Daria Kotova

1.    Kotova D.S., Klimenko M.V., Klimenko V.V., Zakharov V.E. Numerical Simulation of the Influence of the May 2–3, 2010 Geomagnetic Storm on HF Radio-Wave Propagation in the Ionosphere // Radiophysics and Quantum Electronics. 2014. V. 57. № 7. pp 467-477. doi: 10.1007/s11141-014-9529-2. 
2.    Klimenko M.V., Klimenko V.V., Bessarab F.S., Ratovsky K.G., Zakharenkova I.E., Nosikov I.A., Stepanov A.E., Kotova D.S., Vorobjev V.G., Yagodkina O.I. Influence of Geomagnetic Storms of September 26–30, 2011, on the Ionosphere and HF Radiowave Propagation. I. Ionospheric Effects // Geomagnetism and Aeronomy. 2015. V. 55. № 6. P. 744–762. doi:10.1134/S0016793215050072. 
3.    Kotova D.S., Klimenko M.V., Klimenko V.V., Zakharov V.E., Ratovsky K.G., Nosikov I.A., and Zhao B. Using IRI and GSM TIP model results as environment for HF radio wave propagation model during geomagnetic storms on September 26-29, 2011 // Advances in Space Research. 2015. V 56, P. 2012-2029. doi: 10.1016/j.asr.2015.05.009. 
4.    Kotova D.S., Zakharov V.E., Klimenko M.V., Klimenko V.V. Development of the Model of HF Radiowave Propagation in the Ionosphere // Russian Journal of Physical Chemistry B. 2015. Vol. 9. No. 6, pp. 983–991. doi: 10.1134/S1990793115050218. ISSN 1990-7931. 
5.    Klimenko M.V., Klimenko V.V., Bessarab F.S., Zakharenkova I.E., Vesnin A.M., Ratovsky K.G., Galkin I.A., Chernyak Iu.V., Yasyukevich Yu.V., Koren’kova N.A., Kotova D.S. Diurnal and longitudinal variations in the earth’s ionosphere in the period of solstice in conditions of a deep minimum of solar activity // Cosmic Research. 2016. V. 54, No. 1, P. 8-19. doi: 10.1134/S001095251601010X. 
6.    Kotova D.S., Klimenko M.V., Klimenko V.V., Zakharov V.E., Bessarab F.S., Korenkov Yu.N. Influence of January 2009 stratospheric warming on HF radio wave propagation in the low-latitude ionosphere // Journal Solar-Terrestrial Physics. 2016. V. 2, I. 4: p. 81-93. DOI: 10.12737/21880
7.    Kotova D.S., Klimenko M.V., Klimenko V.V., Zakharov V.E. Influence of Geomagnetic Storms of September 26–30, 2011, on the Ionosphere and HF Radiowave Propagation. II. Radiowave Propagation // Geomagnetism and Aeronomy. 2017. V. 57. № 3. P. 288-300. 

8.    Kotova D.S., Ovodenko V.B., Yasyukevichd Yu.V., Klimenko M.V., Mylnikova A.A., Kozlovsky A.E., Gusakov A.A. Correction of IRI-Plas and NeQuick Empirical Ionospheric Models at High Latitudes Using Data from the Remote Receivers of Global Navigation Satellite System Signals // Russian Journal of Physical Chemistry B. 2018. Vol. 12. No. 4, pp. 776–781. doi: 10.1134/S1990793118040127.

