Seasonal and Daily Variations in the Ion Content of the Earth’s Middle Atmosphere and Ionosphere D. V. Grankin, I. A. Mironova, E. V. Rozanov Bulletin of the Russian Academy of Sciences Physics, 2025 Abstract The high latitude Earth’s atmosphere is ionized via direct solar radiation. This results in the formation of positively charged ions through, e.g., photoionization and the ionization of NO. A one-dimensional chemical and climatic model with interactive neutral and ionic chemistry is used to track the ionic compositions of the D region of the ionosphere on daily and seasonal scales. It is found that ion clusters dominate the total ion content up to altitudes of 95 km in winter and 80 km in summer.
Mesospheric Ozone Depletion Depending on Different Levels of Geomagnetic Disturbances and Seasons Irina Mironova, Dmitry Grankin, Eugene Rozanov Atmosphere, 2023 Energetic electron precipitation (EEP) into the atmosphere are considered to play an important role in the natural forcing of the ozone variability and dynamics of the middle atmosphere during magnetospheric and geomagnetic disturbances. Energetic electrons from the radiation belt spill out into the atmosphere during geomagnetic disturbances and cause additional ionization rates in the polar middle atmosphere. These rates of induced atmospheric ionization lead to the formation of radicals in ion-molecular reactions at the heights of the mesosphere with the formation of reactive compounds of odd nitrogen groups NOy and odd hydrogen groups HOx. These compounds are involved in catalytic reactions that destroy ozone. The percentage of ozone destruction can depend not only intensity of EEP but also on season where it happens. In this work, we study mesospheric ozone depletion depending on seasons and precipitating energetic electrons with energies from keV up to relativistic energies about 1 MeV, based on the NOAA POES satellites observations in 2003. For estimation ozone deplation we use a one-dimensional radiative-convective model with ion chemistry. As one of the main results, we show that, despite the intensity of EEP-induced ionization rates, polar mesospheric ozone cannot be destroyed by EEP in summer in the presence of UV radiation. In winter time, the maximum ozone depletion, at altitude of about 80 km, can reach up to 80% during strong geomagnetic disturbances. In fall and spring, the maximum ozone depletion is less intense and can reach 20% during strong geomagnetic disturbances. Linear relation of EEP induced maximum mesospheric ozone depletion depending on geomagnetic disturbances and seasons have been obtained.
Atmospheric Response to EEP during Geomagnetic Disturbances Dmitry Grankin, Irina Mironova, Galina Bazilevskaya, Eugene Rozanov, Tatiana Egorova Atmosphere, 2023 Energetic electron precipitation (EEP) is associated with solar activity and space weather and plays an important role in the Earth’s polar atmosphere. Energetic electrons from the radiation belt precipitate into the atmosphere during geomagnetic disturbances and cause additional ionization rates in the polar middle atmosphere. These induced atmospheric ionization rates lead to the formation of radicals in ion-molecular reactions at the heights of the mesosphere and upper stratosphere with the formation of reactive compounds of odd nitrogen NOy and odd hydrogen HOx groups. These compounds are involved in catalytic reactions that destroy the ozone. In this paper, we present the calculation of atmospheric ionization rates during geomagnetic disturbances using reconstructed spectra of electron precipitation from balloon observations; estimation of ozone destruction during precipitation events using one-dimensional photochemical radiation-convective models, taking into account both parameterization and ion chemistry; as well as provide an estimation of electron density during these periods.
Polar winter mesospheric ozone depletion during energetic electron precipitation Dmitriy Grankin, Irina Mironova, Eugene Rozanov Proceedings of SPIE the International Society for Optical Engineering, 2021 We present a study of the mesospheric ozone and chemical composition response to the highly energetic electron precipitations (EEP) recorded in winter during balloon flights over the polar latitudes. Ionization rates (IR) caused by the EEP were calculated considering the energy spectra and fluence retrieved from balloon observations. We analyze the response of the ozone-depleting components such as the odd nitrogen NOx and the hydrogen HOx groups and estimate the ozone (O3) depletion caused by the precipitating electrons with an energy of more than 30 keV. In the presented study, two 1D radiative-convective models with different methods of interpreting NOx and HOx , and processing the IR data are used. One of the model vesrions exploits parametrization of the of NOx and HOx production as a function of the ionization rate. The other one is 1-D radiative-convective model with interactive neutral and ion chemistry. The second model version is treated with the parametrization affecting ion chemistry has also been improved, so that we can now obtain the EEP effects on the atmospheric nitric acid (HNO3).
