Moshe Godfrey Mosotho, Du Toit Roelf Strauss, S. Böttcher, C. Diedericks
The radiation environment over the African continent, at aviation altitudes, remains mostly uncharacterized and unregulated. In this paper we present initial measurements made by a newly developed active dosimeter on-board long-haul flights between South Africa and Germany. Based on these initial tests, we believe that this low-cost and open-source dosimeter is suitable for continued operation over the Africa continent and can provide valuable long-term measurements to test dosimteric models and inform aviation policy.
{"title":"The radiation environment over the African continent at aviation altitudes: First results of the RPiRENA-based dosimeter","authors":"Moshe Godfrey Mosotho, Du Toit Roelf Strauss, S. Böttcher, C. Diedericks","doi":"10.1051/swsc/2023007","DOIUrl":"https://doi.org/10.1051/swsc/2023007","url":null,"abstract":"The radiation environment over the African continent, at aviation altitudes, remains mostly uncharacterized and unregulated. In this paper we present initial measurements made by a newly developed active dosimeter on-board long-haul flights between South Africa and Germany. Based on these initial tests, we believe that this low-cost and open-source dosimeter is suitable for continued operation over the Africa continent and can provide valuable long-term measurements to test dosimteric models and inform aviation policy.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43822692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Anthony Massoud, F. Rodrigues, S. Shidler
We introduce the implementation of a global climatological model of the equatorial ionospheric F-region zonal drifts (EZDrifts) that is made available to the public. The model uses the analytic description of the zonal plasma drifts presented by Haerendel et al. (1992) and is driven by climatological models of the ionosphere and thermosphere under a realistic geomagnetic field configuration. EZDrifts is an expansion of the model of the zonal drifts first presented by Shidler and Rodrigues (2021) which was only valid for the Jicamarca longitude sector and two specific solar flux conditions. EZDrifts now uses vertical equatorial plasma drifts from the Scherliess and Fejer (1999) model which allows it to provide zonal drifts for any day of the year, longitude and solar flux condition. We show that the model can reproduce the main results of the Shidler and Rodrigues (2021) model for the Peruvian sector. We also illustrate an application of EZDrifts by presenting and discussing longitudinal variabilities produced by the model. We show that the model predicts longitudinal variations in the reversal times of the drifts that are in good agreement with observations made by C/NOFS. EZDrifts also predicts longitudinal variations in the magnitude of the drifts that can be identified in the June solstice observations made by C/NOFS. We also point out data-model differences observed during Equinox and December solstice. Finally, we explain that the longitudinal variations in the zonal plasma drifts are caused by longitudinal variations in the latitude of the magnetic equator and, consequently, in the wind dynamo contributing to the resulting drifts. EZDrifts is distributed to the community through a public repository and can be used in applications requiring an estimate of the overall behavior of the equatorial zonal drifts.