• Wood, Alan G.; Donegan-Lawley, Elizabeth E.; Clausen, Lasse; Spogli, Luca; Urbář, Jaroslav & Jin, Yaqi [Show all 20 contributors for this article] (2024). Statistical models of the variability of plasma in the topside ionosphere: 1. Development and optimisation. Journal of Space Weather and Space Climate. ISSN 2115-7251. 14. doi: 10.1051/swsc/2024002.
• Spogli, Luca; Jin, Yaqi; Urbář, Jaroslav; Wood, Alan G.; Donegan-Lawley, Elizabeth E. & Clausen, Lasse [Show all 20 contributors for this article] (2024). Statistical models of the variability of plasma in the topside ionosphere: 2. Performance assessment. Journal of Space Weather and Space Climate. ISSN 2115-7251. 14. doi: 10.1051/swsc/2024003.
• Enengl, Florine; Spogli, L.; Kotova, Daria; Jin, Yaqi; Oksavik, Kjellmar & Partamies, Noora [Show all 7 contributors for this article] (2024). Investigation of Ionospheric Small-Scale Plasma Structures Associated With Particle Precipitation. Space Weather. ISSN 1542-7390. 22(1). doi: 10.1029/2023SW003605.
• Ssessanga, Nicholas; Miloch, Wojciech Jacek; Clausen, Lasse & Kotova, Daria (2023). Performance Analysis of a Strong Constraint 4DVar and 4DEnVar on Regional Ionosphere Imaging. Space Weather. ISSN 1542-7390. 21(12). doi: 10.1029/2023SW003584. Full text in Research Archive
• Jin, Yaqi; Miloch, Wojciech Jacek; Kotova, Daria; Jacobsen, Knut Stanley; Stevanović, Đorđe & Clausen, Lasse [Show all 8 contributors for this article] (2023). Modeling TEC Irregularities in the Arctic Ionosphere Using Empirical Orthogonal Function Method. Space Weather. ISSN 1542-7390. 21(8). doi: 10.1029/2023SW003531. Full text in Research Archive
• Enengl, Florine; Kotova, Daria; Jin, Yaqi; Clausen, Lasse & Miloch, Wojciech Jacek (2023). Ionospheric plasma structuring in relation to auroral particle precipitation. Journal of Space Weather and Space Climate. ISSN 2115-7251. 13(4). doi: 10.1051/swsc/2022038.
• Kotova, Daria; Jin, Yaqi; Spogli, Luca; Wood, Alan G.; Urbar, Jaroslav & Rawling, James T. [Show all 11 contributors for this article] (2022). Electron density fluctuations from Swarm as a proxy for ground-based scintillation data: A statistical perspective. Advances in Space Research. ISSN 0273-1177. doi: 10.1016/j.asr.2022.11.042. Full text in Research Archive
• Jin, Yaqi; Kotova, Daria; Xiong, Chao; Brask, Steffen Mattias; Clausen, Lasse & Kervalishvili, Guram [Show all 8 contributors for this article] (2022). Ionospheric Plasma IRregularities - IPIR - data product based on data from the Swarm satellites. Journal of Geophysical Research (JGR): Space Physics. ISSN 2169-9380. 127(4). doi: 10.1029/2021JA030183.
• Wood, Alan G.; Alfonsi, Lucilla; Clausen, Lasse; Jin, Yaqi; Spogli, Luca & Urbář, Jaroslav [Show all 19 contributors for this article] (2022). Variability of Ionospheric Plasma: Results from the ESA Swarm Mission. Space Science Reviews. ISSN 0038-6308. 218(6). doi: 10.1007/s11214-022-00916-0. Full text in Research Archive
• Urbar, Jaroslav; Spogli, Luca; Cicone, Antonio; Clausen, Lasse; Jin, Yaqi & Wood, Alan G. [Show all 11 contributors for this article] (2022). Multi-scale response of the high-latitude topside ionosphere to geospace forcing. Advances in Space Research. ISSN 0273-1177. doi: 10.1016/j.asr.2022.06.045. Full text in Research Archive
• Kotova, Daria; Jin, Yaqi & Miloch, Wojciech Jacek (2022). Interhemispheric variability of the electron density and derived parameters by the Swarm satellites during different solar activity. Journal of Space Weather and Space Climate. ISSN 2115-7251. 12, p. 1–21. doi: 10.1051/swsc/2022007. Full text in Research Archive
• Skjæveland, Arnlaug; Kotova, Daria S. & Miloch, Wojciech J. (2021). Case Studies of Ionospheric Plasma Irregularities Over Queen Maud Land, Antarctica. Journal of Geophysical Research (JGR): Space Physics. ISSN 2169-9380. 126(10). doi: 10.1029/2021JA029963. Full text in Research Archive Show summary

  We use the first data set from the ground-based TEC and scintillation receiver located at the Norwegian Research Station Troll in Queen Maud Land, Antarctica to analyze in detail the ionospheric response during geomagnetic disturbances on February 26-27 and March 18-19, 2018. By combining the Troll data with complementary measurements (scintillation receivers, magnetometers, SuperDARN, DMSP satellites), we demonstrate that plasma irregularities above this part of Queen Maud Land can be associated with the expansion of the auroral oval, related structuring on its edges, as well as with strong flow shears in the evening and at nighttime, which are further modulated by the energetic particle precipitation. Phase scintillation indices correlate well with the magnetometer data.

