Session ST3.1

[Programme]

ST3.1 | Open Session on Ionosphere and Thermosphere

Open Session on Ionosphere and Thermosphere

Convener: Dalia Buresova | Co-conveners: Tobias Verhulst, Jaroslav Urbar

Orals

| Tue, 25 Apr, 08:30–10:15 (CEST)

Room 1.14

Posters on site

| Attendance Tue, 25 Apr, 14:00–15:45 (CEST)

Hall X4

Posters virtual

| Attendance Tue, 25 Apr, 14:00–15:45 (CEST)

vHall ST/PS

The Earth's ionosphere embedded in the thermosphere is a coupled system influenced by Solar activity and magnetospheric processes from above, as well as by upward propagating disturbances from lower atmospheric layers. This open session is suitable for contributions on all aspects of ionospheric and thermospheric physics, in particular concerning ionospheric disturbances of different origin and their effects on modern human technologies. The session invites theoretical studies, (multi)instrumental ground-based and space-based observations, simulations and modelling studies that address the dynamics of the ionosphere, concerning transient events, plasma waves and irregularities, as well as large-scale dynamics and ionospheric and thermospheric climate. Contributions dealing with magnetospheric forcing are sought in the areas of ionospheric disturbances caused by CME- and CIR/CH HSS-related storms and substorms. New results that focus on investigation of latitudinal, seasonal and hemispheric differences in ionospheric response to storm induced disturbances are especially appreciated. Also ionospheric effects from other sources, such as the solar terminator, solar eclipses, seismic activity or antropogetic explosions, are welcome. As for forcing by the lower atmosphere, contributions are sought that focus on atmospheric waves, wave-wave and wave-mean flow interactions, atmospheric electricity and electrodynamic coupling processes.

Orals: Tue, 25 Apr | Room 1.14

Chairpersons: Tobias Verhulst, Dalia Buresova, Jaroslav Urbar

Open Session on Ionosphere and Thermosphere

08:30–08:35

5-minute convener introduction

08:35–08:55

EGU23-9536

solicited

Highlight

Virtual presentation

Magnetic storms during the space age: Occurrence and relation to varying solar activity

Kalevi Mursula, Timo Qvick, Lauri Holappa, and Timo Asikainen

We review here the occurrence of magnetic storms during the space age (1957 - 2021), as observed by two storm indices, the Dst index and the Dxt index. We study the solar sources of storms, describe the dramatic changes in the different types of storms during the space age, and explain these changes in terms of the long-term change of solar activity and solar magnetic fields during the decline of the Modern Grand Maximum.

We find 2526/2743 magnetic storms in the Dxt/Dst index, out of which 45% are weak (-50 nT < Dxt/Dst ≤ -30 nT), 40% moderate (-100 nT < Dxt/Dst ≤ -50 nT), 12% intense (200 nT < Dxt/Dst ≤ -100 nT) and 3% major (Dxt/Dst ≤ -200 nT) storms. Occurrence of storms in space age follows the slow decrease of sunspot activity and the related change in solar magnetic structure. We quantify the sunspot - CME storm relation in the five cycles of space age. We explain how the varying solar activity changes the structure of the heliospheric current sheet (HCS) and how this affects the HSS/CIR storms.

Space age started with a record number of storms in 1957 - 1960, with roughly one storm per week. Solar polar fields attained their maximum in cycle 22, which led to an exceptionally thin HCS, and a space age record of large HSS/CIR storms in 1990s. In the minimum of cycle 23, for the only time in space age, CME storm occurrence reduced below that predicted by sunspots. Weak sunspot activity since cycle 23 has weakened solar polar fields and widened the HCS, which has decreased the occurrence of large and moderate HSS/CIR storms. Moreover, because of the wide HCS, the Earth has spent 50% of its time in slow solar wind since cycle 23. The wide HCS has also made large and moderate HSS/CIR storms to occur in the early declining phase in recent cycles, while in the more active cycles 20-22 they occurred in the late declining phase.

How to cite: Mursula, K., Qvick, T., Holappa, L., and Asikainen, T.: Magnetic storms during the space age: Occurrence and relation to varying solar activity, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9536, https://doi.org/10.5194/egusphere-egu23-9536, 2023.

08:55–09:05

EGU23-2325

On-site presentation

Dual boundary coordinates in polar magnetosphere-ionosphere studies

Angeline Burrell, Gareth Chisham, and Kate Zawdie

The high latitude ionosphere, which coincides with the Arctic and Antarctic regions, is a complex region that is strongly coupled with the magnetosphere, neutral atmosphere, and the solar wind. The high latitude ionosphere may be divided into two regions based on the portion of the magnetosphere to which the ionosphere is connected. The most poleward region, the polar cap, is the area characterized by open magnetic field lines that connect directly to the interplanetary magnetic field (IMF) instead of closing in the opposite hemisphere. Within the polar cap, ionospheric plasma moves anti-sunward and HF propagation paths between a transmitter and receiver may occur through reflection in either the E region or F region of the ionosphere. Just equatorward of the polar cap is the auroral oval, a region that experiences high amounts of particle precipitation and energy transfer between the magnetosphere and ionosphere along closed magnetic field lines. The equatorward edge of the auroral oval marks the beginning of the mid-latitudes. Defining high latitude coordinates relative to these physically significant boundaries has implications for statistical studies, modeling applications, and research combining magnetospheric and ionospheric data. This study explores the impact of using single or multiple boundaries on such high latitude research efforts, and presents a tool to aid this research.