{"title":"A height-dependent climatological model of the Equatorial ionospheric Zonal plasma Drifts (EZDrifts): Description and application to an analysis of the longitudinal variations of the zonal drifts","authors":"Alexander Anthony Massoud, F. Rodrigues, S. Shidler","doi":"10.1051/swsc/2023006","DOIUrl":"https://doi.org/10.1051/swsc/2023006","url":null,"abstract":"We introduce the implementation of a global climatological model of the equatorial ionospheric F-region zonal drifts (EZDrifts) that is made available to the public. The model uses the analytic description of the zonal plasma drifts presented by Haerendel et al. (1992) and is driven by climatological models of the ionosphere and thermosphere under a realistic geomagnetic field configuration. EZDrifts is an expansion of the model of the zonal drifts first presented by Shidler and Rodrigues (2021) which was only valid for the Jicamarca longitude sector and two specific solar flux conditions. EZDrifts now uses vertical equatorial plasma drifts from the Scherliess and Fejer (1999) model which allows it to provide zonal drifts for any day of the year, longitude and solar flux condition. We show that the model can reproduce the main results of the Shidler and Rodrigues (2021) model for the Peruvian sector. We also illustrate an application of EZDrifts by presenting and discussing longitudinal variabilities produced by the model. We show that the model predicts longitudinal variations in the reversal times of the drifts that are in good agreement with observations made by C/NOFS. EZDrifts also predicts longitudinal variations in the magnitude of the drifts that can be identified in the June solstice observations made by C/NOFS. We also point out data-model differences observed during Equinox and December solstice. Finally, we explain that the longitudinal variations in the zonal plasma drifts are caused by longitudinal variations in the latitude of the magnetic equator and, consequently, in the wind dynamo contributing to the resulting drifts. EZDrifts is distributed to the community through a public repository and can be used in applications requiring an estimate of the overall behavior of the equatorial zonal drifts.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49070329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spatial correlations of total electron content (TEC) variability are compared among two SAMI3 model runs and Jet Propulsion Laboratory Global Ionospheric Maps (JPL/GIM). Individual monthly correlation maps are constructed with Equatorial reference points at 12 evenly spaced longitudes and 12 universal times. TEC composite correlations (TCCs) are then calculated by averaging the individual maps, shifted zonally to synchronize local time. The TCC structures are quantified using Gaussian fits in the zonal and meridional directions. A non-zero large-scale “base correlation” is found in all three datasets for 2014, a year with high solar activity. Higher base correlations generally occur in the SAMI3 runs than in JPL/GIM. The SAMI3 run driven with climatological neutral fields shows higher correlations than the run driven with neutrals from a Whole Atmosphere Community Climate Model and ionosphere extension (WACCM-X) simulation. Base correlation values strongly correlate with monthly F10.7 standard deviations. Empirical Orthogonal Function (EOF) analyses confirm the large-scale correlations are usually, although not always, related to solar forcing. Strong correlations between the Ap index and EOF modes are also observed, consistent with geomagnetic forcing of the TEC field. The width of the correlation structures are also examined, and these vary considerably with local time, month, and dataset. Off-Equator conjugate point correlations are also calculated from each dataset and variations with month and local time are analyzed. Analysis of TCCs for 2010, a year with low solar activity, shows that base correlations as well as correlations of the first EOF mode with F10.7 are generally weaker than in 2014.
{"title":"Low latitude monthly total electron content composite correlations","authors":"D. Allen, D. Hodyss, V. Forsythe, S. McDonald","doi":"10.1051/swsc/2023005","DOIUrl":"https://doi.org/10.1051/swsc/2023005","url":null,"abstract":"Spatial correlations of total electron content (TEC) variability are compared among two SAMI3 model runs and Jet Propulsion Laboratory Global Ionospheric Maps (JPL/GIM). Individual monthly correlation maps are constructed with Equatorial reference points at 12 evenly spaced longitudes and 12 universal times. TEC composite correlations (TCCs) are then calculated by averaging the individual maps, shifted zonally to synchronize local time. The TCC structures are quantified using Gaussian fits in the zonal and meridional directions. A non-zero large-scale “base correlation” is found in all three datasets for 2014, a year with high solar activity. Higher base correlations generally occur in the SAMI3 runs than in JPL/GIM. The SAMI3 run driven with climatological neutral fields shows higher correlations than the run driven with neutrals from a Whole Atmosphere Community Climate Model and ionosphere extension (WACCM-X) simulation. Base correlation values strongly correlate with monthly F10.7 standard deviations. Empirical Orthogonal Function (EOF) analyses confirm the large-scale correlations are usually, although not always, related to solar forcing. Strong correlations between the Ap index and EOF modes are also observed, consistent with geomagnetic forcing of the TEC field. The width of the correlation structures are also examined, and these vary considerably with local time, month, and dataset. Off-Equator conjugate point correlations are also calculated from each dataset and variations with month and local time are analyzed. Analysis of TCCs for 2010, a year with low solar activity, shows that base correlations as well as correlations of the first EOF mode with F10.7 are generally weaker than in 2014.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47033740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Malone‐Leigh, J. Campanyà, P. Gallagher, Maik Neukirch, C. Hogg, J. Hodgson