• Kotova, Daria; Nosikov, I.A.; Klimenko, M.V. & Zakharov, V.E. (2021). Comparison оf Shooting Method and Variational Approach for Two-Point Ionospheric Ray Tracing. Bulletin of the Russian Academy of Sciences: Physics. ISSN 1062-8738. 85(3), p. 262–267. doi: 10.3103/S1062873821030114.
• Jin, Yaqi; Xiong, Chao; Clausen, Lasse Boy Novock; Spicher, Andres; Kotova, Daria & Brask, Steffen [Show all 9 contributors for this article] (2020). Ionospheric Plasma Irregularities Based on In Situ Measurements From the Swarm Satellites. Journal of Geophysical Research (JGR): Space Physics. ISSN 2169-9380. 125(7). doi: 10.1029/2020JA028103. Full text in Research Archive Show summary

  In this study, we present global climatological distributions of ionospheric plasma irregularities based on measurements by the Swarm satellites. These first global statistics obtained by direct, in situ measurements of plasma variations with Swarm confirm the presence of three main regions of strong ionospheric irregularities: the magnetic equator extending from postsunset to early morning, in the auroral ovals (from dayside cusp to nightside), and inside the polar caps. At equatorial latitudes, ionospheric irregularities form two bands of enhanced plasma fluctuations centered around ±10° magnetic latitude. Due to different plasma processes, ionospheric irregularities at high and low latitudes show different distributions. Though the averaged intensity of plasma irregularities is weaker at equatorial latitudes than at high latitudes, the occurrence rate of significant plasma fluctuations (corresponding to extreme events) is much higher at the equator than that at high latitudes. Equatorial irregularities display clear seasonal and longitudinal variations; that is, they are most prominent over South America during the December solstice and are located over Africa during the June solstice. The magnitude of ionospheric irregularities at all latitudes is strongly controlled by the solar activity. Ionospheric irregularities become significantly weaker after 2016 during the current declining phase of solar activity. The interplanetary magnetic field Bz modulates the occurrence of ionospheric irregularities at both high and low latitudes.

• Ovodenko, Vladimir; Klimenko, Maxim; Zakharenkova, Irina; Oinats, Alexey; Kotova, Daria & Nikolaev, Alexander V. [Show all 14 contributors for this article] (2020). Spatial and Temporal Evolution of Different‐Scale Ionospheric Irregularities in Central and East Siberia During the 27–28 May 2017 Geomagnetic Storm. Space Weather. ISSN 1542-7390. 18(6). doi: 10.1029/2019SW002378. Full text in Research Archive Show summary

  We present a multi‐instrumental study of ionospheric irregularities of different scales (from tens of centimeters to few kilometers) observed over the Central and East Siberia, Russia, during a moderate‐to‐strong geomagnetic storm on 27–28 May 2017. From high‐frequency (HF) and ultrahigh‐frequency (UHF) radar data, we observed an intense auroral backscatter developed right after the initial phase of the geomagnetic storm. Additionally, we examined variations of Global Positioning System (GPS)‐based ROT (rate of TEC changes, where TEC is total electron content) for available GPS receivers in the region. Ionosondes, HF, and UHF radar data exhibited a presence of intense multi‐scale ionospheric irregularities. We revealed a correlation between different‐scale Auroral/Farley‐Buneman ionospheric irregularities of the E layer during the geomagnetic storm. The combined analysis showed that an area of intense irregularities is well connected and located slightly equatorward to field‐aligned currents (FACs) and auroral oval at different stages of the geomagnetic storm. An increase and equatorward displacement of Region 1 (R1)/Region 2 (R2) FACs leads to appearance and equatorward expansion of ionospheric irregularities. During downward (upward) R1 FAC and upward (downward) R2 FAC, the eastward and upward (westward and downward) E × B drift of ionospheric irregularities occurred. Simultaneous disappearance of UHF/HF auroral backscatter and GPS ROT decrease occurred during a prolonged near noon reversal of R1 and R2 FAC directions that accompanied by R1/R2 FAC degradation and disappearance of high‐energy auroral precipitation.

