Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.

In Figure 2 nacreous clouds which have appeared on 19 January are represented. Clouds of this type possess rich playing iridescent coloring. On appearance, they have some similarity with irisation of high cirri, which are formed at lower heights - below 13.5 km. Observations o fpolar stratospheric clouds over Murmansk in January-February 2010 Fig. 1. Nacreous clouds above Murmansk on 11 January 2010 Fig. 2. The same, that in Figure 1, but on 19 January 2010 The polar stratospheric clouds which have been found out in the stratosphere on 8 and 10 February 2010, under the form and coloring were similar to clouds in January (Fig. 3). However, average heights of the lower border o f the cloud field were lower by 5 km and were 15-20 km. Duration o f registration of these clouds was by 2 hours more, i.e. about 6 hours. Clouds were observed at not only sunrise and sunset but also when the Sun was above the line of horizon. ippli f§i^ Fig. 3. The same, that in Figure 1, but on 8 and 10 February 2010. 191