Morphology of Traveling Wave Disturbances Recorded in Eastern Siberia in 630 nm Atomic Oxygen Emission

Our paper presents the results of investigating wave structures detected in 630 nm atomic oxygen emission intensity (airglow height is ~180–300 km). The study employs data from a wide-angle optical system installed at the Geophysical Observatory of the ISTP SB RAS (51°48′ N, 103°04′ E). It describes the algorithm to identify wave disturbances and determine their main parameters in the optical system images. The results obtained due to automatic processing of 2014–2021 data archives are presented. The most probable values of the wave disturbances propagation velocity are about 80 m/s. The horizontal wavelengths and periods are in the range of ~30–400 km and 60–120 min, respectively. The predominant direction of disturbances propagation is to the southwest. The received data of optical and radio observations are compared. We found both similarities and differences in the wavelike structures direction, which are to be investigated in the future

Statistical Analysis and Interpretation of High-, Mid- and Low-Latitude Responses in Regional Electron Content to Geomagnetic Storms

Geomagnetic storm is one of the most powerful factors affecting the state of the Earth’s ionosphere. Revealing the significance of formation mechanisms for ionospheric storms is still an unresolved problem. The purpose of the study is to obtain a statistical pattern of the response in regional electron content to geomagnetic storms on a global scale to interpret the results using the upper atmosphere model (the Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere), to make the detailed comparison with the thermospheric storm concept, and to compare the obtained pattern with results from previous statistical studies. The regional electron content is calculated based on the global ionospheric maps data, which allows us to cover the midlatitude and high-latitude zones of both hemispheres, as well as the equatorial zone. Most of the obtained statistical pattern agrees with the thermospheric storm concept and with the previous statistical studies: ionospheric responses at ionospheric storm main phases including their seasonal dependences for the high- and midlatitudes and some features of ionospheric responses at recovery phases. However, some of the statistical patterns are inconsistent with the thermospheric storm concept or contradicts the previous statistical studies: negative midlatitude ionospheric responses at recovery phases in the local winter, the domination of the spring response in the equatorial zone, seasonal features of the positive after-effects, the interhemispheric asymmetry of ionospheric responses, and the prestorm enhancement. We obtained that the contribution of electric field to the interpretation of the zonal and diurnal averaged storm-time regional electron content (REC) disturbances is insignificant. The positive after-storm effects at different latitudes are caused by n(O) disturbances

Morphology of Traveling Wave Disturbances Recorded in Eastern Siberia in 630 nm Atomic Oxygen Emission

Our paper presents the results of investigating wave structures detected in 630 nm atomic oxygen emission intensity (airglow height is ~180–300 km). The study employs data from a wide-angle optical system installed at the Geophysical Observatory of the ISTP SB RAS (51°48′ N, 103°04′ E). It describes the algorithm to identify wave disturbances and determine their main parameters in the optical system images. The results obtained due to automatic processing of 2014–2021 data archives are presented. The most probable values of the wave disturbances propagation velocity are about 80 m/s. The horizontal wavelengths and periods are in the range of ~30–400 km and 60–120 min, respectively. The predominant direction of disturbances propagation is to the southwest. The received data of optical and radio observations are compared. We found both similarities and differences in the wavelike structures direction, which are to be investigated in the future

Winter anomaly in NmF2 and TEC: when and where it can occur

For the first time, by using a regression procedure, we analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (Nm F2) and in the Total Electron Content (TEC) on a global scale. We used the data from global ionospheric maps for 1998–2015, from GPS radio occultation observations with COSMIC, CHAMP, and GRACE satellites for 2001–2015, and ground-based ionosonde data. The fundamental features of the winter anomaly in Nm F2 and in TEC (spatial distribution and solar activity dependence) are similar for these parameters. We determined the regions, where the winter anomaly may be observed in principle, and the solar activity level, at which the winter anomaly may be recorded in different sectors. A growth in geomagnetic disturbance or in the solar activity level is shown to facilitate the winter anomaly intensity increase. Longitudinal variations in the winter anomaly intensity do not conform partly to the generally accepted Rishbeth theory. We consider the obtained results in the context of spatial and solar cycle variations in O/N2 ratio and thermospheric meridional wind. Additionally, we briefly discuss different definitions of the winter anomaly

Winter anomaly in

For the first time, by using a regression procedure, we analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (Nm F2) and in the Total Electron Content (TEC) on a global scale. We used the data from global ionospheric maps for 1998–2015, from GPS radio occultation observations with COSMIC, CHAMP, and GRACE satellites for 2001–2015, and ground-based ionosonde data. The fundamental features of the winter anomaly in Nm F2 and in TEC (spatial distribution and solar activity dependence) are similar for these parameters. We determined the regions, where the winter anomaly may be observed in principle, and the solar activity level, at which the winter anomaly may be recorded in different sectors. A growth in geomagnetic disturbance or in the solar activity level is shown to facilitate the winter anomaly intensity increase. Longitudinal variations in the winter anomaly intensity do not conform partly to the generally accepted Rishbeth theory. We consider the obtained results in the context of spatial and solar cycle variations in O/N2 ratio and thermospheric meridional wind. Additionally, we briefly discuss different definitions of the winter anomaly