• Kotova, Daria; Zakharenkova, Irina; Klimenko, Maxim; Ovodenko, Vladimir; Tyutin, Ilya & Chugunin, Dmitry V. [Show all 15 contributors for this article] (2020). Formation of Ionospheric Irregularities in the East Siberian Region during the Geomagnetic Storm of May 27─28, 2017. Russian Journal of Physical Chemistry B. ISSN 1990-7923. 14(2), p. 377–389. doi: 10.1134/S1990793120020232. Show summary

  Results of studying different-scale ionospheric irregularities on the basis of multi-instrumental data, obtained in the East Siberian region of Russia during the geomagnetic storm of May 27–28, 2017, are presented. Spatial inhomogeneities of electron density in the ionosphere were observed through data from ground-based receivers of signals of global navigational satellite systems and on the basis of direct measurements of electron density in low-orbit satellites. An intense radio aurora was seen in UHF radar data just after the initial phase of geomagnetic storm. At the same time, we recorded fluctuations of the total electron content from data of GPS receivers and the presence of E-layer irregularities by data of the ionosonde in Norilsk. The time of irregularity recording by different instruments is consistent with the spatiotemporal changes in field-aligned currents of the second zone, obtained from data of AMPERE low-orbit satellite system.

• Kotova, Daria; Ovodenko, Vladimir; Yasyukevich, Yury; Klimenko, Maxim; Ratovsky, Konstantin & Mylnikova, Anna [Show all 11 contributors for this article] (2019). Efficiency of updating the ionospheric models using total electron content at mid- and sub-auroral latitudes. GPS Solutions. ISSN 1080-5370. 24. doi: 10.1007/s10291-019-0936-x. Show summary

  Describing the current ionospheric conditions is crucial to solving problems of radio communication, radar, and navigation. Techniques to update ionospheric models using current measurements found a wide application to improve the ionosphere description. We present the results of updating the NeQuick and IRI-Plas empirical ionosphere models using the slant total electron content observed by ground-based GPS/GLONASS receivers. The updating method is based on calculating the effective value of the solar activity index, which allows minimizing the discrepancy between the measured and the modelcalculated slant TEC. We estimated the updating efficiency based on the foF2 observational data obtained by ionosonde measurements. We calculated the data for 4 stations: Irkutsk, Norilsk, Kaliningrad, and Sodankylä. We analyzed 4 days in 2014: March 22, June 22, September 22, and December 18. We found that, in some cases, upon updating, the IRI-Plas underestimates the foF2, whereas NeQuick, on the contrary, overestimates it. We found a seasonal dependence of the updating efficiency of the ionosphere model using slant TEC. Possible causes of this dependence might be associated with the seasonal dependence of the correctness of model’s reproduction of the latitude–longitude TEC distribution. In general, we found the low level of the updating efficiency of the foF2 using slant TEC. This can be mainly explained by the fact that the models describe the electron density vertical profile and ionospheric slab thickness incorrectly

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• Chugunin, Dmitry V.; Kotova, Daria; Sinevich, A. A.; Chernyshov, Alexander A. & Miloch, Wojciech Jacek (2023). Scintillations of GNSS receivers in the subauroral region in the southern hemisphere. Show summary

  The work studies the possible influence of a polarization jet/SAID (SubAuroral ion Drift) on the phase scintillations of GNSS receivers. We consider the geomagnetic case of March 18, 2018, when, according to the DMSP satellite data, a polarization jet/SAID was observed over the area of Antarctica, where two GNSS receivers were located. For a more complete analysis, this study also uses Super Dual Auroral Radar Network (SuperDARN) observations as well as Swarm and Norsat-1 satellite data for this geomagnetic substorm. From the analysis of the data, it is concluded that at the moment of auroral activity intensification, an increased intensity of phase scintillations was observed in the region of the polarization jet/SAID in the subauroral ionosphere.

