Journal of Space Weather and Space Climate最新文献

{"title":"Multi-Instrument Observations and Tracking of a Coronal Mass Ejection Front From Low to Middle Corona","authors":"O. Stepanyuk, K. Kozarev","doi":"10.1051/swsc/2023033","DOIUrl":"https://doi.org/10.1051/swsc/2023033","url":null,"abstract":"The shape and dynamics of coronal mass ejections (CMEs) varies significantly based on the instrument and wavelength used. This has led to significant debate about the proper definitions of CME/shock fronts, pile-up/compression regions, and cores observed in projection in optically thin vs. optically thin emission. Here we present an observational analysis of the evolving shape and kinematics of a large-scale CME that occurred on May 7, 2021 on the eastern limb of the Sun as seen from 1 au. The eruption was observed continuously, consecutively by the Atmospheric Imaging Assembly (AIA) telescope suite on the Solar Dynamics Observatory (SDO), the ground-based COronal Solar Magnetism Observatory (COSMO) K-coronagraph (K-Cor) on Mauna Loa, and the C2 and C3 telescopes of the Large Angle Solar Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SoHO). We apply the recently developed Wavetrack Python suite for automated detection and tracking of coronal eruptive features to evaluate and compare the evolving shape of the CME front as it propagated from the solar surface out to 20 solar radii. Our tool allows tracking features beyond just the leading edge and is an important step towards semi-automatic manufacturing of training sets for training data-driven image segmentation models for solar imaging. Our findings confirm the expected strong connection between EUV waves and CMEs. Our novel, detailed analysis sheds observational light on the details of EUV wave-shock-CME relations that is lacking for the gap region between the low and middle corona.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139450584","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}

{"title":"A Bayesian approach to the drag-based modelling of ICMEs","authors":"S. Chierichini, Gregoire Francisco, R. Mugatwala, R. Foldes, E. Camporeale, Giancarlo De Gasperis, L. Giovannelli, G. Napoletano, Dario Del Moro, Robertus Erdelyi","doi":"10.1051/swsc/2023032","DOIUrl":"https://doi.org/10.1051/swsc/2023032","url":null,"abstract":"Coronal Mass Ejections (CMEs) are huge clouds of magnetised plasma expelled from the solar corona that can travel towards the Earth and cause significant space weather effects.\u0000   The Drag-Based Model (DBM) describes the propagation of CMEs in an ambient solar wind as analogous to an aerodynamic drag. The drag-based approximation is popular because it is a simple analytical model that depends only on two parameters, the drag parameter $gamma$ and the solar wind speed $w$. DBM thus allows us to obtain reliable estimates of CME transit time at low computational cost.\u0000    Previous works proposed a probabilistic version of DBM, the Probabilistic Drag Based Model (P-DBM), which enables the evaluation of the uncertainties associated with the predictions.\u0000    In this work, we infer the \"a-posteriori\" probability distribution functions (PDFs) of the $gamma$ and $w$ parameters of the DBM by exploiting a well-established Bayesian inference technique: the Monte Carlo Markov Chains (MCMC) method.\u0000   By utilizing this Bayesian method through two different approaches, an ensemble and an individual approach, we obtain specific DBM parameter PDFs for two ensembles of CMEs: those travelling with fast and slow solar wind, respectively. \u0000 \u0000   Subsequently, we assess the operational applicability of the model by forecasting the arrival time of CMEs. \u0000    While the ensemble approach displays notable limitations, the individual approach yields promising results, demonstrating competitive performances compared to the current state-of-the-art, with a mean absolute error (MAE) of 9.86 ± 4.07 hours achieved in the best-case scenario.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139005518","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}

