Andrey Medvedev

Calibration methods for absolute measurements at the Irkutsk incoherent scatter radar

The Irkutsk Incoherent Scatter Radar (IISR) has a frequency band of 154–162 MHz and a polarization filter which allows measurements of electron density profiles using fadings in a received signal that arise due to the Faraday rotation of radio waves in the ionosphere. In addition, profiles of electron and ion temperatures can be obtained by examination of a signal autocorrelation function. There is a radar equation that links those plasma parameters with the power of the received incoherent scatter signal. This paper dedicated to the receiver channel calibration that is necessary for absolute measurements of the power. Absolute measurements provide us with an additional method of data processing and may reveal signal sources that have a coherent nature. We apply the calibration method based on sky noise maps, where we use the simulated antenna temperature as a source of known signal.

Some peculiarities in the ionosphere dynamics near the ionization maximum from Irkutsk incoherent scatter radar data for low and moderate solar activities

Аннотация. Работа посвящена морфологическому исследованию поведения электронной концентрации в ионосфере на высотах 200–400 км на основе непрерывных серий наблюдений в 2007– 2014 гг. на Иркутском радаре некогерентного рассеяния. Представлены суточно-высотные вариации усредненной электронной концентрации для всех сезонов (зима, весна, лето, осень) и двух уровней солнечной активности (низкой и умеренной). Выполнены сравнения наших результатов с результатами аналогичных исследований на таких радарах некогерентного рассеяния, как Миллстоун-Хилл, Аресибо, EISCAT, ESR, AMISR. Проведен анализ суточных вариаций электронного содержания для двух диапазонов высот: 180–250 и 250–600 км, полученных по данным Иркутского радара некогерентного рассеяния и ионозонда.

Path-Dependent Development of Mass Housing in Moscow, Russia

Since the 1950s, Moscow’s housing development has been underlined by modernist planning schemes. From the 20th to 21st centuries, the quality and appearance of apartment buildings changed, but housing estates designed as coherent neighbourhoods not only remain the principal type of housing organization but are still being constructed in Moscow and its suburbs. Though the concept itself has not been challenged by policy-makers and planners, by the end of the 20th century it became apparent that early housing estates have become a problem due to poor quality of construction. In 2017, the Moscow Government announced a highly controversial program suggesting the demolition of housing estates built between the 1950s and 1960s. Our contribution analyzes the history of housing estates development in Moscow aiming to understand what has led to the adoption of the 2017 “renovation” program. If this program ends up being fully implemented, along with planned renovation of former industrial areas, the cityscape of Russia’s capital will be completely redefined.

Development of the technique for determination of plasma temperatures subject to Faraday effect for Irkutsk incoherent scatter radar

The problem of correct ion and electron temperatures yielded on Irkutsk Incoherent Scatter Radar (IISR) is actually prominent. The existing algorithms of temperatures reconstruction on the IISR data counts out some constructive peculiarities of the radar, what can lead to increase of systematic errors. The obtained height and time profiles of ion temperatures do not suffice the ones expected on the basis of comprehensive concepts and experimental data of other facilities (e.g. Millstone Hill Incoherent Scatter Radar). The Faraday Effect on height power profile of the backscattered signal is assumed to be the key factor of this discrepancy. Allowance for this effect results in considerable complication of the inverse problem. In the present paper, the technique for systematic error estimation and correction based on direct model of backscattered signal was proposed.

Interferometric observation of Cygnus-А discrete radiosource scintillations at Irkutsk Incoherent Scatter radar

We propose a new method for analyzing data from the Irkutsk Incoherent Scatter Radar. The method allows us to accomplish interferometric observation of discrete cosmic radio source characteristics. In this study, we analyze ionospheric scintillations of the radio source Cygnus-A. Observations were made in 2013 during regular radar sessions within 5–15 days for different seasons; the effective time of observation was 15–30 minutes per day. For interferometric analysis, the properties of correlation (coherence) coefficient of two independent recording channels were used. The statistical analysis of data from the independent channels allows us to construct two-dimensional histograms of radio source brightness distribution with a period of 18 s and to determine parameters (the maximum position and the histogram width) representing position and angular size of the radio source for each histogram. It is shown that the change of statistical characteristics does not correlate with fluctuations in power (scintillations) of the signal induced by radio wave propagation through ionospheric irregularities.

Calculation of meridional neutral winds in middle latitudes from the Irkutsk incoherent scatter radar data

А.А. Щербаков Институт солнечно-земной физики СО РАН, Иркутск, Россия, scherbakov@iszf.irk.ru А.В. Медведев Институт солнечно-земной физики СО РАН, Иркутск, Россия, medvedev@iszf.irk.ru Д.С. Кушнарев Институт солнечно-земной физики СО РАН, Иркутск, Россия, ds_k@iszf.irk.ru М.В. Толстиков Институт солнечно-земной физики СО РАН, Иркутск, Россия, maxim@iszf.irk.ru С.С. Алсаткин Институт солнечно-земной физики СО РАН, Иркутск, Россия, alss@iszf.irk.ru A.A. Shcherbakov Institute of Solar-Terrestrial Physics, Irkutsk, Russia, scherbakov@iszf.irk.ru A.V. Medvedev Institute of Solar-Terrestrial Physics, Irkutsk, Russia, medvedev@iszf.irk.ru D.S. Kushnarev Institute of Solar-Terrestrial Physics, Irkutsk, Russia, ds_k@iszf.irk.ru M.V. Tolstikov Institute of Solar-Terrestrial Physics, Irkutsk, Russia, maxim@iszf.irk.ru S.S. Alsatkin Institute of Solar-Terrestrial Physics, Irkutsk, Russia, alss@iszf.irk.ru