Level Of Geomagnetic Activity Research Articles

Systemic lupus Erythematosus and geomagnetic disturbances: a time series analysis

BackgroundTo examine the influence of solar cycle and geomagnetic effects on SLE disease activity.MethodsThe data used for the analysis consisted of 327 observations of 27-day Physician Global Assessment (PGA) averages from January 1996 to February 2020. The considered geomagnetic indices were the AP index (a daily average level for geomagnetic activity), sunspot number index R (measure of the area of solar surface covered by spots), the F10.7 index (measure of the noise level generated by the sun at a wavelength of 10.7 cm at the earth’s orbit), the AU index (upper auroral electrojet index), and high energy (> 60 Mev) proton flux events. Geomagnetic data were obtained from the Goddard Space Flight Center Space Physics Data Facility. A time series decomposition of the PGA averages was performed as the first step. The linear relationships between the PGA and the geomagnetic indices were examined using parametric statistical methods such as Pearson correlation and linear regression, while the nonlinear relationships were examined using nonparametric statistical methods such as Spearman’s rho and Kernel regression.ResultsAfter time series deconstruction of PGA averages, the seasonality explained a significant fraction of the variance of the time series (R2 = 38.7%) with one cycle completed every 16 years. The analysis of the short-term (27-day) relationships indicated that increases in geomagnetic activity Ap index (p < 0.1) and high energy proton fluxes (> 60 Mev) (p < 0.05) were associated with decreases in SLE disease activity, while increases in the sunspot number index R anticipated decreases in the SLE disease activity expressed as PGA (p < 0.05). The short-term correlations became statistically insignificant after adjusting for multiple comparisons using Bonferroni correction. The analysis of the long-term (297 day) relationships indicated stronger negative association between changes in the PGA and changes in the sunspot number index R (p < 0.01), AP index (p < 0.01), and the F10.7 index (p < 0.01). The long-term correlations remained statistically significant after adjusting for multiple comparisons using Bonferroni correction.ConclusionThe seasonality of the PGA averages (one cycle every 16 years) explains a significant fraction of the variance of the time series. Geomagnetic disturbances, including the level of geomagnetic activity, sunspot numbers, and high proton flux events may influence SLE disease activity. Studies of other geographic locales are needed to validate these findings.

Optimization of Radial Diffusion Coefficients for the Proton Radiation Belt During the CRRES Era

AbstractProton flux measurements from the Proton Telescope instrument aboard the CRRES satellite are revisited, and used to drive a radial diffusion model of the inner proton belt at 1.1 ≤ L ≤ 1.65. Our model utilizes a physics‐based evaluation of the cosmic ray albedo neutron decay (CRAND) source, and coulomb collisional loss is driven by a drift averaged density model combining results from the International Reference Ionosphere, NRLMSIS‐00 atmosphere and Radio Plasma Imager plasmasphere models, parameterized by solar activity and season. We drive our model using time‐averaged data at L = 1.65 to calculate steady state profiles of equatorial phase space density, and optimize our choice of radial diffusion coefficients based on four defining parameters to minimize the difference between model and data. This is first performed for a quiet period when the belt can be assumed to represent steady state. Additionally, we investigate fitting steady state solutions to time averages taken during active periods where the data exhibits limited deviation from steady state, demonstrated by CRRES measurements following the March 24, 1991 storm. We also discuss a way to make the optimization process more reliable by excluding periods of variability in plasmaspheric density from any time average. Lastly, we compare our resultant diffusion coefficients to those derived via a similar process in previous work, and diffusion coefficients derived for electrons from ground and in situ observations. We find that higher diffusion coefficients are derived compared with previous work, and suggest more work is required to derive proton diffusion coefficients for different geomagnetic activity levels.

Study of the evolution of the geomagnetic disturbances during the passage of high-speed streams from coronal holes in solar cycle 2009-2016

We study the geo-effectiveness of high-speed streams (HSS) detected during the consecutive eight years (2009 - 2016) period of solar cycle 24. These HSS are of different speeds and durations. During their passage, solar wind plasma and magnetic field parameters are also not similar. We utilize solar wind plasma and magnetic field parameters during the HSS passage in addition to two geomagnetic indices. Using the superposed-epoch analysis method, we study the time-evolution of geomagnetic disturbances concerning various solar wind parameters during the passage of HSS of different speeds and durations. We identify the solar wind parameter, which best follows the variations in geomagnetic parameters during the evolution of geomagnetic storms, from the start till recovery. Further, utilizing the level of geomagnetic activity due to individual HSS, we also search for solar wind parameter/function, which best correlates with the strength of geomagnetic storms due to these HSS.