Geomagnetically induced currents (GIC) driven by geoelectric fields pose a hazard to ground-based infrastructure, such as power grids and pipelines. Here, a new method is presented for modelling geoelectric fields in near real time, with the aim of providing valuable information to help mitigate the impact of GIC. The method uses magnetic field measurements from the Magnetometer Network of Ireland (MagIE; www.magie.ie), interpolates the geomagnetic field variations between magnetometers using spherical elementary current systems (SECS), and estimates the local electric field using a high density (< 40 km) network of magnetotelluric transfer functions (MT-TF) encompassing the island. The model was optimised to work in near real time, with a correction curve applied to the geoelectric field time series. This approach was successfully validated with measured electric fields at four sites for a number of geomagnetic storms, providing accurate electric fields up to a 1-minute delay from real time, with high coherence (0.70 – 0.85) and signal-to-noise ratio (SNR; 3.2 – 6.5) relative to measured electric field validation time series. This was comparable to a standard non real-time geoelectric field model (coherence = 0.80 – 0.89 and SNR = 4.0 – 7.0). The impact of galvanic distortion on the model was also briefly evaluated, with a galvanic distortion correction leading to a more homogeneous representation of the direction of the electric field, at a regional scale.
{"title":"Nowcasting Geoelectric Fields in Ireland using Magnetotelluric Transfer Functions.","authors":"J. Malone‐Leigh, J. Campanyà, P. Gallagher, Maik Neukirch, C. Hogg, J. Hodgson","doi":"10.1051/swsc/2023004","DOIUrl":"https://doi.org/10.1051/swsc/2023004","url":null,"abstract":"Geomagnetically induced currents (GIC) driven by geoelectric fields pose a hazard to ground-based infrastructure, such as power grids and pipelines. Here, a new method is presented for modelling geoelectric fields in near real time, with the aim of providing valuable information to help mitigate the impact of GIC. The method uses magnetic field measurements from the Magnetometer Network of Ireland (MagIE; www.magie.ie), interpolates the geomagnetic field variations between magnetometers using spherical elementary current systems (SECS), and estimates the local electric field using a high density (< 40 km) network of magnetotelluric transfer functions (MT-TF) encompassing the island. The model was optimised to work in near real time, with a correction curve applied to the geoelectric field time series. This approach was successfully validated with measured electric fields at four sites for a number of geomagnetic storms, providing accurate electric fields up to a 1-minute delay from real time, with high coherence (0.70 – 0.85) and signal-to-noise ratio (SNR; 3.2 – 6.5) relative to measured electric field validation time series. This was comparable to a standard non real-time geoelectric field model (coherence = 0.80 – 0.89 and SNR = 4.0 – 7.0). The\u0000impact of galvanic distortion on the model was also briefly evaluated, with a galvanic distortion\u0000correction leading to a more homogeneous representation of the direction of the electric field, at a\u0000regional scale.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42408498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alejandro Jesús, Pérez Aparicio, V. Carrasco, M. C. Gallego, J. Vaquero
The Madrid Astronomical Observatory implemented a solar observation program from 1876 to 1986. In addition to sunspots, the observers at this observatory recorded other solar features such as prominences. In this work, we have consulted the documentary sources of the Madrid Astronomical Observatory (the information is not digitally available), digitized the records of the observers on the annual number of prominences, and constructed a homogeneous series of the total and hemispheric annual number of prominences with heights of 25’’ and more for the period 1906 – 1957. To evaluate the quality of the data and assess their potential, we have compared the Madrid prominence series with the number of prominences recorded by the Astronomical Observatory of the University of Coimbra and other time series such as the sunspot number index, solar radio flux at 10.7 cm, and sunspot areas. We have also analyzed the hemispheric prominence numbers and the asymmetry index. We obtained the strongest correlation between Madrid and Coimbra prominence series (r = 0.7), whereas the correlations between Madrid prominence series and the other solar activity time series are similar (r ≈ 0.6). In addition, we found that the correlation coefficient between the Madrid prominence series and the sunspot number is lower than that from Coimbra prominence series and the sunspot number. We suggest that these differences are a consequence of the way prominences were counted in the Madrid Astronomical Observatory.