How to cite: Burrell, A., Chisham, G., and Zawdie, K.: Dual boundary coordinates in polar magnetosphere-ionosphere studies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2325, https://doi.org/10.5194/egusphere-egu23-2325, 2023.

09:05–09:15

EGU23-17588

On-site presentation

NASA’s Geospace Dynamics Constellation (GDC) mission: a multi-spacecraft mission to explore the ionosphere-thermosphere

Douglas Rowland, Katherine Garcia-Sage, Larry Kepko, Jared Bell, Laila Andersson, Phillip Andersson, Mark Moldwin, Daniel Gershman, and Mehdi Benna

The Geospace Dynamics Constellation (GDC) is NASA's next strategic Living With a Star mission. GDC's goals are: 1) Understand how the high-latitude ionosphere-thermosphere system responds to variable solar wind/magnetosphere forcing; and 2) Understand how internal processes in the global ionosphere-thermosphere system redistribute mass, momentum, and energy.

Planned for launch by the end of the decade, GDC will use six identical observatories, each identically instrumented to fully characterize the magnetospheric drivers of the I-T system as well as the global response of the ionized and neutral gases. GDC will do this with a series of orbital conegurations that will enable it to study the widest range of spatial and temporal scales to date, ranging from hundreds of kilometers and several seconds to tens of minutes, and extending through the regional to the global scale.

This poster presents GDC's current status, measurement capabilities, sampling scheme, and model development efforts and show how GDC will et into the larger Heliophysics ecosystem, by 1) obtaining critically needed scientiec observations; 2) providing a source for real-time space weather and situational awareness, as well as retrospective studies to further the science of space weather; 3) serving as a "strategic hub" for other space-based and ground- based efforts that want to leverage GDC to perform complementary science.

How to cite: Rowland, D., Garcia-Sage, K., Kepko, L., Bell, J., Andersson, L., Andersson, P., Moldwin, M., Gershman, D., and Benna, M.: NASA’s Geospace Dynamics Constellation (GDC) mission: a multi-spacecraft mission to explore the ionosphere-thermosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17588, https://doi.org/10.5194/egusphere-egu23-17588, 2023.

09:15–09:25

EGU23-2700

On-site presentation

Rapidly changing ionospheric structures inferred the by International LOFAR Telescope

Alan Wood, Gareth Dorrian, Ben Boyde, Richard Fallows, and Maaijke Mevius

The Low Frequency Array (LOFAR) is designed to observe the early universe at radio wavelengths. When radio waves from a distant astronomical source traverse the ionosphere, structures in the plasma affect the signal. The high temporal resolution available (~10 ms), the large range of frequencies observed (10-80 MHz & 120-240 MHz) and the large number of receiving stations (currently 52 across Europe) mean that LOFAR can observe the effects of the midlatitude ionosphere in an unprecedented level of detail.

The observational programme LT16_002 began in September 2021 and observations from the first 15 months of this programme are used to investigate ionospheric structures. A variety of patterns in the received signal intensity have been observed. Some of these appear to be similar to features reported previously, such as Spectral Caustics seen in solar observations (Koval et al., 2017) using the Nançay Decametric Array, as well as observations inferred from LOFAR of Travelling Ionospheric Disturbances (TIDs) at large- and medium-scales (Fallows et al., 2020), small scale TIDs (Boyde et al., 2022) and sporadic E (Wood et al., 2022). Other structures appear to be previously unreported. Collectively, we refer to these structures as Radio Alteration Features (RAFs).

In order to investigate the occurrence and origin of RAFs, 1092 hours of observations from LT16_002 were analysed. If the intensity of the received signal rose to 20% above the median value for the observation in a given hour then, within this study, this hour was classified as containing a RAF. RAFs were observed in 382 hours of observations. RAFs are primarily a night-time phenomenon and are more common in summer. They do not appear to have a statistically-significant relationship to geomagnetic activity as measured by a variety of geomagnetic indices, but there is some evidence that they are more common during times of enhanced solar activity or when a CME encounters the Earth.

Work on a measure of the strength of the RAFs is underway using the amplitude scintillation index S₄. New observations from LT16_002 mean that the database is continually expanding. Comparisons of the climatology of RAFs to the climatology of other features, such as TIDs, is planned to give an insight into the driving processes. The latest developments in this work will be reported.

References

Boyde, B., Wood, A. G., Dorrian, G. D., Fallows, R. A., Themens, D. R., et al. (2022). Lensing from small-scale travelling ionospheric disturbances observed using LOFAR. J. Space Weather Space Clim. 12, 34. https://doi.org/10.1051/swsc/2022030.

Fallows, R. A., et al. (2020), A LOFAR Observation of Ionospheric Scintillation from Simultaneous Medium- and Large-scale Travelling Ionospheric Disturbances, J. Space Weather Space Clim. doi.org/10.1051/swsc/2020010.