Biotic and Abiotic Factors of Sperm nDNA Fragmentation in Farm Animals

Infertility and subfertility are among the global challenges of our time. Fertility in livestock farming is not only biologically important, it is also economically important. The aim of this study was to study the effect of these factors on sperm chromatin nucleus and to assess the impact of the fragmentation index degree on bull reproductive performance. The influence of abiotic factors such as ambient temperature, the level of geomagnetic activity and the biotic factor-infectious diseases of male reproductive organs - was studied. At high ambient temperatures (28-30°C), the proportion of sperm with damaged DNA increased by 70% compared to temperatures below 15°C. A Multivariate Analysis Of Variance (MANOVA) confirmed the influence of the geomagnetic activity factor on the degree of nuclear DNA fragmentation in bull sperm cells (level p<0.05). During the summer period, on days with increased geomagnetic activity, the Nuclear DNA fragmentation index in the samples studied was 20.5%. In some of the samples studied, this index exceeded 38% and the coefficient of variation for this index reached 44%. The proportion of sperm cells with abnormal movement also increased during geomagnetic activity. The content of such sperm cells reached 9.1% in bull semen ejaculates obtained during the winter period. More than 12% of sperm had non-progressive movement in summer semen obtained with a K-index ≥5.0, which was 83.8% higher than with a K-index ≤1.0. High geomagnetic activity and temperature and infection of the reproductive organs lead to pathological changes in spermatozoa, an increase in the proportion of spermatozoa with damaged nuclear DNA and a decrease in fertility.

Geomagnetic Activity Effects on CO2‐Driven Trend in the Thermosphere and Ionosphere: Ideal Model Experiments With GAIA

AbstractWe examine impacts of geomagnetic activity (GA) on CO2‐driven trend in the ionosphere and thermosphere using the Ground‐to‐topside Atmosphere Ionosphere model for Aeronomy whole atmosphere model. The model reveals three salient features. (1) Geomagnetic activities usually weakens the CO2‐driven trend at a fixed altitude. Among the IT parameters analyzed, the thermosphere mass density is the most robust indicator for CO2 cooling effect even with GA influences. (2) Geomagnetic activities can either strengthen or weaken the CO2‐driven trend in hmF2 and NmF2, depending on local time and latitudes. This renders the widely used linear fitting methods invalid for removing geomagnetic effects from observations. (3) An interdependency exists between the efficiency of CO2 forcing and geomagnetic forcing, with the former enhances at lower GA level, while the latter enhances at higher CO2 concentration. This could imply that the CO2‐driven trend would accelerate in periods of declining GA, while magnetic storms may have larger space weather impacts in the future with increasing CO2. These findings provide a preliminary model framework to understand interactions between the CO2 forcing from below and the geomagnetic forcing from above.

Geomagnetic disturbance effects on satellite attitude estimation

This study investigates the effects of magnetic disturbances resulting from geospace storms on the satellite attitudes estimated by EKF. It is shown that the increasing levels of geomagnetic activity affect geomagnetic field vectors predicted by IGRF and T89 models. Various sensor combinations including magnetometer, gyroscope, and sun sensor are evaluated for magnetically quiet and active conditions. Errors are calculated for estimated attitude angles and differences were discussed. This study emphasizes on the importance of environmental factors on the satellite attitude determination systems.

Schumann Resonance anomalies possibly associated with large earthquakes in Mexico

Using Schumann Resonance (SR) data of a station located in Mexico, we analyzed anomalies in frequency and amplitude of the first three SR harmonics within a window of 21 days, 15 days before and 5 days after, of 12 earthquakes of magnitude M > 5 that occurred in the Mexican Pacific coast. The period of study was from June 2013 to May 2018. In order to avoid SR anomalies likely produced by solar activity, we discarded periods with solar proton events; also, we distinguished three levels of geomagnetic activity (low, medium and high). We found either positive or negative statistically significant anomalies in frequency and amplitude around the day of the seismic event. However, a study of anomalies in periods of earthquakes of magnitude lower than M > 5 and quiet solar activity conditions also shows statistically significant anomalies. Therefore, these results concerning the presence of SR anomalies around the time of earthquakes in Mexico using the Mexican SR station data are not conclusive.