• Kotova, Daria; Sinevich, A. A.; Chernyshov, Alexander A.; Chugunin, Dmitry V. & Miloch, Wojciech Jacek (2023). Effect of SAID on the Development of Ionospheric Scintillations and Irregularities in the Subauroral Region. Show summary

  The polarization jet, which is also known as the subauroral ion drift (SAID), is related to fast westward ion drifts. SAID is one of the main signatures of a geomagnetic disturbance in the subauroral ionosphere at the altitudes of the F-layer. SAID is a projection of the plasmapause onto the altitudes of the ionosphere, mainly during substorm periods when the AE index reaches more than 500 nT. SAID is characterized by a narrow jet (about 2º) and can have a duration of about several hours (in longitude). Plasma speed in SAID can reach several kilometers per second. Such high plasma velocities can lead to ionospheric scintillations affecting trans-ionospheric radio signals. For example, when radio signals of the Global Navigation Satellite System (GNSS) pass through ionospheric irregularities, receivers on the ground can observe rapid fluctuations in amplitude and/or phase of the incoming wave. These fluctuations can lead to serious deterioration of radio communication or navigational services. In this work, we analyze the possible influence of a polarization jet/SAID on the development of ionospheric scintillations and irregularities in the subauroral region. We consider the geomagnetic event on March 18, 2018 (with Kp = 6 and SYM-H = −53 nT), when according to the DMSP satellite data, a polarization jet/SAID was observed close to two GNSS Ionospheric Scintillation and TEC Monitor (GISTM) receivers in Antarctica (SANAE IV and Troll stations). For a more complete analysis, we also use data from nearby magnetometers at the Neumayer and SANAE IV stations, Super Dual Auroral Radar Network (SuperDARN) at SANAE IV, as well as from the Swarm and Norsat-1 satellites during considered substorm activity. We conclude that at the moment of auroral activity intensification, an increase in the magnitude of phase scintillation index (σφ) was observed in the region of the polarization jet/SAID in the subauroral ionosphere indicating high structuring of the ionospheric plasma. DK, WM acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (ERC Consolidator Grant agreement No. 866357, POLAR-4DSpace). The work of ААS and AAC was supported by the Theoretical Physics and Mathematics Advancement Foundation "BASIS".

• Enengl, Florine; Spogli, Luca; Kotova, Daria; Jin, Yaqi; Oksavik, Kjellmar & Partamies, Noora [Show all 7 contributors for this article] (2023). On the formation of small-scale irregularities driven by auroral particle precipitation.
• Kotova, Daria; Jin, Yaqi & Miloch, Wojciech Jacek (2022). Interhemispheric investigation of variability of ionospheric parameters measured by the Swarm satellites for quiet geomagnetic conditions. Show summary

  The use of satellite data allows us to study the variability of ionospheric plasma parameters globally without references to ground stations or receivers in different regions of the Earth. The Swarm mission, which was launched in November 2013 and is still operational, allows us to investigate the effects of decreasing solar activity on ionospheric variability. We use the Swarm in-situ measurements of the electron density and derived parameters that have been combined into a unique dataset called the Ionospheric Plasma IRregularities product (IPIR) [1]. IPIR provides characteristics of the plasma variability along the orbit and gives information on plasma density structures in the ionosphere in terms of their amplitudes, gradients and spatial scales. In this study, we focused on distributions and statistics of these parameters in the Northern and Southern hemispheres for quiet geomagnetic conditions. Our results provide information on the shape of the distribution and probability density functions of electron density and derived ionospheric parameters that can be used as a baseline important for other modeling studies. Understanding the distribution of such parameters in the context of the geomagnetic activity and selected ionospheric regions can have implications for the development of new satellite instruments and for the accuracy of GNSS precise positioning. This work was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Consolidator Grant agreement No. 866357, POLAR-4DSpace).

• Kotova, Daria; Jin, Yaqi; Spogli, Luca; Wood, Alan G.; Alfonsi, Lucilla & Urbar, Jaroslav [Show all 9 contributors for this article] (2022). Comparison Of Electron Density Fluctuations From Swarm Satellites With The Ground-based Scintillation Data: A Statistical Perspective. Show summary