{"title":"Reconstruction of electron precipitation spectra at the top of the upper atmosphere using 427.8 nm auroral images","authors":"Elisa Robert, Mathieu Barthelemy, Gael Cessateur, Angélique Woelfflé, Hervé Lamy, Simon Bouriat, Magnar Gullikstad Johnsen, Urban Brändström, Lionel Biree","doi":"10.1051/swsc/2023028","DOIUrl":"https://doi.org/10.1051/swsc/2023028","url":null,"abstract":"We present an innovative method to reconstruct the characteristics of precipitated electrons in auroral regions from optical measurements. This method is based on an optimization implemented between numerical simulations of the Transsolo code and tomographic maps made from the Auroral Large Imaging System (ALIS) network. We focus on the Volume Emission Rate (VER) of the blue line N_{2}^{+} 1NG 427.8 nm, which is the most representative line of the energy deposition by electrons. The optimization is tested with the ALIS measurements carried out on March 05, 2008, at 18:41:30 UT and 18:42:40 UT. The reconstruction is performed by extracting the energy flux and the mean energy of the precipitating particles. Both Maxwellian and quasi-monoenergetic energy distributions are considered. Calculations performed with a Maxwellian energy distribution yielded an mean energy ranging from 1.8 to 5.2 keV with energy flux from 0.1 to 44.3 erg.cm^{-2}.s^{-1} for 18:41:30 UT, and an mean energy from 2.2 to 9.5 keV with energy flux from 2.1 to 136.7 erg.cm^{-2}.s^{-1} for 18:42:40 UT. Assuming a quasi-monoenergetic energy distribution, we find an mean energy of 4.2 to 11.82 keV with energy flux ranging from 0.1 to 45 erg.cm^{-2}.s^{-1} for 18:41:30 UT, and 8 to 17.1 keV with energy flux ranging from 2.2 to 110.1 erg.cm^{-2}.s^{-1} for 18:42:40 UT. Moreover, we show this method allows to reconstruct the energy characteristic of the precipitating electrons on a large region covering approximately 150 km by 150 km. This study also shows that some VER profiles of the maps are better fitted by a quasi mono-energetic distributions while some others correspond to broadband distributions. It appears clearly that the energy flux is linked to the column integrated intensity, the mean energy is linked with the peak altitude of the emission and the width of the energy distribution with the altitude thickness of the emissions.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136227406","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}

{"title":"Karl von Lindener's Sunspot Observations during 1800 – 1827: Another Long-Term Dataset for the Dalton Minimum","authors":"Hisashi Hayakawa, Rainer Arlt, Tomoya Iju, Bruno Besser","doi":"10.1051/swsc/2023023","DOIUrl":"https://doi.org/10.1051/swsc/2023023","url":null,"abstract":"On a centennial timescale, solar activity oscillates quasi-periodically and also tends to get into a low-activity period. The Dalton Minimum (c.a. 1790s–1820s) was one of such low-activity periods that had been captured in telescopic sunspot observations. However, it has been challenging to analyse the Dalton Minimum, as contemporary source records remained mostly unpublished and almost inaccessible for the scientific community. Recent studies have established reliable datasets for sunspot group number, sunspot number, and sunspot positions. This study further analyzes independent Silesian sunspot observations from 1800 to 1827 archived in a manuscript the Library WrocławUniversity (Ms AKC.1985/15), complements it with the metadata for the observer Karl Christian Reinhold von Lindener. We identified 547 days of sunspot observations in these records and derived the sunspot group number, individual sunspot number, and sunspot positions between 1800 and 1827. The results of this study have significantly revised the von Lindener’s sunspot group number, which was only known for 517 days in scientific databases, and remove contamination from general descriptions. Using our results, we extend investigations into individual sunspots and derived their positions. In our analysis, we locate von Lindener’s sunspot positions in both solar hemispheres and contrast the Dalton Minimum with the Maunder Minimum, adding further independent credits to the previous results for Derfflinger and Prantner’s datasets. Sunspot positions are also slightly biased towards the northern solar hemisphere in early Solar Cycle 6 (1812 – 1813). The high-latitude sunspot positions indicate the onset of Solar Cycle 7 as early as June 1822.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585479","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}