Pre-storm F2-layer Q-disturbances at middle latitudes: Do they exist?

Available manually scaled foF2 observations over 50 years on Juliusruh, 33 years on Slough, and 37 years on Rome stations were used to check the association between quiet-time foF2 disturbances (Q-disturbances) and following on isolated magnetic storms. Of course, such cases exist, however Pearson's contingency coefficient, Chi-square and Odds ratio tests applied to check a measure of association gave the absence of relationship even at the 95% confidence level. The lack of association makes it impossible to use F2-layer disturbances as precursors for magnetic storms. The observed cases of apparent relationship between two events should be considered as random and physically unconditioned. The published cases indicating the relationship between two events can be explained in the framework of regular F2-layer variations not related by any means to the following on magnetic storms. Plain language summaryThe Earth's upper atmosphere, including the ionosphere, is under total solar control – direct or indirect. F2-layer disturbances occurring during magnetically disturbed periods are due to these magnetic disturbances and they are not discussed in the paper. However there are quiet-time F2-layer disturbances (Q-disturbances) occurring under low and very low level of geomagnetic activity. The relationship of such Q-disturbances with following on isolated magnetic storms is analyzed in the paper. All available manually scaled hourly foF2 observations on Juliusruh (50 years), on Rome (37 years), and Slough (33 years) have been analyzed to estimate a measure of association between two binary variables: F2-layer Q-disturbances and isolated magnetic storms. Pearson's contingency coefficient, Chi-square and Odds ratio tests applied to check a measure of association gave the absence of relationship even at the 95% confidence level. This is an expected result as from physical point of view such relationship has no physical explanation. The lack of association makes it impossible to use foF2-layer disturbances as precursors for magnetic storms – the idea being discussed in the literature.The observed cases of apparent relationship between two events should be considered as random and physically unconditioned. The published cases indicating the relationship between two events can be explained in the framework of regular F2-layer variations not related by any means to the following on magnetic storms.

Statistical Study of Ion Upflow and Downflow Observed by PFISR

AbstractIon upflow in the F region and topside ionosphere can greatly influence the ion density and fluxes at higher altitudes and thus has significant impact on ion outflow. We investigated the statistical characteristics of ion upflow and downflow using a 3‐year (2011–2013) data set from the Poker Flat Incoherent Scatter Radar (PFISR). Ion upflow is twice more likely to occur on the nightside than on the dayside in PFISR observations, while downflow events occur more often in the afternoon sector. Upflow and downflow on the dayside tend to occur at altitudes ~500 km, higher than those on the nightside. Both upflow and downflow occur more frequently as ion convection speed increases. Upflow observed from 16 to 6 magnetic local time through midnight is associated with temperature and density enhancements. Occurrence rates of upflow on the nightside and downflow on the dayside increase with geomagnetic activity level. On the nightside, occurrence rate of ion upflow increases with enhanced solar wind and interplanetary magnetic field (IMF) drivers as well as southwestward local magnetic perturbations. The lack of correlation of upflow on the dayside with the solar wind and IMF parameters is because PFISR is usually equatorward of the dayside auroral zone. Occurrence rate of downflow does not show strong dependence on the solar wind and IMF conditions. However, it occurs much more frequently on the dayside when the IMF By &gt; 10 nT and the IMF Bz &lt; −10 nT, which we suggest is associated with the decaying of the dayside storm‐enhanced density (SED) and the SED plume.

Dynamical complexity in Swarm electron density time series using Block entropy

Our goal in this study is to investigate the dynamical complexity of the electron density profiles in the topside ionosphere as measured by the Swarm mission, employing the use of symbolic information-theoretic techniques. We perform a Block entropy analysis for a time interval associated with the most intense magnetic storm of solar cycle 24, which occurred on 17 March 2015. We produce entropy maps for varying degrees of magnetospheric disturbance, resolving the different effects that the various geomagnetic activity levels have in the dynamics of the complex magnetosphere-ionosphere coupling system. Understanding the impact of these effects on the ionospheric plasma constitutes a crucial factor for the functionality of the modern technological infrastructure operating around the Earth and, thus, human welfare.