Koval, A., et al. (2017), Traveling ionospheric disturbances as huge natural lenses: Solar radio emission focusing effect, J. Geophys. Res. Space Physics, 122, 9092–9101, doi:10.1002/2017JA024080.

Wood, A. G., Dorrian, G. D., Boyde, B. and Fallows, R. A. (2022), Terrestrial drivers of rapidly changing plasma structures observed with the International LOFAR Telescope, 3rd URSI AT-AP-RASC.

How to cite: Wood, A., Dorrian, G., Boyde, B., Fallows, R., and Mevius, M.: Rapidly changing ionospheric structures inferred the by International LOFAR Telescope, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2700, https://doi.org/10.5194/egusphere-egu23-2700, 2023.

09:25–09:35

EGU23-3716

ECS

On-site presentation

Modeling the ionospheric delayed response to solar rotation period changes in EUV radiation

Rajesh Vaishnav, Christoph Jacobi, Erik Schmölter, Hanna Dühnen, Jens Berdermann, and Mihail Codrescu

The thermosphere-ionosphere system changes significantly on various temporal scales due to the forcings from solar and geomagnetic processes, and the lower atmosphere. The 27-day variation caused by solar rotation is one of the most important modulating factors in the ionosphere. A robust feature in this context is the ionospheric lag of about 1-2 days in ionospheric parameters such as total electron content (TEC) and F2 layer peak electron density with respect to solar variations at the 27-day solar rotation period. Here, the ionospheric TEC provided by the International GNSS Service (IGS) and the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model were used to understand the delayed ionospheric response and the underlying physics. The O/N₂ measurements from the imaging ultraviolet spectrograph Global-Scale Observations of the Limb and Disk (GOLD), the Global Ultraviolet Imager (GUVI), were also analyzed during the 2019-2021 period of low solar activity. The comparative study shows that the model successfully reproduces the delayed response of the ionosphere during low solar activity. The observed and modeled O/N₂ ratio was found to be positively correlated with the solar EUV proxy (GOLD Q_EUV), with a lag of about 2 days, indicating a contribution to the ionospheric lag in TEC.
Furthermore, the CTIPe model simulations show that the ionospheric time delay is significantly affected by various physical processes such as diffusion, photodissociation, solar and geomagnetic activities, and wave dynamics.

How to cite: Vaishnav, R., Jacobi, C., Schmölter, E., Dühnen, H., Berdermann, J., and Codrescu, M.: Modeling the ionospheric delayed response to solar rotation period changes in EUV radiation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3716, https://doi.org/10.5194/egusphere-egu23-3716, 2023.

09:35–09:45

EGU23-15390

ECS

On-site presentation

Modelling of Storm-Time Relative Total Electron Content using a Fully Connected Neural Network

Marjolijn Adolfs, Mainul Hoque, and Yuri Shprits

During geomagnetic storms the total electron content (TEC) can dramatically change compared to quiet-time conditions. Therefore, it is still a challenging task for ionospheric models to predict accurately during storm times. In this work, the relative TEC with respect to the preceding 27-day median TEC is predicted, during storm time for the European region (with longitudes 30°W–50°E and latitudes 32.5°N–70°N) using machine learning techniques. A fully connected neural network (NN) is proposed that uses the 27-day median TEC (referred to as median TEC), latitude, longitude, universal time, storm time, solar radio flux index F10.7, global storm index SYM-H and geomagnetic activity index Hp30 as inputs and the output of the network is the relative TEC. The model was trained with storm-time relative TEC data, computed with UQRG global ionosphere maps (GIMs), from the time period of 1998 until 2019 (2015 is excluded) and contains 365 storms. The model was tested with unseen storm data from 33 storm events during 2015 and 2020. The storm-time relative TEC model’s predictions showed the seasonal behavior of the storms including positive and negative storm phases during winter and summer, respectively, and a mixture of both phases was seen during equinoxes. The relative TEC was converted to the actual TEC, using the median TEC, and was compared to the Neustrelitz TEC model (NTCM) and a NN-based quiet-time TEC model. The storm model outperforms the NTCM by 1.87 TEC units (TECU) and the quiet-time model by 1.34 TECU during storm time.

How to cite: Adolfs, M., Hoque, M., and Shprits, Y.: Modelling of Storm-Time Relative Total Electron Content using a Fully Connected Neural Network, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15390, https://doi.org/10.5194/egusphere-egu23-15390, 2023.