{"title":"On the detection of a solar radio burst event occurred on 28 August 2022 and its effect on GNSS signals as observed by ionospheric scintillation monitors distributed over the American sector","authors":"I. G. Wright, Fabiano Rodrigues, J. Gomez Socola, A. O. Moraes, J. F. G. Monico, J. Sojka, L. Scherliess, D. Layne, I. Paulino, R. A. Buriti, C. G. M. Brum, P. Terra, K. Deshpande, P. R. Vaggu, P. J. Erickson, N. A. Frissell, J. Makela, D. Scipion","doi":"10.1051/swsc/2023027","DOIUrl":"https://doi.org/10.1051/swsc/2023027","url":null,"abstract":"As part of an effort to observe and study ionospheric disturbances and their effects on radio signals used by Global Navigation Satellite Systems (GNSS), alternative low-cost GNSS-based ionospheric scintillation and total electron content (TEC) monitors have been deployed over the American sector. During inspection of the observations made on 28 August 2022, we found increases in the amplitude scintillation index (S4) reported by the monitors for the period between approximately 17:45 UT and 18:20 UT. The distributed, dual-frequency observations made by the sensors allowed us to determine that the increases in S4 were not caused by ionospheric irregularities. Instead, they resulted from C/No variations caused by a solar radio burst (SRB) event that followed the occurrence of two M-class X-ray solar flares and a Halo coronal mass ejection. The measurements also allowed us to quantify the impact of the SRB on GNSS signals. The observations show that the SRB caused maximum C/No fadings of about 8 dB-Hz (12 dB-Hz) on L1 ~ 1.6 GHz (L2 ~ 1.2 GHz) for signals observed by the monitor in Dallas for which the solar zenith angle was maximum (~24.4o) during the SRB. Calculations using observations made by the distributed monitors also show excellent agreement for estimates of the maximum (vertical equivalent) C/No fadings in both L1 and L2. The calculations show maximum fadings of 9 dB-Hz for L1 and of 13 dB-Hz for L2. Finally, the results exemplify the usefulness of the low-cost monitors for studies beyond those associated with ionospheric irregularities and scintillation.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135217802","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}

{"title":"Prediction of even and odd sunspot cycles","authors":"Timo Asikainen, Jani Mantere","doi":"10.1051/swsc/2023024","DOIUrl":"https://doi.org/10.1051/swsc/2023024","url":null,"abstract":"Here we study the prediction of even and odd numbered sunspot cycles separately, thereby taking into account the Hale cyclicity of solar magnetism. We first show that the temporal evolution and shape of all sunspot cycles are extremely well described by a simple parameterized mathematical expression. We find that the parameters describing even sunspot cycles can be predicted quite accurately using the sunspot number 41 months prior to sunspot minimum as a precursor. We find that the parameters of the odd cycles can be best predicted with maximum geomagnetic aa index close to fall equinox within a 3-year window preceding the sunspot minimum. We use the found precursors to predict all previous sunspot cycles and evaluate the performance with a cross-validation methodology, which indicates that each past cycle is very accurately predicted. For the coming sunspot cycle 25 we predict an amplitude of 171 ± 23 and the end of the cycle in September 2029 ±1.9 years. We are also able to make a rough prediction for cycle 26 based on the predicted cycle 25. While the uncertainty for the cycle amplitude is large we estimate that the cycle 26 will most likely be stronger than cycle 25. These results suggest an increasing trend in solar activity for the next decades.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47183184","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}