{"title":"Rediscovering the observations of solar prominences from 1906 to 1957 recorded at the Madrid Astronomical Observatory","authors":"Alejandro Jesús, Pérez Aparicio, V. Carrasco, M. C. Gallego, J. Vaquero","doi":"10.1051/swsc/2023003","DOIUrl":"https://doi.org/10.1051/swsc/2023003","url":null,"abstract":"The Madrid Astronomical Observatory implemented a solar observation program from 1876 to 1986. In addition to sunspots, the observers at this observatory recorded other solar features such as prominences. In this work, we have consulted the documentary sources of the Madrid Astronomical Observatory (the information is not digitally available), digitized the records of the observers on the annual number of prominences, and constructed a homogeneous series of the total and hemispheric annual number of prominences with heights of 25’’ and more for the period 1906 – 1957. To evaluate the quality of the data and assess their potential, we have compared the Madrid prominence series with the number of prominences recorded by the Astronomical Observatory of the University of Coimbra and other time series such as the sunspot number index, solar radio flux at 10.7 cm, and sunspot areas. We have also analyzed the hemispheric prominence numbers and the asymmetry index. We obtained the strongest correlation between Madrid and Coimbra prominence series (r = 0.7), whereas the correlations between Madrid prominence series and the other solar activity time series are similar (r ≈ 0.6). In addition, we found that the correlation coefficient between the Madrid prominence series and the sunspot number is lower than that from Coimbra prominence series and the sunspot number. We suggest that these differences are a consequence of the way prominences were counted in the Madrid Astronomical Observatory.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45035691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study we make use of the Swarm counter-rotation constellation for estimating the typical scale length of the post-sunset equatorial plasma bubbles (EPBs) along fluxtubes. The close approaches between Swarm spacecraft near the equator occurred in September and October 2021, covering magnetic local time from 19:00 to 23:00, which is favorable for the occurrence of EPBs. It is the first time to show the quasi-simultaneously samplings by Swarm A/C and B of the same fluxtube but at different altitudes, and the observations frequently reveal plasma density depletions only at one spacecraft altitude, confirming that EPBs extend only over finite parts of the fluxtube. Based on a statistical analysis of double and single EPB detections on the same fluxtube, our results imply the typical field-aligned scale length of the depletion structures associated with EPBs of the order of 550 km. Our detections are from the lower part of the depleted fluxtubes, and they coincide well with the latitudes of the equatorial ionization anomaly. In the upper part of the fluxtube near the magnetic equator, our estimation technique does not work well because of too large field-aligned spacecraft separation of the Swarm satellites.
{"title":"Field-aligned scale length of depleted structures associated with post-sunset equatorial plasma bubbles","authors":"C. Xiong, H. Lühr","doi":"10.1051/swsc/2023002","DOIUrl":"https://doi.org/10.1051/swsc/2023002","url":null,"abstract":"In this study we make use of the Swarm counter-rotation constellation for estimating the typical scale length of the post-sunset equatorial plasma bubbles (EPBs) along fluxtubes. The close approaches between Swarm spacecraft near the equator occurred in September and October 2021, covering magnetic local time from 19:00 to 23:00, which is favorable for the occurrence of EPBs. It is the first time to show the quasi-simultaneously samplings by Swarm A/C and B of the same fluxtube but at different altitudes, and the observations frequently reveal plasma density depletions only at one spacecraft altitude, confirming that EPBs extend only over finite parts of the fluxtube. Based on a statistical analysis of double and single EPB detections on the same fluxtube, our results imply the typical field-aligned scale length of the depletion structures associated with EPBs of the order of 550 km. Our detections are from the lower part of the depleted fluxtubes, and they coincide well with the latitudes of the equatorial ionization anomaly. In the upper part of the fluxtube near the magnetic equator, our estimation technique does not work well because of too large field-aligned spacecraft separation of the Swarm satellites.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44554571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Ruth McKee, P. Cilliers, S. Lotz, C. Monstein
Solar radio bursts have been associated with a number of disruptions in avionic systems. The objective of this work is to develop solar radio burst interference thresholds which account for the technical specifications of aviation related instrumentation, instrument operating frequencies as well as industry stipulated error tolerances. Solar radio bursts are suggested to be potentially hazardous when exceeding these calculated thresholds. Particular attention is paid to the radio altimeter, an important component in aviation safety. The thresholds suggested in this work for VHF communication, GPS navigation receivers and radio altimeter frequencies are; 102 , 103 and 104 sfu respectively. Solar radio burst interference (for solar radio bursts above 104 sfu) is shown to result in large errors (64-251 m) in the altitude estimates for the Frequency Modulated Continuous Waves (FMCW) radio altimeter simulated in this work.