09:45–09:55

EGU23-2039

On-site presentation

F30 is the most suitable solar activity proxies for foF2 at middle latitudes

Jan Laštovička

09:55–10:05

EGU23-8852

ECS

On-site presentation

Global ionospheric response to a periodic sequence of HSS/CIR events during the 2007-2008 solar minimum

Catalin Negrea, Costel Munteanu, and Marius Echim

We describe the global ionospheric impact of high-speed solar wind streams/corotating interaction regions (HSS/CIR), using a series of ten such events identified between December 1st 2007 and April 29th 2008. In the frequency domain they are characterized by the main spectral peaks corresponding to 27, 13.5, 9 and 6.75 days. The spectra of solar wind magnetic field, speed and proton density, as well as those of the geomagnetic indices AE and SYM-H are solely dominated by these features. By contrast, the ionospheric NmF2 and to a lesser extent the hmF2 spectra have a much more complex structure, with secondary peaks adding to or replacing the main ones. We argue that this is evidence of the nonlinear nature of the magnetosphere-ionosphere coupling, highlighted particularly in the NmF2 ionospheric response. Additionally, we show that hmF2 is more closely correlated than NmF2 to all parameters describing the solar wind and geomagnetic activity. Finally, the ionospheric response shows higher correlation with Bz than any other solar wind parameter, and higher with SYM-H than AE, indicating that for the low-frequency part of the spectrum, high-latitude Joule heating and particle precipitation play a secondary role to that of prompt penetration electric fields in dictating the ionospheric response to geomagnetic activity, in the case of this sequence of HSS/CIR events.

Results are also included in the paper:

Negrea et al. 2021 - Global Ionospheric Response to a Periodic Sequence of HSS/CIR Events During the 2007–2008 Solar Minimum (https://doi.org/10.1029/2020JA029071).

How to cite: Negrea, C., Munteanu, C., and Echim, M.: Global ionospheric response to a periodic sequence of HSS/CIR events during the 2007-2008 solar minimum, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8852, https://doi.org/10.5194/egusphere-egu23-8852, 2023.

10:05–10:15

EGU23-10750

On-site presentation

Study the July 7-8 2022 geomagnetic storm event using the MAGE simulation

Qian Wu, Wenbin Wang, Dong Lin, Liying Qian, Chaosong Huang, and Yongliang Zhang

Posters on site: Tue, 25 Apr, 14:00–15:45 | Hall X4

Chairpersons: Dalia Buresova, Jaroslav Urbar, Tobias Verhulst

Open Session on Ionosphere and Thermosphere -Poster Session

X4.266

EGU23-6633

ECS

Topside ionosphere effective plasma scale height characterization through CSES-01 satellite Langmuir Probes observations

Michael Pezzopane, Alessio Pignalberi, Igino Coco, Giuseppe Consolini, Giulia D'Angelo, Paola De Michelis, Fabio Giannattasio, Mirko Piersanti, and Roberta Tozzi

The topside ionosphere embraces the region extending from the F2-layer electron density peak to the overlying plasmasphere. In this region the electron density monotonically decreases at a vertical rate driven by the plasma scale height, which in turn depends on both the plasma chemical composition and the physical state. Since an accurate and thorough knowledge of the plasma chemical and physical properties at these altitudes is not available with the required spatial and temporal coverage, an effective plasma scale height is usually inferred from topside electron density measurements and used for empirical modelling purposes.

In this work, we aim at characterizing the effective plasma scale height (H₀) above the F2-layer peak through in-situ electron density (N_e) observations by Langmuir Probes (LPs) on-board the China Seismo-Electromagnetic Satellite (CSES-01). Additional information is given by the International Reference Ionosphere (IRI) model. CSES-01 is a sun-synchronous satellite flying with an orbital inclination of 97.4°, an altitude of ~500 km, and descending and ascending nodes are at ~14 local time (LT) and ~02 LT, respectively. Calibrated CSES-01 LPs N_e data recorded in the years 2019-2021 provides the information in the topside ionosphere, while IRI provides the N_e values at the F2-layer peak (NmF2) for the same time, latitude, and longitude sounded by CSES-01. These two N_e set of values are used as anchor points to infer H₀ through the topside representation given by the NeQuick model. By exploiting the CSES-01 dataset for the years 2019-2021 we deduced the global H₀ behavior for daytime (~14 LT) and nighttime (~02 LT) conditions, for low solar activity conditions. Results obtained with CSES-01 observations are compared and validated with corresponding ones provided by COSMIC-1 radio occultation measurements for similar diurnal and solar activity conditions.

How to cite: Pezzopane, M., Pignalberi, A., Coco, I., Consolini, G., D'Angelo, G., De Michelis, P., Giannattasio, F., Piersanti, M., and Tozzi, R.: Topside ionosphere effective plasma scale height characterization through CSES-01 satellite Langmuir Probes observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6633, https://doi.org/10.5194/egusphere-egu23-6633, 2023.

X4.267

EGU23-596

ECS

Swarm, FORMOSAT-7/COSMIC-2, and ICON ionospheric observations during the annular solar eclipse on 21 June 2020

Tzu-Hsun Kao and Jann-Yenq Liu

On 21 June 2020, an annular solar eclipse pass over Africa, Europe, and Asia. When the moon’s shadow sweeps, the solar radiation is blocked out and leads to weak photochemical effects and other variations on the ionosphere. The ion/electron temperature, density, and the ion vertical drift velocity measured by multi-satellites have been estimated and analyzed. EFI (Electric Field Instrument) onboard Swarm with a circular orbit of 88° inclination and 530 km altitude provides the data of electron temperature and density. IVM (ion velocity meter) onboard FORMOSAT-7/COSMIC-2 (F7/C2) with a circular orbit of 24° inclination and 550 km altitude supplies information on the ion temperature, density, and ion vertical drift velocity. IVM onboard Ionospheric Connection Explorer (ICON) with a circular orbit of 27° inclination and 579 km altitude offers the same parameters as F7/C2. On the event day, a total of 9 paths of those satellites passed through the greatest eclipse path, 6 from F7/C2, 2 from ICON, and 1 from Swarm. Referencing one-month data of each satellite path, both ion and electron temperature decrease about 500K after the maximum contact. Three of the four solar eclipse signatures in the ion density are observed, including pre-ascensions, major depressions, and sunset ascensions. Moreover, the ion drift velocity tends to be downward around the maximum contact. Detailed results will be presented and discussed.