{"title":"Statistical Validation of Ionospheric Electron Density Profiles Retrievals from GOES Geosynchronous Satellites","authors":"I. Zakharenkova, I. Cherniak, Scott Gleason, Douglas Hunt, D. Freesland, A. Krimchansky, J. McCorkel, G. Ramsey, Jim Chapel","doi":"10.1051/swsc/2023022","DOIUrl":"https://doi.org/10.1051/swsc/2023022","url":null,"abstract":"In this paper, we discuss a novel retrieval of ionospheric electron density profiles using the Radio Occultation (RO) technique applied to measurements captured by the GPS receivers on-board two Geostationary Operational Environmental Satellites (GOES). The GOES satellites operate at ~35800 km altitude and are primarily weather satellites that operationally contribute continuous remote-sensing data for real-time weather forecasting, as well as near Earth environment monitoring and Sun observations. The GPS receivers onboard GOES-16 and GOES-17 satellites can track GPS signals propagated through the Earth’s atmosphere, and although the receivers are primarily designed for navigation and station-keeping maneuvers, these GPS measurements that traverse the Earth’s atmosphere can be used to retrieve the ionospheric electron density profiles. This process poses a range of technical challenges. GOES RO links are different from the traditional low Earth orbit (LEO) RO geometry since the receiver is located in an orbit that is higher in altitude than the GPS constellation of transmitters. Additionally, the GPS receivers onboard GOES satellites provide only single frequency GPS L1 observations and have clocks much less stable than those typically used for RO measurements. The geographical distribution of the retrieved GEO-based RO profiles was found to be uniquely constrained and repeatable based on the relative geo-stationary fixed positions in the Earth Centered Earth Fixed reference frame with respect to the GPS constellation orbiting at lower altitude, and significantly different from the coverage patterns of LEO-based RO missions. We demonstrate the successful application of the proposed RO profiling technique with a statistically significant set of GPS observations from GOES-16 and GOES-17 satellites over several years of data collection. This enabled us to retrieve more than 10K ionospheric electron density profiles with a maximum altitude up to 1000–2000 km, much higher than any existing LEO-based RO mission. We demonstrate good performance of GEO-based RO measurements for properly specifying the vertical distribution of ionospheric plasma density by comparing the profiles dataset from the GOES RO experiment with independent reference observations—ground-based ionosondes and LEO-based RO missions, as well as model simulation results provided by the empirical International Reference Ionosphere model. Over multiple years of observations, statistical analysis of discrepancies between the ionospheric F2 layer peak parameters (peak density and height) derived from geosynchronous GOES observations and reference measurements was conducted. This analysis reveals a very good agreement between GOES RO electron density profiles and independent types of measurements in both the F2 peak and in the profile shape.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47338399","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}

{"title":"Towards the possibility to combine LOFAR and GNSS measurements to sense ionospheric irregularities","authors":"P. Flisek, B. Forte, R. Fallows, K. Kotulak, A. Krankowski, M. Bisi, M. Mevius, A. Froń, C. Tiburzi, M. Soida, Bartosz Śmierciak, M. Grzesiak, B. Matyjasiak, M. Pożoga, B. Dabrowski, G. Mann, C. Vocks, P. Zucca, L. Blaszkiewicz","doi":"10.1051/swsc/2023021","DOIUrl":"https://doi.org/10.1051/swsc/2023021","url":null,"abstract":"Inhomogeneities within the ionospheric plasma density affect trans-ionospheric radio signals, causing radio wave scintillation in the amplitude and phase of the signals. The amount of scintillation induced by ionospheric irregularities typically decreases with the radio wave frequency. As the ionosphere affects a variety of technological systems (e.g., civil aviation, financial operations) as well as low-frequency radio astronomy observations, it is important to detect and monitor iono-\u0000spheric effects with higher accuracy than currently available. Here, a novel methodology for the detection and characterization of ionospheric irregularities is established on the basis of LOFAR scintillation measurements at VHF that takes into account of the lack of ergodicity in the intensity fluctuations induced by scintillation. The methodology estimates the S 4 scintillation index originating from irregularities with spatial scales in the inertial sub-range of electron density fluctuations in the ionosphere. The methodology is illustrated by means of observations that were collected through the Polish LOFAR stations located in Bałdy, Borówiec and Łazy: its validation was carried out by comparing LOFAR VHF scintillation observations with independent GNSS observations that were collected through a high-rate receiver located near the LOFAR station in Bałdy as well as through geodetic receivers from the Polish ASG-EUPOS network. Two case stud-\u0000ies are presented: 31 March 2017 and 28 September 2017. The comparison between LOFAR S4 observations and independent ionospheric measurements of both scintillation and rate of change of TEC from GNSS reveals that the sensitivity of LOFAR and GNSS to ionospheric structures is different as a consequence of the frequency dependency of radio wave scintillation. Furthermore, it can be noticed that observations of LOFAR VHF scintillation can be utilised to detect plasma\u0000structures forming in the mid-latitude ionosphere, including electron density gradients occurring over spatial scales that are not necessarily detected through traditional GNSS measurements: the detection of all spatial scales is important for a correct monitoring and modelling of ionospheric processes. Hence, the different sensitivity of LOFAR to ionospheric structures, in addition to traditional GNSS ionospheric measurements, allows to expand the knowledge of ionospheric processes.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45508460","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}