{"title":"The effects of Solar radio bursts on frequency bands utilised by the aviation industry in Sub-Saharan Africa.","authors":"Sarah Ruth McKee, P. Cilliers, S. Lotz, C. Monstein","doi":"10.1051/swsc/2023001","DOIUrl":"https://doi.org/10.1051/swsc/2023001","url":null,"abstract":"Solar radio bursts have been associated with a number of disruptions in avionic systems. The\u0000objective of this work is to develop solar radio burst interference thresholds which account for\u0000the technical specifications of aviation related instrumentation, instrument operating frequencies\u0000as well as industry stipulated error tolerances. Solar radio bursts are suggested to be potentially\u0000hazardous when exceeding these calculated thresholds. Particular attention is paid to the radio\u0000altimeter, an important component in aviation safety. The thresholds suggested in this work for\u0000VHF communication, GPS navigation receivers and radio altimeter frequencies are; 102 , 103 and\u0000104 sfu respectively. Solar radio burst interference (for solar radio bursts above 104 sfu) is shown to\u0000result in large errors (64-251 m) in the altitude estimates for the Frequency Modulated Continuous\u0000Waves (FMCW) radio altimeter simulated in this work.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44934956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Grandin, Thijs Luttikhuis, M. Battarbee, G. Cozzani, Hongyang Zhou, L. Turc, Y. Pfau‐Kempf, H. George, K. Horaites, E. Gordeev, U. Ganse, Konstantinos E. Papadakis, M. Alho, F. Tesema, J. Suni, M. Dubart, V. Tarvus, M. Palmroth
The precipitation of charged particles from the magnetosphere into the ionosphere is one of the crucial coupling mechanisms between these two regions of geospace and is associated with multiple space weather effects, such as global navigation satellite system signal disruption and geomagnetically induced currents at ground level. While precipitating particle fluxes have been measured by numerous spacecraft missions over the past decades, it often remains difficult to obtain global precipitation patterns with a good time resolution during a substorm. Numerical simulations can help to bridge this gap and improve the understanding of mechanisms leading to particle precipitation at high latitudes through the global view they offer on the near-Earth space system. We present the first results on auroral (0.5–50 keV) proton precipitation within a 3-dimensional simulation of the Vlasiator hybrid-Vlasov model. The run is driven by southward interplanetary magnetic field conditions with constant solar wind parameters. We find that, on the dayside, cusp proton precipitation exhibits the expected energy–latitude dispersion and takes place in the form of successive bursts associated with the transit of flux transfer events formed through dayside magnetopause reconnection. On the nightside, the precipitation takes place within the expected range of geomagnetic latitudes, and it appears clearly that the precipitating particle injection is taking place within a narrow magnetic local time span, associated with fast Earthward plasma flows in the near-Earth magnetotail. Finally, the simulated precipitating fluxes are compared to observations from Defense Meteorological Satellite Program spacecraft during driving conditions similar to those in the simulation and are found to be in good agreement with the measurements.