How to cite: Kao, T.-H. and Liu, J.-Y.: Swarm, FORMOSAT-7/COSMIC-2, and ICON ionospheric observations during the annular solar eclipse on 21 June 2020, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-596, https://doi.org/10.5194/egusphere-egu23-596, 2023.

X4.268

EGU23-5590

Exploration of the divergent effects of CMEs on low Earth orbiting satellites – current status of the project ESPRIT

Sandro Krauss, Sofia Kroisz, Lukas Drescher, Manuel Scherf, Helmut Lammer, Manuela Temmer, and Andreas Strasser

With a view to the rising solar cycle 25 (maximum expected to be 2025/26) the solar activity level will steadily increase, which implies that the Earth’s atmosphere is expanding, and higher drag forces are acting on near-Earth satellites. To avoid earlier re-entries of satellite missions it is mandatory to monitor and at best accurately forecast extreme space weather conditions. We investigated different kinds of coronal mass ejections (CMEs) which had divergent effects on the trajectories of low Earth orbiting satellites. A special focus is given to the interaction of sequentially occurring CME events (e.g., 2021/11/03). So called multiple events lead to multiple field compressions and a capable to increase the severity of the impact on the near-Earth environment.

Furthermore, we investigated the predominant chemical composition of Earth atmosphere based on satellite observation from the TIMED satellite (SEE, SABER). Additionally, we explored identified diverging behavior of various CMEs by simulating the events with the Kompot code, a 1D first-principles hydrodynamic upper atmosphere model. We found that for some of the selected events the atmospheric exobase and density profile shows some significant expansion mainly based on the increased XUV flux from the Sun. However, we also found that the sole effect of the incident XUV flux might only partially explain NO production, and the structure of the upper atmosphere.

How to cite: Krauss, S., Kroisz, S., Drescher, L., Scherf, M., Lammer, H., Temmer, M., and Strasser, A.: Exploration of the divergent effects of CMEs on low Earth orbiting satellites – current status of the project ESPRIT, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5590, https://doi.org/10.5194/egusphere-egu23-5590, 2023.

X4.269

EGU23-8308

Doppler shifted auroral Lyman-alpha spectra observed by DMSP/SSUSI

Kan Liou, Larry Paxton, Yongliang Zhang, and Robert Schaefer

Proton auroras are produced by energetic protons that precipitate, undergo charged exchange, and subsequently emit hydrogen lines before they are ionized again. When viewed from space, the spectral shape of proton auroras is expected to shift to longer wavelengths (red shift) due to the Doppler effect. Reports on space-based observations of Doppler shift of hydrogen Lyman-alpha spectral line associated with auroral proton precipitation are still rare. The Special Sensor Ultraviolet Spectrographic Imager (SSUSI) on board the Defense Meteorological Satellite Program (DMSP) series is a line scanning imaging spectrograph covering the far ultraviolet (FUV) spectrum from ~112 to 185 nm with 160 spectral bins. Under the spectragraph mode, SSUSI is supposed to be able to provide information about proton auroral precipitation. Here we present results from our first attempt to extract Doppler shift of Lyman-alpha spectral line of Hydrogen from the SSUSI data. We show red-shifted Lyman-alpha spectra observed by SSUSI whenever the DMSP satellite traverses the auroral oval, especially during geomagnetic active time. In general, a larger red shift appears in the nightside than dayside oval crossing and in the equatorward than poleward half of the oval. These are generally consistent with in situ auroral particle observations reported previously. Thus DMSP/SSUSI provides an alternative means to monitoring the energetic of proton precipitation.

How to cite: Liou, K., Paxton, L., Zhang, Y., and Schaefer, R.: Doppler shifted auroral Lyman-alpha spectra observed by DMSP/SSUSI, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8308, https://doi.org/10.5194/egusphere-egu23-8308, 2023.

X4.270

EGU23-9013

PITHIA-NRF offers Trans-national access to European upper atmosphere research facilities

Ingemar Häggström and Maria Mihalikova

One of the objectives of the PITHIA-NRF project is to provide effective and convenient access to the best European research facilities for observations of the upper atmosphere. The individual PITHIA-NRF nodes provide access to key experimental and data processing facilities for studies and modeling of physical processes acting in the Earth’s plasmasphere, ionosphere and thermosphere. The facilities connected to the nodes are geographically distributed over Europe, as well as internationally, and their expertise and dedication span over a wide range of topics within the research area. This variety of expertise and techniques, all with the purpose of studying specific parts of the ionosphere-thermosphere-plasmasphere (ITP), allows for common ground and a platform for a better understanding of the many different complex couplings and interactions within ITP as well as between ITP and the magnetospheric/space environment.