{"title":"Assessment of the radiation risk at flight altitudes for an extreme solar particle storm of 774 AD","authors":"A. Mishev, S. Panovska, I. Usoskin","doi":"10.1051/swsc/2023020","DOIUrl":"https://doi.org/10.1051/swsc/2023020","url":null,"abstract":"Intense solar activity can lead to an acceleration of solar energetic particles and accordingly in crease in the complex radiation field at commercial aviation flight altitudes. We considered here the strongest ever observed event, namely that of 774 AD registered on the basis of cosmogenic isotope measurements, and computed the ambient dose at aviation altitude(s). Since the spectrum of solar protons during 774 AD event can not be directly obtained, as a first step, we derived the spectra of the solar protons during the GLE #5, the strongest event observed by direct measurements, which was subsequently scaled to the size of the 774 AD event and eventually used as input to the corresponding radiation model. The GLE #5 was considered as a conservative approach because it revealed the hardest-ever derived energy spectrum. The global map of the ambient dose was computed under realistic data-based reconstruction of the geomagnetic field during the 774 AD epoch, based on paleomagnetic measurements. A realistic approach on the basis of a GLE #45 was also considered, that is by scaling an event with softer spectra and lower particle fluxes compared to the GLE#5. The altitude dependence of the event integrated dose at altitudes from 30 kft to 50 kft was also computed for the both scenarios. The presented here study of the radiation\u0000effects during the extreme event of 774 AD give the necessary basis to be used as a reference to assess the worst-case scenario for a specific threat, that is radiation dose at flight altitudes.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46462908","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}

{"title":"The Effects of Estimating a Photoionization Parameter within a Physics-Based Model using Data Assimilation","authors":"D. Hodyss, D. Allen, D. Tyndall, P. Caffrey, S. McDonald","doi":"10.1051/swsc/2023019","DOIUrl":"https://doi.org/10.1051/swsc/2023019","url":null,"abstract":"Data assimilation (DA) is the process of merging information from prediction models with noisy observations to produce an estimate of the state of a physical system.  In ionospheric physics-based models, the solar ionizing irradiance is commonly estimated from a solar index like F10.7.  The goal of this work is to provide the fundamental understanding necessary to appreciate how a DA algorithm responds to estimating an external parameter driving the model’s interpretation of this solar ionizing irradiance.  Therefore, in this work we allow the DA system to find the F10.7 value that delivers the degree of photoionization that leads to a predicted electron density field that best matches the observations.  To this end, we develop a heuristic model of the ionosphere along the magnetic equator that contains physics from solar forcing and recombination/plasma diffusion, which allows us to explore the impacts of strongly forced system dynamics on DA.  This framework was carefully crafted to be both linear and Gaussian, which allows us to use a Kalman filter to clearly see how: 1) while recombination acts as a sink on the information in the initial condition for ionospheric field variables, recombination does not impact the information in parameter estimates in the same way, 2) when solar forcing dominates the electron density field, the prior covariance matrix becomes dominated by its leading eigenvector whose structure is directly related to that of the solar forcing, 3) estimation of parameters for forcing terms leads to a time-lag in the state estimate relative to the truth, 4) the performance of a DA system in this regime is determined by the relative dominance of solar forcing and recombination to that of the smaller-scale processes and 5) the most impactful observations on the electron density field and on the solar forcing parameter are those observations on the sunlit side of the ionosphere.  These findings are then illustrated in a full physics-based ionospheric model using an ensemble Kalman filter DA scheme.","PeriodicalId":17034,"journal":{"name":"Journal of Space Weather and Space Climate","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41409919","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}