The Day‐Night Difference and Geomagnetic Activity Variation of Energetic Electron Fluxes in Region of South Atlantic Anomaly

AbstractUtilizing the DEMETER observations at 670 km, we examined the day‐night difference of energetic electrons (100–800 keV) in the South Atlantic Anomaly (SAA) region and their dependence on geomagnetic activities in different seasons. Under geomagnetically quiet conditions, the fluxes of higher‐energy electrons (&gt;200 keV) in the dusk and midnight (MLT ~ 19–24 hr) are usually larger than those in the morning (MLT ~ 8–12 hr) in the core region of the SAA (−50 ≤ λ ≤ − 20deg) during the northern and southern summers (21 March 2007 to 23 September 2007 and 23 September 2007 to 21 March 2008). The day‐night difference of energetic electrons in SAA region depends not only on the electron energy but also on the geomagnetic activity levels. Enhanced geomagnetic activities increase the energetic electrons in morning and hence weaken their day‐night difference in the SAA region.

Climatology Characteristics of Ionospheric Irregularities Described with GNSS ROTI

At equatorial and high latitudes, the intense ionospheric irregularities and plasma density gradients can seriously affect the performances of radio communication and satellite-based navigation systems; that represents a challenging topic for the scientific and engineering communities and operational use of communication and navigation services. The GNSS-based ROTI (rate of TEC index) is one of the most widely used indices to monitor the occurrence and intensity of ionospheric irregularities. In this paper, we examined the long-term performance of the ROTI in terms of finding the climatological characteristics of TEC fluctuations. We considered the different scale temporal signatures and checked the general sensitivity to the solar and geomagnetic activity. We retrieved and analyzed long-term time-series of ROTI values for two chains of GNSS stations located in European and North-American regions. This analysis covers three full years of the 24th solar cycle, which represent different levels of solar activity and include periods of intense geomagnetic storms. The ionospheric irregularities’ geographical distribution, as derived from ROTI, shows a reasonable consistency to be found within the poleward/equatorward boundaries of the auroral oval specified by empirical models. During magnetic midnight and quiet-time conditions, the equatorward boundary of the ROTI-derived ionospheric irregularity zone was observed at 65–70° of north magnetic latitude, while for local noon conditions this boundary was more poleward at 75–85 magnetic latitude. The ionospheric irregularities of low-to-moderate intensity were found to occur within the auroral oval at all levels of geomagnetic activity and seasons. At moderate and high levels of solar activity, the intensities of ionospheric irregularities are larger during local winter conditions than for the local summer and polar day conditions. We found that ROTI displays a selective latitudinal sensitivity to the auroral electrojet activity—the strongest dependence (correlation R &gt; 0.6–0.8) was observed within a narrow latitudinal range of 55–70°N magnetic latitude, which corresponded to a band of the largest ROTI values within the auroral oval zone expanded equatorward during geomagnetic disturbances.

Dawnside Auroral Polarization Streams

AbstractAlthough the postmidnight‐to‐dawn sector of the auroral ionosphere contains interesting dynamic phenomena that may significantly impact the magnetosphere‐ionosphere‐thermosphere system, it has been much less studied than the dusk‐to‐premidnight sector. We discuss a dynamic phenomenon in the postmidnight‐to‐dawn sector of the auroral oval, eastward fast flows mainly within the expanse of the Region 1 current (its part equatorward of the polar cap). These flows peak and have a steep speed gradient (increase from low to high latitude) near the interface between the Region 1 and Region 2 currents. Because such flows correspond to an electric field that most likely comes from enhanced Region 2 currents and an associated spatial conductivity gradient, their generation mechanism is analogous to that of a subauroral polarization stream. Therefore, we refer to such an eastward flow as a dawnside auroral polarization stream (DAPS). We show several examples of the presence and absence of DAPS under different geomagnetic activity levels. A DAPS' electric field can heat the ionosphere (and thus the thermosphere), change the convection pattern of the magnetosphere‐ionosphere system, and modify the drift path of magnetospheric particles. Because a DAPS' flow peak maps to a major site of magnetic‐kinetic energy conversion in the magnetosphere (the transition region between dipole and stretched field), it may be important for the conversion. A DAPS' steep flow gradient is also potentially important; it may lead to instabilities, such as that responsible for auroral Omega bands. Given its potential importance, knowledge of DAPS is fundamental for understanding the magnetosphere‐ionosphere‐thermosphere system.

