THE MICROWAVE MONITORING OF THE MIDDLE ATMOSPHERE OZONE ON KOLA PENINSULA DURING LAST THREE WINTERS

This work presents long-term investigation of a nature of the middle atmosphere ozone variability using a method ground-based microwave radiometry. Measurements were carried out with the help of mobile microwave ozonemeter (observation frequency 110836.04 MHz) which was established in Polar Geophysical Institute at Apatity (67N, 33E). The parameters of the device allow to measure a spectrum of the emission ozone line for time about 15 min with a precision of ~ 2%. The error of estimating the vertical distribution of ozone on the measured spectra by above described device does not exceed 10-15%. On the measured spectra were appreciated of ozone vertical profiles in the layer of 22 – 60 km which were compared to satellite data MLS/Aura and with the data of ozonesondes at station Sodankyla (67N, 27E). The analysis of the microwave data on behavior of polar mesospheric ozone in past winters shows, that sudden stratospheric warming (SSW) can cause significant and long influence on its diurnal variation which should be determined by photochemical processes.

Variations in mesospheric temperature during polar mesospheric summer echoes.

The behavior of the ordinary radio wave amplitude at the frequency of 2.66 MHz of the partial reflection radar of the Polar Geophysical Institute (Tumanny observatory, Murmansk region, 69.0N, 35.7E) during the appearance of the polar mesospheric summer echoes on August 15, 2015 was considered. Using of radio physical method from the spectra of the amplitude at different heights the mesospheric temperature profile was calculated for the considered data. Significant reductionof temperature values near the heights of the mesopause corresponded to sharp changes in the amplitude spectra of the ordinary wave.

Results of microwave monitoring of middle atmosphereozone in polar latitudes for two winter seasons 2017-2018 and 2018-2019.

We present data continuous series of microwave observations of the middle atmosphere in winters 2017-2018, 2018-2019 and 2019-2020. In each of these winters sudden stratospheric warming were marked.Measurements were carried out with the help of mobile ozonemeter (observation frequency 110836.04 MHz), which was established at Polar Geophysical Institute in Apatity (67N, 33E). The parameters of the device allow to measure a spectrum of the ozone emission line for time about 15 min a precision of 2%. On the measured spectra were appreciated of ozone vertical profiles in the layer of 22 60 km which were compared to satellite data MLS/Aura and with the data of ozonesonde at station Sodankyla (67N, 27E). The microwave data on the behavior of mesospheric ozone (altitude 60 km) indicate the presence of bothphotochemical and dynamic components in its changes.

Estimated nitric oxide density in auroras from ground-based photometric data

In this paper, we numerically estimate the nitric oxide density in auroras, using photometric data on 427.8, 557.7, and 630.0 nm emission intensities. The data were obtained at midnight at observatories of the Polar Geophysical Institute. These estimates were made using a numerical modeling procedure with a time-dependent model of the auroral ionosphere [Dashkevich et al., 2017]. It is shown that the NO density in the maximum of the altitude profile is between (1÷3.3)∙10^8 cm–3. The obtained estimates indicate the absence of a correlation between the [NO]max values and 427.8 nm emission intensities.

Estimated nitric oxide density in auroras from ground-based photometric data

In this paper, we numerically estimate the nitric oxide density in auroras, using photometric data on 427.8, 557.7, and 630.0 nm emission intensities. The data were obtained at midnight at observatories of the Polar Geophysical Institute. These estimates were made using a numerical modeling procedure with a time-dependent model of the auroral ionosphere [Dashkevich et al., 2017]. It is shown that the NO density in the maximum of the altitude profile is between (1÷3.3)∙10^8 cm–3. The obtained estimates indicate the absence of a correlation between the [NO]max values and 427.8 nm emission intensities.

Peculiarities of soft gamma-radiation variations in the atmosphere

Soft gamma-radiation (20-400 keV) arriving from the atmosphere is being monitored by Polar Geophysical Institute (PGI), Apatity, Russia, at several stations located between Spitsbergen and the Causases. In Apatity and Spitsbergen, it has been carried out for ten years already. Detectors of the same type with output integral channels > 20 keV and > 100 keV are used. All the stations record increases in the gammaradiation flux, which are sometimes as high as 100%. These increases occur all the year round, in winter and summer and are recorded at all the stations. A great database on these increases has been used to analyze their characteristics. The detector used in Apatity, is integrated into a complex set carrying out monitoring over the main components of the secondary cosmic rays. According to the earlier experiments, no radioactive contamination has been found in precipitation. The integral and differential data have been analyzed to reveal the peculiarities of the phenomenon studied.

