. Proceedings of the ХХШAnnual Seminar. Apatity. P. 86-89. 2001. Stebel K., Barabash V., Kirkwood S., Siebert J., Fricke K. Polar mesosphere summer echoes and noctilucent clouds: Simultaneous and common-volume observations by radar, lidar and CCD camera // Geophys. Res. Lett. V. 27. P. 661-664. 2000. Tereshchenko V.D., Vasiljev E.B., OvchinnikovN.A., Popov A.A. Mediumwave radar of Polar Geophysical Institute for research of the lower ionosphere. Technical equipment and techniques of geophysical experiment. Apatity: KSC RAS, PGI. P. 37-46. 2003. (in Russian) Vlaskov V.A., Bogolyubov A.A. Observation ofPolar Mesospheric Summer Echoes with partial reflection radar // Bulletin MSTU. V. 1(2). P. 3-22. 1998. (in Russian) appearance in the spectrum o f the reflected signal of the acoustic wave periods (less 5 minutes). / - ' w v 21.5 22 22.5 23 23.5 24 UT, час Figure 7. Amplitude of the reflected ordinary wave (above) and its wavelet-spectrum (below). 115