Asymmetric behaviour and geomagnetic dependencies of zonal winds in the middle latitude upper thermosphere

In this study we use the CHAMP wind observations from 2002 to 2004 to investigate features of mid-latitude thermospheric winds at low and high geomagnetic activity levels. The winds are observed between the geomagnetic latitudes 40–50° north or south within an altitude range of 370–450 Km and averaged longitudinally. The low geomagnetic activity level wind generally leads eastward in both hemispheres for all the seasons. Maximum westward speeds going above 100 m/s are observed at all levels of geomagnetic activity. Most investigations on F-region parameters assume the equinoxes are fundamentally the same. A first time separation of Equinox season using CHAMP winds reveals equinoctial asymmetric behavior of the wind speed at the two levels considered. Interhemispheric asymmetry in neutral wind behaviour is clearly evident in the solstice seasons with local winds considered in each of the hemispheres. This is consistent with asymmetry in the amount of solar illumination received in each of the hemispheres and differences in the magnetic field strength at magnetically conjugate regions.

Geomagnetic Storm‐Induced Plasma Density Enhancements in the Southern Polar Ionospheric Region: A Comparative Study Using St. Patrick's Day Storms of 2013 and 2015

AbstractThe occurrence of St. Patrick's Day (17 March) geomagnetic storms during two different years (2013 and 2015) with similar solar flux levels but varying storm intensity provided an opportunity to compare and contrast the responses of the ionosphere‐thermosphere (IT) system to different levels of geomagnetic activity. The evolution of positive ionospheric storms at the southern polar stations Bharati (76.6°S MLAT) and Davis (76.2°S MLAT) and its causative connection to the solar wind driving mechanisms during these storms has been investigated in this paper. During the main phase of both the storms, significant enhancements in TEC and phase scintillation were observed in the magnetic noon/ midnight period at Bharati and Davis. The TEC in the midnight sector on 17 March 2015 was significantly higher compared to that on 17 March 2013, in line with the storm intensity. The TEC enhancements during both the storm events are associated with the formation of the storm‐enhanced densities (SEDs)/tongue of ionization (TOI). The strong and sustained magnetopause erosion led to the prevalence of stronger storm time electric fields (prompt penetration electric field (PPEF)/subauroral polarization streams (SAPS)) for long duration on 17 March 2015. This combined with the action of neutral winds at midlatitudes favored the formation of higher plasma densities in the regions of SED formation on this day. The same was weaker during the 17 March 2013 storm due to the fast fluctuating nature of interplanetary magnetic field (IMF) Bz. This study shows that the duration and extent of magnetopause erosion play an important role in the spatiotemporal evolution of the plasma density distribution in the high‐midlatitude ionosphere.

Neural network classification of substorm geomagnetic activity caused by solar wind magnetic clouds

A Kohonen artificial neural network (ANN) was used to classify patterns of causal relationships between the level of geomagnetic activity in the auroral zone and plasma and magnetic field parameters in the body of an interplanetary magnetic cloud (IMO). Terrestrial and satellite observations during 33rd interplanetary magnetic clouds recorded from 1998 to 2012 are examined in detail. Experiments with the ANN during its fast training show that substorm discrimination by their intensity by three classes plus a “collector” for collecting atypical events is optimal for the study. An analysis of the classification result studies showed that each selected class of substorms corresponds to a specific set of perturbations of the plasma parameters and the magnetic field of the IMO. Using the integral characteristics of the plasma and the IMF components as input parameters of the ANN allowed us to detect the levels of the expected intensity of the AL index with an accuracy of up to 70%. The created ANNs can be used to restore the AL index both during periods of isolated magnetospheric substorms and during periods of a series of continuous successive substorms, one after another.

Transmission Lines in Poland and Space Weather Effects

We analyze the solar influence of space weather events on Polish energy infrastructure via geomagnetic disturbances. We consider two time intervals of very different levels of solar activity (SA) in the course of the solar activity cycle 24: 2010—an early rising phase of SA, near the solar minimum and 2014—solar maximum. From the total number of electrical grid failures, we extract almost five thousand failures in 2010 and more than ten thousand in 2014, which could be related to space weather effects. We analyze data of failures having unidentified causes, failures coupled with the aging of transmission network elements and electronic devices, which appeared during the time intervals of enhanced geomagnetic activity. We show that around the times of increasing geomagnetic activity level, the amount of transmission lines failures in the groups mentioned above grows, but mostly with some delay. It might be connected to some cumulative effect due to the result of transient states and their propagation in the distribution network. Although we do not exclude that the other factors may play a role, the solar-originating disturbances strengthen these effects.