  The Swarm satellite mission is actively used to conduct various studies of the ionosphere, focusing on such aspects as the electric and magnetic fields or plasma temperature, structuring and irregularities. The mission is a constellation of three satellites that were launched in November 2013 and have been collecting data continuously since then. We use a global product based on the Swarm satellite measurements that characterizes ionospheric irregularities and fluctuations. The IPIR (Ionospheric Plasma IRregularities product) provides in-situ characteristics of plasma density structures in the ionosphere, of plasma irregularities in terms of their amplitudes, gradients and spatial scales and assigns them to geomagnetic regions. Ionospheric irregularities and fluctuations are often the cause increases the error in position, velocity, time determination based on Global Navigation Satellite Systems (GNSS), which signals pass through the ionosphere. The IPIR provides an indication, in the form of a numerical value index, on severity of irregularities for the integrity of trans-ionospheric radio signals and hence the accuracy of GNSS precise positioning. This work demonstrates that data from the Swarm satellite's flyby height can be used as a proxy for ground-based scintillation data. We compare two datasets from Swarm satellites (with 1-second resolution) and from groundbased scintillation receivers (with 1-minute resolution). To consider the measured parameters for the same area, we find time intervals when the Swarm satellites pass over the field of view of the ground-based Global Positioning System (GPS) receiver. A geometry with an elevation angle of 30° above the receiver was used to calculate these passes. We also performed an azimuthal selection of the GNSS data according to Swarm satellite fly. We used only those GPS satellites that flew near the position of the Swarm satellite in azimuth sector ±10°. We provide validations of the IPIR product against the ground-based measurements, focusing on GPS TEC and scintillation data in low and high-latitudes regions in different longitudinal sectors. We calculate median, mean, maximum and standard deviation values for parameters for both dataset for each conjunction point (for each GPS satellite and Swarm). We observe a weak trend of stronger scintillations with an increasing IPIR index, where the IPIR index presents a product of amplitudes and temporal variations in plasma densities.

• Kotova, Daria (2022). Modelling of HF radio waves propagation in the ionosphere. Show summary

  Although high frequency (HF) radio waves are losing their importance these days, we cannot underestimate their vital applications such as communication of transpolar flights, backup emergency messaging, and global ionospheric sensing. The dynamic of various ionospheric parameters, in particular electron density, significantly affects radio communication. This fact is extremely important for the operation of air traffic and navy, over-the-horizon radars and Global Navigation Satellite Systems (including GPS and GLONASS). The ionospheric disturbances of a different nature lead to positioning problems, as well as radio communication problems, up to its complete disappearance (especially in high latitudes). One of the main approaches to solving the problem of modelling the HF radio waves propagation is the geometrical optics approximation. To calculate the HF ray paths in both radiophysics and seismology the method of characteristics is widely used. The fundamental problem of calculating and predicting ray paths in inhomogeneous media is often formulated as a boundary problem, where the positions of transmission and receiver are known in advance. Due to its complexity, this kind of problem is traditionally reduced to the Cauchy problem, where the solution of the eikonal equation by the method of characteristics is repeatedly used for the selected initial conditions as azimuth and elevation angles. This procedure is the most time-consuming part of the solution. Recently, there has been an active development of approaches to solving the boundary value problem based on variational method. This method allows to solve the boundary problem directly, without resorting to the "shooting methods". However, all HF radio waves propagation models depend on the environmental model used to describe the actual ionospheric conditions. Therefore, accurate 3D ionospheric specification is required in order to solve the applied problems of radio wave propagation (RWP). In this talk, we will consider the main approaches to the modelling of HF RWP, possible ways of applying, the strengths and weaknesses of each approach, as well as how to obtain modelling results close to real conditions. This work was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Consolidator Grant agreement No. 866357, POLAR-4DSpace). https://uit.no/tavla/artikkel/762779/space-_plasma-_and_climate_physics_meeting_of_no

• Kotova, Daria; Jin, Yaqi; Spogli, Luca; Wood, Alan G.; Urbar, Jaroslav & Rawlings, James T. [Show all 11 contributors for this article] (2022). Electron density fluctuations from Swarm as a proxy for ground-based scintillation data: A statistical perspective.
• Miloch, Wojciech Jacek; Kotova, Daria & Jin, Yaqi (2022). Ionospheric plasma structuring over Antarctica based on satellite and ground observations .
• Miloch, Wojciech Jacek; Kotova, Daria; Lybekk, Bjørn & Trondsen, Espen (2022). Space weather studies at the Troll Ionospheric Observatory in Dronning Maud Land, Antarctica .
• Enengl, Florine; Kotova, Daria; Jin, Yaqi; Clausen, Lasse & Miloch, Wojciech Jacek (2022). Ionospheric plasma irregularities in relation to dynamic auroral forms.
• Kotova, Daria; Jin, Yaqi; Brask, Steffen Mattias; Spogli, Luca; Wood, Alan G. & Miloch, Wojciech Jacek (2022). Comparison of electron density fluctuations measured by Swarm satellites with the ground-based scintillation data.
• Kotova, Daria; Jin, Yaqi & Miloch, Wojciech Jacek (2022). Erratum: Interhemispheric variability of the electron density and derived parameters by the Swarm satellites during different solar activity (J. Space Weather Space Clim. (2022) 12 (12) DOI: 10.1051/swsc/2022007). Journal of Space Weather and Space Climate. ISSN 2115-7251. 12. doi: 10.1051/swsc/2022013.
• Enengl, Florine; Kotova, Daria & Miloch, Wojciech Jacek (2021). On the Contribution of Particle Precipitation to Ionospheric Plasma Structuring. Show summary