The access to the nodes is organised through the Trans-National Access (TNA) programme and provides an opportunity for researchers and other users to execute and carry out their own projects at one of the twelve PITHIA-NRF research facilities. Users can request either physical access (a one-week visit at the node with support at the site) or remote access (one-month access from a distance with weekly support). Users with granted projects will learn how to work with the facilities during the complete access cycle, from setting up a campaign to the collection, analysis and finally exploitation of data with the help of tools and services provided by PITHIA-NRF via the e-science centre. There is also a possibility of virtual access - typically referring to access to data and digital tools. There are no restrictions to the number of simultaneous users, and no selective process is needed for this type of Access. PITHIA-NRF e-science centre is currently under development, and it will be offering more and more tools with time. Access to the TNA programme can be requested by scientific users from academia, Small and Medium Enterprises, large companies and public organizations by proposing a scientific project and applying through the PITHIA-NRF website: https://pithia-nrf.eu/

How to cite: Häggström, I. and Mihalikova, M.: PITHIA-NRF offers Trans-national access to European upper atmosphere research facilities, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9013, https://doi.org/10.5194/egusphere-egu23-9013, 2023.

X4.271

EGU23-10080

ECS

Three-dimensional modeling of barium cloud's expansion in the E and F regions: Applying for BROR mission.

Yoshihiro Yokoyama and Tima Sergienko

The chemical release at an ionospheric altitude allows us to investigate the plasma processes in the ionosphere-magnetosphere system. The numerical models of the expansion of the artificial plasma clouds produced by the chemical release have been developed. Previous works revealed that, for a barium release with no directional velocity in the uniform background, the neutral barium cloud expands radially, while the ionized barium (Ba+) cloud produced by photoionization of the neutral cloud expands into an elliptic structure along the direction of the magnetic field. And they also revealed that the background ionospheric and initial release conditions primarily affect the cloud’s behavior. Barium Release Optical and Radio rocket (BROR) mission plans to conduct several barium releases at different ionospheric altitudes between 120 and 180 km, which are much lower than past experiments, aiming to study small-scale processes and structure in the auroral ionosphere by means of an active modification of the ionosphere. Since the atmospheric composition of ion and neutral spices and their parameters vary significantly around the BROR target region, i.e., from the E region to the bottom of the F region, we took into these altitudinal differences in our model. We revealed that the altitudinal difference contributes significantly to the Ba+ cloud’s expansion, especially with no background and release velocity, producing a teardrop shape. We also found that the Ba+ cloud at lower altitudes expands slowly, confining to a relatively small area due to the higher collision frequency. In comparison, the Ba+ cloud at a higher altitude stretches faster along the magnetic field and ends up with larger radii due to the lower collision frequency and higher diffusion rate. In this presentation, we show numerical results for the different release conditions at several altitudes in the E and F region and discuss the effects of different release conditions at various altitudes.

How to cite: Yokoyama, Y. and Sergienko, T.: Three-dimensional modeling of barium cloud's expansion in the E and F regions: Applying for BROR mission., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10080, https://doi.org/10.5194/egusphere-egu23-10080, 2023.

X4.272

EGU23-17033

Global Ion Density Distributions Observed by Advanced Ionospheric Probe Onboard FORMOSAT-5 Satellite

Chi-Kuang Chao

X4.273

EGU23-597

ECS

Hemispheric Asymmetries in the Ionospheric Total Electron Content during 1999-2019

Yu-Chi Chang and Jann-Yenq Liu

This paper studies the hemispheric asymmetry of the total electron content (TEC) by means of the Global Ionosphere Map (GIM), which has been routinely publishing every 2 hours by the Center for Orbit Determination in Europe (CODE) during 1999-2019. The study period including the solar cycles 23 and 24 allows us globally uniformly examine the ionospheric asymmetry phenomenon of the GIM TEC in the different solar activities. At each time point, summations of the GIM TEC at low-, mid-, and high-latitude in the northern and southern hemispheres are computed. Results reveal the maximum summations of the GIM TEC occurring in April or November and the minimum summations of the GIM TEC occurring in July, which indicates the extreme TEC values in each year are not at the equinox or solstice. We compare the sums of the two hemispheres in various local times, months, and solar activities. By computing the annual magnitude of the asymmetry phenomenon, it is found that the asymmetric phenomenon is more prominent during the low solar activity, although its fluctuation is proportional to the F10.7 index. We further study the asymmetry phenomenon in various latitudes and find the latitudes with prominent signatures.

How to cite: Chang, Y.-C. and Liu, J.-Y.: Hemispheric Asymmetries in the Ionospheric Total Electron Content during 1999-2019, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-597, https://doi.org/10.5194/egusphere-egu23-597, 2023.