{"title":"First 3D hybrid-Vlasov global simulation of auroral proton precipitation and comparison with satellite observations","authors":"M. Grandin, Thijs Luttikhuis, M. Battarbee, G. Cozzani, Hongyang Zhou, L. Turc, Y. Pfau‐Kempf, H. George, K. Horaites, E. Gordeev, U. Ganse, Konstantinos E. Papadakis, M. Alho, F. Tesema, J. Suni, M. Dubart, V. Tarvus, M. Palmroth","doi":"10.1051/swsc/2023017","DOIUrl":"https://doi.org/10.1051/swsc/2023017","url":null,"abstract":"The precipitation of charged particles from the magnetosphere into the ionosphere is one of the crucial coupling mechanisms between these two regions of geospace and is associated with multiple space weather effects, such as global navigation satellite system signal disruption and geomagnetically induced currents at ground level. While precipitating particle fluxes have been measured by numerous spacecraft missions over the past decades, it often remains difficult to obtain global precipitation patterns with a good time resolution during a substorm. Numerical simulations can help to bridge this gap and improve the understanding of mechanisms leading to particle precipitation at high latitudes through the global view they offer on the near-Earth space system. We present the first results on auroral (0.5–50 keV) proton precipitation within a 3-dimensional simulation of the Vlasiator hybrid-Vlasov model. The run is driven by southward interplanetary magnetic field conditions with constant solar wind parameters. We find that, on the dayside, cusp proton precipitation exhibits the expected energy–latitude dispersion and takes place in the form of successive bursts associated with the transit of flux transfer events formed through dayside magnetopause reconnection. On the nightside, the precipitation takes place within the expected range of geomagnetic latitudes, and it appears clearly that the precipitating particle injection is taking place within a narrow magnetic local time span, associated with fast Earthward plasma flows in the near-Earth magnetotail. Finally, the simulated precipitating fluxes are compared to observations from Defense Meteorological Satellite Program spacecraft during driving conditions similar to those in the simulation and are found to be in good agreement with the measurements.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45410358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Nedal, Kamen Kozarev, Nestor Arsenov, Peijin Zhang
Solar energetic particles are mainly protons and originate from the Sun during solar flares or coronal shock waves. Forecasting the Solar Energetic Protons (SEP) flux is critical for several operational sectors, such as communication and navigation systems, space exploration missions, and aviation flights, as the hazardous radiation may endanger astronauts’, aviation crew, and passengers’ health, the delicate electronic components of satellites, space stations, and ground power stations. Therefore, the prediction of the SEP flux is of high importance to our lives and may help mitigate the negative impacts of one of the serious space weather transient phenomena on the near-Earth space environment. Numerous SEP prediction models are being developed with a variety of approaches, such as empirical models, probabilistic models, physics-based models, and AI-based models. In this work, we use the bidirectional long short-term memory (BiLSTM) neural network model architecture to train SEP forecasting models for three standard integral GOES channels (>10 MeV, >30 MeV, >60 MeV) with three forecast windows (1-day, 2-day, and 3-day ahead) based on daily data obtained from the OMNIWeb database from 1976 to 2019. As the SEP variability is modulated by the solar cycle, we select input parameters that capture the short-term, typically within a span of a few hours, and long-term, typically spanning several days, fluctuations in solar activity. We take the F10.7 index, the sunspot number, the time series of the logarithm of the X-ray flux, the solar wind speed, and the average strength of the interplanetary magnetic field as input parameters to our model. The results are validated with an out-of-sample testing set and benchmarked with other types of models.