  Auroral particle precipitation potentially plays a main role in ionospheric plasma structuring. The impact of particle precipitation on plasma structuring are investigated using multi point measurements from scintillation receivers and all sky cameras from Longyearbyen, Ny Ålesund and for the first time from Hornsund on Svalbard. This provides us with the unique possibility of studying the auroral dynamics in a spatial and temporal evolution. Here we consider several case studies to investigate which auroral forms have strongest impact on transionospheric radio waves. We demonstrate that plasma structuring impacting the GNSS signals are largest at the edges of auroral arcs in the direction of their propagation. High energetic particle precipitation, reaching altitudes down to 150 km may be a driver for phase scintillations through structuring. High values of phase scintillation indices can be observed even shortly after strong visible aurora and can then remain significant at low intensities of the aurora.

• Kotova, Daria & Miloch, Wojciech Jacek (2021). Study of the GNSS phase scintillation associated with auroral activity over Queen Maud Land, Antarctica. Show summary

  This study uses the dataset from the all-sky camera and the ground-based TEC and scintillation receiver installed in Antarctica at the Norwegian Research Station Troll. The station is located just on the equatorward edge of the quiet auroral oval. Thus, the observatory is in an optimal location to study the ionospheric response to geomagnetic disturbances. The all-sky camera was calibrated. In addition, we use geomagnetic indices and information about the solar wind from NASA's OMNIWeb Service, in-situ data onboard low Earth orbiting satellites (Defense Meteorological Satellite Program (DMSP), Swarm mission), and the Super Dual Auroral Radar Network (SuperDARN). Together with the ground-based GNSS scintillation receiver, a comprehensive analysis of the reasons for observing scintillations over the Troll station during the period of geomagnetic disturbances was carried out. The relationship between the activation of aurora and severe phase scintillations is shown.

• Kotova, Daria (2021). Comprehensive analysis of scintillations over the Troll station using the all-sky camera and GNSS receiver. Show summary

  In this study, we use the first data from the all-sky camera installed in Antarctica at the Norwegian Research Station Troll. The auroral all-sky camera calibration was calibrated. Together with the ground-based TEC and scintillation receiver located there, a comprehensive analysis of the reasons for observing scintillations over the Troll station during the period of geomagnetic disturbances was carried out.

• Kotova, Daria; Jin, Yaqi & Miloch, Wojciech Jacek (2021). Investigation of interhemispheric variability of ionospheric parameters by the Swarm satellites for different solar activity. Show summary

  The use of satellite data allows us to study the variability of ionospheric plasma parameters globally without references to ground stations or receivers in different regions of the Earth. The Swarm mission, which was launched in 2014 and is still operational, allows us to investigate the effects of decreasing solar activity on the ionospheric variability. In our study, we use the Swarm in-situ measurements of the electron density and derived parameters. This dataset provides characteristics of the plasma variability along the orbit and gives information on plasma density structures in the ionosphere in terms of their amplitudes, gradients and spatial scales. In this study, we focused on the investigation of variability of these parameters in northern and southern hemispheres. Understanding of the distribution of such parameters in the context of the solar activity level and selected ionospheric regions can have implications for the development of new satellite instruments and for the accuracy of GNSS precise positioning.