X4.274

EGU23-685

ECS

Ground and Ionospheric Signatures of Solar Wind-Magnetosphere Interaction at Mid-Latitudes

Ezgi Gülay, Zerefşan Kaymaz, and Emine Ceren Kalafatoğlu Eyigüler

As we enter the increasing solar activity epoch, the space weather phenomena and predictions become crucially important to avoid the effects on our lives and technology which is becoming more space-dependent every day. One of the key issues in space weather is to determine the worldwide signatures of the solar wind-magnetosphere-ionosphere coupling. While the response of the high and low latitude regions on Earth to the space weather phenomena is well established, the signatures at the mid-latitudes comparatively are less explored. Being farther from both the auroral and the equatorial latitudes, mid-latitude signatures of the solar wind-magnetosphere interaction can be more complex and may not be so straightforward. In this study, the effects of the geomagnetic activity are investigated using observational tools which are unique to its geographical region, north-west Turkey. Dynasonde radar measurements (Dynasonde at ITU Campus, 41°N, 29°E), magnetotelluric measurements of ground electric field (Magnetotelluric station at Bozcaada, 39.5°N, 26°E), and geomagnetic field variations (Geomagnetic observatory at Iznik, 40.43°N, 29.72°E) are combined to obtain a global perspective of the space weather effects in this mid-latitude region. Magnetically active periods were determined using Dst index and the variations in the corresponding ionospheric electron density and the geomagnetically induced currents (GICs) were analyzed based on the case studies as well as statistical tools. More than 20 indicators such as differences in the fields, extreme values, averages, and storm durations were analyzed and their relations to magnetic storms as well as solar wind and interplanetary magnetic field (IMF) connections were studied. GICs were investigated based on the variations in the horizontal magnetic field. The dependence on the magnetic storm phases was revealed. One of the most intriguing results from both case studies and statistical analysis is that stronger GICs were found in our region during the recovery phase of the geomagnetic storms. The electron density variations indicated both positive and negative effects during the storms. The magnitudes of the variations for both GICs and electron density variations were determined. While the case studies indicate close relations with geomagnetic indices, solar wind, and IMF variations, statistical results resulted in small correlation coefficients. This emphasizes and further indicates the importance of the statistical indicator that is used in the correlation analysis. In this presentation, solar wind-magnetosphere connection to the ionosphere and to the ground will be discussed in view of our findings. It is believed that these results will improve our understanding of the cause-and-effect of the space weather phenomena at mid-latitudes while at the same time, it will give support to global space weather modeling studies.

How to cite: Gülay, E., Kaymaz, Z., and Kalafatoğlu Eyigüler, E. C.: Ground and Ionospheric Signatures of Solar Wind-Magnetosphere Interaction at Mid-Latitudes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-685, https://doi.org/10.5194/egusphere-egu23-685, 2023.

X4.275

EGU23-6707

Multiinstrumental observations of traveling ionospheric disturbances over Europe

Dalia Buresova, Sergii V. Panasenko, Kateryna D. Aksonova, Oleksandr V. Bogomaz, Taras G. Zhivolup, and Alexander V. Koloskov

The paper presents results of the analysis of the TID activity and changes in the regular ionospheric variability observed over central and eastern Europe during geomagnetically quiet days, and during CME and CIR/HSSS-related storms. We analyzed main ionospheric parameters retrieved from manually scaled ionograms obtained at several central and eastern European locations and incoherent scatter radar data (Kharkiv, Ukraina). Large scale traveling ionospheric disturbance (LSTIDs) are thought to be mostly originated in the auroral zone in consequence of increased geomagnetic activity. Although there have been numerous studies of TIDs, current knowledge is often based on observing only limited set of parameters and two-dimensional characteristics (for example, total electron content by GNSS receivers or airglow brightness by all-sky imagers). Incoherent scatter technique enables simultaneous studies of altitudinal characteristics of TIDs in several parameters like electron density, electron and ion temperature and plasma drift, thus providing important information needed to investigate TIDs, their propagation and consider probable association of TIDs with their sources. This technique also yields all components of wave vector, provided that the radar has the ability to operate in multi-beam mode. In order to obtain quantitative information on the likeliness and morphology of the passage of LSTIDs over Europe at about 40 events were examined lasting between 8 and 24 hours each. In this paper we focused mainly on a couple of geomagnetic disturbances (depending on the incoherent scatter radar data availability). Most of the observed storm-related TIDs had periods of 60-180 min (LSTIDs). During the analyzed storms we also observed extraordinary spreads and plasma bubbles at the F region heights.

How to cite: Buresova, D., Panasenko, S. V., D. Aksonova, K., Bogomaz, O. V., Zhivolup, T. G., and Koloskov, A. V.: Multiinstrumental observations of traveling ionospheric disturbances over Europe, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6707, https://doi.org/10.5194/egusphere-egu23-6707, 2023.

X4.276

EGU23-13577

ECS

Using convoluted distributions to infer auroral brightness during sunlit conditions

Jens Christian Hessen, Jone Peter Reistad, and Karl Magnus Laundal

Sunlight makes it difficult to measure the aurora. We use data obtained by the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) onboard the Defense Meteorological Satellite Program’s (DMSP) F16-19 satellites to quantify the auroral intensities during sunlit conditions. We use Environmental Disk Radiance (EDR) Aurora data product from the SSUSI-team, where the dayglow is already subtracted. The error in the dayglow-subtraction is proportional to the strength of the dayglow and represents an uncertainty in the observations. We characterize the auroral intensity and the dayglow part of the signal by combining multiple observations during similar solar illumination, and magnetic local time/latitude. By fitting convolutions of symmetric (dayglow-error) and fat-tailed distributions (aurora) on data from many years, it might be possible to separate the signal from the aurora. By comparing this to the regular methods of estimating auroral intensity (mean/median) we will assess the usefulness and importance of this method. We examine the validity of our method by evaluating the fits of the convoluted distributions.