Estimating the fate of oxygen ion outflow from the high-altitude cusp

Abstract. We have investigated the oxygen escape-to-capture ratio from the high-altitude cusp regions for various geomagnetic activity levels by combining EDI and CODIF measurements from the Cluster spacecraft. Using a magnetic field model, we traced the observed oxygen ions to one of three regions: plasma sheet, solar wind beyond a distant X-line or dayside magnetosheath. Our results indicate that 69 % of high-altitude oxygen escapes the magnetosphere, from which most escapes beyond the distant X-line (50 % of total oxygen flux). Convection of oxygen to the plasma sheet shows a strong dependence on geomagnetic activity. We used the Dst index as a proxy for geomagnetic storms and separated data into quiet conditions (Dst&gt;0 nT), moderate conditions (0&gt;Dst&gt;-20 nT), and active conditions (Dst&lt;-20 nT). For quiet magnetospheric conditions we found increased escape due to low convection. For active magnetospheric conditions we found an increase in both parallel velocities and convection velocities, but the increase in convection velocities is higher, and thus most of the oxygen gets convected into the plasma sheet (73 %). The convected oxygen ions reach the plasma sheet in the distant tail, mostly beyond 50 RE.

Statistical Analysis of Equatorial Plasma Irregularities Retrieved From Swarm 2013–2019 Observations

AbstractIn this study, we present a statistical analysis of equatorial plasma irregularities (EPIs) by using in situ plasma density measurements of the Swarm constellation from December 2013 to December 2019. The occurrence patterns for both postsunset and postmidnight EPIs with respect to longitude, season, local time, latitude, solar activity, and geomagnetic activity level are investigated. The main findings are as follows: (1) The postsunset/postmidnight EPIs occurrence rates exhibit different longitudinal and seasonal dependence: The postsunset EPIs have the maximum occurrence rate over the American‐Atlantic sectors during the December solstice and equinoxes, and the postmidnight EPIs have the maximum occurrence rate during the June solstice, especially over the African sector. (2) The postsunset EPIs occurrence rates have a positive correlation with solar activity, while the postmidnight EPIs are negatively correlated with it. (3) The latitudinal distribution of EPIs exhibits a double‐peak structure around ±5° magnetic latitude with a more significant peak in the summer hemisphere. (4) The EPIs occurrence rate increases with increasing geomagnetic activity level. (5) The main controlling factors for the distribution of postsunset EPIs are the magnetic declination angle, equatorial vertical E × B drift, and thermospheric zonal wind. For the postmidnight EPIs, the main controlling factors are likely to be atmospheric gravity waves and equatorward thermospheric meridional wind associated with midnight temperature maximum.

Auroral Structure and Dynamics From GOLD

AbstractThe Global‐scale Observations of the Limb and Disk (GOLD) mission data contain significant quantitative information about the aurora on a global scale. Here we present techniques for quantifying such information, including the temporal development of the structure within the auroral oval using the GOLD images. These techniques are applied to auroral observations in the GOLD data, in particular showing an example of how the longitudinal structure within the aurora varies over the course of six consecutive days with differing levels of geomagnetic activity. A simple model of the solar‐induced airglow is presented that is used to remove the sunlight contamination from the dayside auroral observations. Comparisons to ground‐based auroral imaging are used for the overall auroral context and to make estimates of the proportionality between the intensities of the green line (557.7 nm) emission in the visible and the 135.6 nm emissions in the GOLD data. These observations are consistent with the intensity of the 135.6 nm auroral emission being on the same order as the intensity of the 557.7 nm auroral emission. They were both found to be around 1 kR for a stable auroral arc on a day with low geomagnetic activity (3 November 2018) and around 10 kR for an active auroral display on a day with higher levels of geomagnetic activity (5 November 2018). This could have important implications for making direct comparisons between space‐based ultraviolet auroral imaging and ground‐based visible‐light auroral imaging and the total energy input estimates that are derived from them.