• Miloch, Wojciech Jacek; Jin, Yaqi; Xiong, Chao; Brask, Steffen Mattias; Kotova, Daria & Kervalishvili, Guram [Show all 9 contributors for this article] (2020). Ionospheric Plasma IRregularities (IPIR data products).
• Kotova, Daria; Klimenko, Maxim; Vesnin, Artem; Klimenko, Vladimir V.; Zakharov, Veniamin & Rogov, Denis D. [Show all 7 contributors for this article] (2020). SIMULATION OF OBLIQUE SOUNDING IONOGRAMS DURING ST. PATRICK'S DAY 2015 GEOMAGNETIC STORM: VALIDATION AND INVESTIGATION OF THE INFLUENCE OF THE EARTH'S MAGNETIC FIELD. Proceedings of International Conference "Atmosphere, ionosphere, safety" (AIS-2020). p. 132–135.
• Kotova, Daria; Jin, Yaqi; Brask, Steffen; Cilliers, Pierre & Miloch, Wojciech Jacek (2020). Comparison of characteristics of electron density fluctuations from Swarm satellites with the ground-based scintillation data.
• Kotova, Daria; Jin, Yaqi & Miloch, Wojciech Jacek (2020). Variability of ionospheric parameters by the Swarm satellites for different solar activity.
• Kotova, Daria; Nosikov, Igor; Klimenko, Maxim & Bessarab, Pavel (2020). Comparison of two approaches for a point-to-point radio wave ray tracing in anisotropic medium.
• Miloch, Wojciech Jacek; Kotova, Daria; Jin, Yaqi; Xiong, Chao; Brask, Steffen & Kervalishvili, Guram [Show all 9 contributors for this article] (2019). Ionospheric plasma irregularities studied globally with the Swarm satellites .
• Kotova, Daria; Jin, Yaqi & Miloch, Wojciech Jacek (2019). Comparison of ionospheric plasma irregularities measured by Swarm with the ground-based GPS scintillation data. Show summary

  Ionospheric irregularities are often the cause of GNSS precise positioning errors, as well as disruption of radio communications in the HF range. The reason for the occurrence of these irregularities can be various non-stationary processes in the near-Earth space plasma that depend on the response of the ionosphere to the variations in the near Earth space. Therefore, the study of ionospheric irregularities is an urgent scientific and applied problem. In this study we use a global product based on the Swarm satellite measurements that characterizes ionospheric irregularities and fluctuations. The IPIR (Ionospheric Plasma IRregularities product) provides characteristics of plasma density structures in the ionosphere, of plasma irregularities in terms of their amplitudes, gradients and spatial scales and assigns them to geomagnetic regions and consequently to predominant plasma processes. It also provides indication, in the form of a numerical value index, on their severity for the integrity of trans-ionospheric radio signals and hence the accuracy of GNSS precise positioning. In this work we made validations of the IPIR product against the ground-based measurements, focusing on GPS TEC and scintillation data in low latitudes regions.

• Skjæveland, Arnlaug Høgås; Kotova, Daria & Miloch, Wojciech Jacek (2019). Investigation of GPS phase scintillations at Troll station during geomagnetic disturbances in 2018. Show summary

  Ionospheric phenomena as a response to geomagnetic activity can be different at both hemispheres, in particular at high latitudes, due to the structure of the ionosphere, orientation of the interplanetary magnetic field and structure of the Earth magnetic field. This may have implications on large scale modeling and space weather forecasting. To understand these aspects, a significant number of studies which include both hemispheres are required. In order to study the asymmetry between the northern and southern hemispheres at high latitudes, we employ the GNSS TEC and scintillation monitors. We use data from a GNSS receiver at Troll station in Antarctica together with corresponding datasets from the northern hemisphere. We carry out detailed study of several representative events for different geomagnetic conditions. We characterize the GPS phase scintillations in the context of interhemispheric asymmetries, and also using other supportive ground based and satellite observations. This is the first study with data from the recently established ionospheric observatory at Troll station in Antarctica. It also forms a ground for more statistical study of interhemispheric asymmetries, where the first results are also shown.

• Kotova, Daria; Nosikov, Igor & Klimenko, Maxim (2019). Comparison of two approaches for point-to-point ray tracing of HF waves in the ionosphere.
• Kotova, Daria; Ovodenko, Vladimir; Klimenko, Maxim; Karpov, Mikhail; Ratovsky, Konstantin & Korenkova, Nina [Show all 8 contributors for this article] (2019). Statistical analysis of results of updating the ionospheric model IRI-Plas from slant total electron content.

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