Comparison of Numerical Simulations of the Electron Density in the D-Region Ionosphere with Measurements of the Radar of Partial Reflections

The paper reports results of a comparison of the measured electron density in the ionospheric D-region measured using the partial reflection facility at the observatory. Tumanny of the Polar Geophysical Institute (69.0°N, 35.7°E) with numerical simulations performed using the theoretical model of the Polar Geophysical Institute (PGI) (Murmansk, Russian Federation). The model was examined using experimental data obtained under quiet geomagnetic conditions in March, 2017. The comparative analysis carried out in this study shows a very good agreement of the PGI model with experimental data and indicates that the IRI-2016 model fails to adequately reproduce measurements in regions with high electron density gradients.

Auroras in the cusp and its poleward vicinity: a case study

Summary We present a case study of the dayside aurora observed simultaneously with optical instruments from the ground and with auroral particle spectrometers aboard the DMSP F16 and F17 satellites. Optical observations were carried out with an all-sky camera at the Polar Geophysical Institute (PGI) observatory Barentsburg on Svalbard. The aurora as a whole moved equatorward in response to negative turning of the IMF Bz component and then the distinct faint rayed arc intensified, moved to the north and faded. Satellite DMSP F17 crossed the cusp twenty minutes after Bz turned southward. Joint analysis of optical and satellite data showed that faint auroral structures are embedded into the cusp precipitations and correspond to the bursts of electron precipitations with energy below 100 eV. The next satellite crossed the camera field-of-view ten minutes later and the data showed that the source of the faded poleward moving rayed arc was located, most probably, on the non-closed magnetic field lines. This finding and the presence of ion-energy dispersion in the DMSP data allows us to make the conclusion that the dayside reconnection may be considered as the reason for this kind of aurora activity. In this study we also estimated the altitude and horizontal scale of auroral rays in the cusp.

New narrow-beam neutron spectrometer in complex monitoring system

In the interaction of cosmic rays (CRs) with Earth’s atmosphere, neutrons are formed in a wide range of energies: from thermal (E≈0.025 eV) to ultrarelativistic (E>1 GeV). To detect and study CRs, Polar Geophysical Institute (PGI) uses a complex monitoring system containing detectors of various configurations. The standard neutron monitor (NM) 18-NM-64 is sensitive to neutrons with energies E>50 MeV. The lead-free section of the neutron monitor (BSRM) detects neutrons with energies E≈(0.1÷1) MeV. Also, for sharing with standard detectors, the Apatity NM station has developed and installed a neutron spectrometer with three energy channels and a particle reception angle of 15 degrees. The configuration of the device makes it possible to study the degree of anisotropy of the particle flux from different directions. We have obtained characteristics of the detector (response function and particle reception angle), as well as geometric dimensions through numerical simulation using the GEANT4 toolkit [Agostinelli et al., 2003]. During operation of the device, we collected database of observations and received preliminary results.

New narrow-beam neutron spectrometer in complex monitoring system

In the interaction of cosmic rays (CRs) with Earth’s atmosphere, neutrons are formed in a wide range of energies: from thermal (E≈0.025 eV) to ultrarelativistic (E>1 GeV). To detect and study CRs, Polar Geophysical Institute (PGI) uses a complex monitoring system containing detectors of various configurations. The standard neutron monitor (NM) 18-NM-64 is sensitive to neutrons with energies E>50 MeV. The lead-free section of the neutron monitor (BSRM) detects neutrons with energies E≈(0.1÷1) MeV. Also, for sharing with standard detectors, the Apatity NM station has developed and installed a neutron spectrometer with three energy channels and a particle reception angle of 15 degrees. The configuration of the device makes it possible to study the degree of anisotropy of the particle flux from different directions. We have obtained characteristics of the detector (response function and particle reception angle), as well as geometric dimensions through numerical simulation using the GEANT4 toolkit [Agostinelli et al., 2003]. During operation of the device, we collected database of observations and received preliminary results.