{"title":"Forecasting Solar Energetic Proton Integral Fluxes with Bi-Directional Long Short-Term Memory Neural Networks","authors":"Mohamed Nedal, Kamen Kozarev, Nestor Arsenov, Peijin Zhang","doi":"10.1051/swsc/2023026","DOIUrl":"https://doi.org/10.1051/swsc/2023026","url":null,"abstract":"Solar energetic particles are mainly protons and originate from the Sun during solar flares or coronal shock waves. Forecasting the Solar Energetic Protons (SEP) flux is critical for several operational sectors, such as communication and navigation systems, space exploration missions, and aviation flights, as the hazardous radiation may endanger astronauts’, aviation crew, and passengers’ health, the delicate electronic components of satellites, space stations, and ground power stations. Therefore, the prediction of the SEP flux is of high importance to our lives and may help mitigate the negative impacts of one of the serious space weather transient phenomena on the near-Earth space environment. Numerous SEP prediction models are being developed with a variety of approaches, such as empirical models, probabilistic models, physics-based models, and AI-based models. In this work, we use the bidirectional long short-term memory (BiLSTM) neural network model architecture to train SEP forecasting models for three standard integral GOES channels (>10 MeV, >30 MeV, >60 MeV) with three forecast windows (1-day, 2-day, and 3-day ahead) based on daily data obtained from the OMNIWeb database from 1976 to 2019. As the SEP variability is modulated by the solar cycle, we select input parameters that capture the short-term, typically within a span of a few hours, and long-term, typically spanning several days, fluctuations in solar activity. We take the F10.7 index, the sunspot number, the time series of the logarithm of the X-ray flux, the solar wind speed, and the average strength of the interplanetary magnetic field as input parameters to our model. The results are validated with an out-of-sample testing set and benchmarked with other types of models.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135556933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeongheon Kim, Young-Sil Kwak, Changsup Lee, Jaewook Lee, Hosik Kam, Tae-Yong Yang, Geonhwa Jee, YongHa Kim
On November 1st and 2nd, 2021, four Halo coronal mass ejections were ejected from the Sun, releasing billions of tons of high-energy particles into interplanetary space. These were directed towards the Earth and reached our planet on November 3rd and 4th, 2021, generating the first G3-level extreme geomagnetic storm since the beginning of the 25th solar cycle. In this study, we investigate the thermospheric and ionospheric responses in the European sector to a G3-level storm using various observational data from Fabry-Perot interferometer, Ionospheric Connection Explorer/Michelson Interferometer for Global High-resolution Thermospheric Imaging (ICON/MIGHTI), and Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI). The results show positive ionospheric storms in the middle and low latitudes of Europe which may be associated with the equatorward and westward neutral winds induced by heating in the polar region. In contrast, negative storms were detected at high latitudes in association with the increase in thermospheric density (upwelling). These two antithetical responses were confirmed by using European ionosonde and total electron contents (TEC) observation chains distributed over a wide range of latitudes. Finally, we, for the first time, attempt to identify the imaginary boundary line between the two responses.
{"title":"Observational evidence of thermospheric wind and composition changes and the resulting ionospheric disturbances in the European sector during extreme geomagnetic storms","authors":"Jeongheon Kim, Young-Sil Kwak, Changsup Lee, Jaewook Lee, Hosik Kam, Tae-Yong Yang, Geonhwa Jee, YongHa Kim","doi":"10.1051/swsc/2023025","DOIUrl":"https://doi.org/10.1051/swsc/2023025","url":null,"abstract":"On November 1st and 2nd, 2021, four Halo coronal mass ejections were ejected from the Sun, releasing billions of tons of high-energy particles into interplanetary space. These were directed towards the Earth and reached our planet on November 3rd and 4th, 2021, generating the first G3-level extreme geomagnetic storm since the beginning of the 25th solar cycle. In this study, we investigate the thermospheric and ionospheric responses in the European sector to a G3-level storm using various observational data from Fabry-Perot interferometer, Ionospheric Connection Explorer/Michelson Interferometer for Global High-resolution Thermospheric Imaging (ICON/MIGHTI), and Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI). The results show positive ionospheric storms in the middle and low latitudes of Europe which may be associated with the equatorward and westward neutral winds induced by heating in the polar region. In contrast, negative storms were detected at high latitudes in association with the increase in thermospheric density (upwelling). These two antithetical responses were confirmed by using European ionosonde and total electron contents (TEC) observation chains distributed over a wide range of latitudes. Finally, we, for the first time, attempt to identify the imaginary boundary line between the two responses.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135402135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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