How to cite: Hessen, J. C., Reistad, J. P., and Laundal, K. M.: Using convoluted distributions to infer auroral brightness during sunlit conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13577, https://doi.org/10.5194/egusphere-egu23-13577, 2023.

X4.277

EGU23-16331

ECS

Total Electron Content evolution during the 27 February 2014 storm over the Iberian Peninsula and Northern Africa

Saioa A. Campuzano, Yenca Migoya-Orué, Sandro M. Radicella, Fernando Delgado-Gómez, Miguel Herraiz, and Gracia Rodríguez-Caderot

In this work Total Electron Content (TEC) during the moderate geomagnetic storm of 27 February 2014 over the Iberian Peninsula and Northern Africa is analysed. The data used are coming from GNSS derived TEC and ROTI from several receiver stations from Spain, Portugal and Morocco. Maps of TEC are developed to study its evolution before, during and some days after the main phase of the storm. This study shows that before the storm, i.e. during quiet geomagnetic conditions, a northern crest of the Equatorial Ionosphere Anomaly (EIA) is located in Western North Africa with low gradients and values of TEC. During the main period of the storm, this northern crest of the EIA is also located in the Western North Africa with larger gradients that affect the southern part of the Iberian Peninsula. These gradients are present both in latitude and longitude. They are observed exclusively over this region but not seen in the rest of Southern Europe. In addition, increased values of ROTI from GNSS stations located in Southern Spain are also found during the storm, but not observed northwards and eastwards of that region. Since the Iberian Peninsula is located in a mid-latitude area not expected to be influenced by the EIA, these findings seem to indicate that the Southern part of the Peninsula could be influenced by the EIA during disturbed geomagnetic conditions.

How to cite: Campuzano, S. A., Migoya-Orué, Y., Radicella, S. M., Delgado-Gómez, F., Herraiz, M., and Rodríguez-Caderot, G.: Total Electron Content evolution during the 27 February 2014 storm over the Iberian Peninsula and Northern Africa, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16331, https://doi.org/10.5194/egusphere-egu23-16331, 2023.

Open Session on Ionosphere and Thermosphere

Posters virtual: Tue, 25 Apr, 14:00–15:45 | vHall ST/PS

Chairpersons: Jaroslav Urbar, Tobias Verhulst, Dalia Buresova

Open Session on Ionosphere and Thermosphere - Posters virtual

vSP.3

EGU23-3911

Atmospheric gravity waves generated by solar wind high-speed stream Alfvén waves

Paul Prikryl, David R. Themens, Jaroslav Chum, Shibaji Chakraborty, Robert G. Gillies, and James M. Weygand

Solar wind Alfvén waves in high-speed streams from coronal holes modulate dayside ionospheric convection and currents, including auroral electrojets [1]. They generate large- to medium-scale atmospheric gravity waves (AGWs) propagating globally from sources in the lower thermosphere both upward and downward [2,3]. In the upper atmosphere, the AGWs drive traveling ionospheric disturbances (TIDs) observed by the Super Dual Auroral Radar Network (SuperDARN), Poker Flat Incoherent Scatter Radar (PFISR), and the GNSS total electron content (TEC) mapping technique. The horizontal equivalent ionospheric currents are estimated from the ground-based magnetometer data using an inversion technique. In the lower atmosphere, the equatorward propagating AGWs with attenuated amplitudes can be amplified upon over-reflection in the troposphere. They can release conditional symmetric instability leading to slantwise convection, latent heat release and intensification of extratropical cyclones [4,5], which in turn are a source of AGWs/TIDs. Southeastward propagating TIDs that originate from cold fronts of intensifying extratropical cyclones are observed in the detrended TEC maps, and by the multipoint and multifrequency continuous Doppler sounders in Czechia. Ray tracing AGWs in a model atmosphere supports the observations.

[1] Prikryl P., et al., Ann. Geophys., 40, 619–639, 2022. doi.org/10.5194/angeo-40-619-2022
[2] Mayr H.G., et al., Space Sci. Rev. 54, 297–375, 1990. doi:10.1007/BF00177800
[3] Prikryl, P., et al., Ann. Geophys. 23, 401–417, 2005. doi.org/10.5194/angeo-23-401-2005
[4] Prikryl P., et al., Ann. Geophys. 27, 31–57, 2009. doi:10.5194/angeo-27-31-2009
[5] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 171, 94–10, 2018. doi:10.1016/j.jastp.2017.07.023

How to cite: Prikryl, P., Themens, D. R., Chum, J., Chakraborty, S., Gillies, R. G., and Weygand, J. M.: Atmospheric gravity waves generated by solar wind high-speed stream Alfvén waves, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3911, https://doi.org/10.5194/egusphere-egu23-3911, 2023.