Abstract.We describe the Fabry-Perot interferometer designed to study Earth's upper atmosphere. We propose a modification of the existing data processing method for determining the Doppler shift and Doppler widening and also for separating the observed line intensity and the background intensity. The temperature and wind velocity derived from these parameters are compared with physical characteristics obtained from modeling (NRLMSISE-00, HWM14). We demonstrate that the temperature is determined from the oxygen 630 nm line irrespective of the hydroxyl signal existing in interference patterns. We show that the interferometer can obtain temperature from the oxygen 557.7 nm line in case of additional calibration of the device. The observed wind velocity mainly agrees with model data. Night variations in the red and green oxygen lines quite well coincide with those in intensities obtained by devices installed nearby the interferometer.
We analyze the results of a rare long-lived quasisymmetric ellipsoidal-annular meteor trail recorded on November 18, 2017 by two optical all-sky cameras, spaced at a distance of 150 km. The analysis is based on astrometric processing results with the use of baseline measurement methods. We determine spatial-kinematic characteristics of the meteor trail, and find features of its evolution. The ignition and extinction heights of the meteor were in the range 75–120 km. The estimate of the meteor brightness gives the absolute magnitude value of about –7.3m. It is shown that the distribution of all parts of the long-lived meteor trail occurs in the same plane at a height of ~90 km at a speed of ~320 m/s and, apparently, cannot be a consequence of an air mass movement. The total time of the meteor trail observation was more than 30 min. We offer possible explanations for the results obtained in the context of upper atmosphere processes.
Using vertical sounding data obtained by the Irkutsk digisonde DPS-4 from 2003 to 2016, we have studied the frequency of occurrence of the F1 layer in winter conditions. The frequency of occurrence of the F1 layer in December–January is shown to be more than twice lower than that in February at any level of magnetic activity. At moderate and low solar activity under quiet geomagnetic conditions, the appearance of F1 layer in midlatitudes of the Northern Hemisphere may be caused by active thermodynamic processes, which lead to transformation or destruction of the circumpolar vortex at heights of the middle atmosphere. Such global dynamic changes occurring in the winter strato-mesosphere are often associated with sudden stratospheric warming events, which are accompanied by increased generation of atmospheric waves of various scales. These wave disturbances can propagate upward to the heights of the lower thermosphere and ionosphere, carrying a significant vertical flow of energy and causing variations in the composition, thermodynamic parameters of the neutral atmosphere and ionosphere.
Институт солнечно-земной физики СО РАН, Иркутск, Россия, mikhalev@iszf.irk.ru А.Б. БелецкийИнститут солнечно-земной физики СО РАН, Иркутск, Россия, beletsky@iszf.irk.ru Р.В. ВасильевИнститут солнечно-земной физики СО РАН, Иркутск, Россия, roman_vasilyev@iszf.irk.ru Г.А. ЖеребцовИнститут солнечно-земной физики СО РАН, Иркутск, Россия, gaz@iszf.irk.ru С.В. ПодлесныйИнститут солнечно-земной физики СО РАН, Иркутск, Россия, step8907@mail.ru М.А. ТащилинИнститут солнечно-земной физики СО РАН, Иркутск, Россия, miketash@iszf.irk.ru М.Ф. АртамоновИнститут солнечно-земной физики СО РАН, Иркутск, Россия, artamonov.maksim@iszf.irk.ru Аннотация. Исследована пространственновременная динамика среднеширотного сияния по данным наблюдений на юге Восточной Сибири в ходе большой геомагнитной бури Святого Патрика 17 марта 2015 г. Выполнен морфологический анализ характеристик наблюдаемого сияния. Сделан предварительный вывод, что анализируемое событие является результатом проявления двух форм среднеширотных сияний (тип «d» и SAR-дуга) и обычного полярного сияния, наблюдавшегося у северного горизонта. Максимальная интенсивность доминирующей эмиссии [OI] 630.0 нм (~14 кРл) позволяет отнести данное среднеширотное сияние к экстремальным сияниям, наблюдавшимся в средних широтах, которое уступает лишь сиянию во время супербури 20 ноября 2003 г. (~19 кРл).Ключевые слова: геомагнитная буря, среднеширотное сияние, спектры среднеширотного сияния, авроральные эмиссии 557.7 и 630.0 нм. Abstract.We study the spatiotemporal dynamics of mid-latitude aurora from observations in the south of Eastern Siberia during St. Patrick's severe geomagnetic storm on March 17, 2015. We perform a morphological analysis of characteristics of the observed auroras. A preliminary conclusion is drawn that the analyzed event is the result of the manifestation of mid-latitude auroras of two types (type "d" and SAR arc) and ordinary aurora observed at the northern horizon. The maximum intensity of the dominant emission [OI] at 630.0 nm (~14 kR) allows this mid-latitude aurora to be attributed to the extreme auroras occurring in midlatitudes, which is second only to the November 20, 2003 superstorm (~19 kR).Keywords: geomagnetic storm, mid-latitude aurora, spectrum of mid-latitude aurora, 557.7 and 630.0 nm emissions.A.V. Mikhalev, A.B. Beletsky, R.V. Vasilyev, G.A. Zherebtsov, С.В. Подлесный, М.А. Тащилин, М.Ф. Артамонов S.V. Podlesny, M.A. Tashchilin, M.F. Artamonov
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