Radio Occultation Electron Density Profiles Research Articles

Nighttime wavenumber-four and plasma depletion bays observed by FORMOSAT-5/AIP, ICON/IVM, and COSMIC-2/RO data

We examine nighttime longitudinal structures of ion density and ion velocity in wavenumber-four (WN4) and plasma depletion bays (PDBs) observed by FORMOSAT-5 (F5) and ICON, as well as electron density by FORMOSAT-7/COSMIC-2 (F7C2) in 2020. Three PDBs significantly occur in June and December solstices, while WN4 prominently appear in March and September equinox. F5/AIP (advanced ionospheric probe) ion velocities tend to be westward (eastward) at the PDB (WN4) longitudes, which shows that the ion density maximum and minimum are coincident with the eastward ion velocity maximum and minimum, respectively. ICON/IVM (ion drift meter) field-aligned velocities further reveal that the summer to winter trans-equatorial flow is essential to form PDBs, which further results in upward and downward ion drifts in the upstream and downstream areas (summer and winter hemisphere), respectively. Furthermore, F7C2 radio occultation electron density profiles reveal that three PDBs could prominently appear in June and December solstice in the upper ionosphere. F5/AIP and ICON/IVM ion velocities show that the zonal plasma drift is essential to form nighttime WN4 and PDBs, and the summer to winter trans-equatorial flow is important to PDBs.

Statistical validation of ionospheric electron density profiles retrievals from GOES geosynchronous satellites

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 Global Positioning System (GPS) receivers onboard two Geostationary Operational Environmental Satellites (GOES). The GOES satellites operate at ~35,800 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 geostationary 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 10,000 ionospheric electron density profiles with a maximum altitude of 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 the profile shape.

Evaluation for effects of variable Martian upper atmosphere on ionospheric peak electron density based on the MGS RO observation

The Martian ionospheric peak is dominated by photochemical processes at dayside. Its primary variations can be well described by the Chapman theory; nevertheless, deviation still exists between observation and the theory. Some factors may be responsible for that deviation, in which the variable upper atmosphere is an important one. Ionospheric radio occultation (RO) measurement can be used to investigate the effect of the upper atmosphere on the Martian ionosphere, since concurrent variations of the ionospheric peak and the neutral scale height (Hn) can be estimated from RO electron density profiles. In this study, Hn was estimated from the Mars Global Surveyor (MGS) RO observation to quantitatively evaluate the effect of the upper atmosphere on the variability of the peak electron density of the M2 layer (NmM2). That effect manifests in the abilities of solar zenith angle functions for describing NmM2 variability and in the NmM2 deviation from the Chapman theory. Compared with the Chapman function, the simple cosine function is sufficiently accurate for describing dayside NmM2 variation owing to the cold Martian upper atmosphere that consists of heavier molecules, which weakens the spherical effect of planetary atmosphere. Hn variations, especially the longitudinal variation associated with non-migrating tides, are important factors responsible for the NmM2 deviation from the Chapman theory. Statistically, they can cause ∼1.4% average deviation for the condition of the MGS RO measurement. An effective modification method based on available Hn was correspondingly suggested to promote the accuracy of NmM2 estimation based on the Chapman theory. It is notable that Hn variations do not show evident contribution to NmM2 deviation from the Chapman theory in the southern hemisphere, where the stronger crustal magnetic fields likely have dominant contribution to the NmM2 deviation as compared with Hn variations.

Analysis of ionospheric parameters retrieved from Feng-Yun 3C and COSMIC radio occultation

Electron density profiles observed using Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) and Feng-Yun 3C (FY3C) radio occultation (RO) missions from 2014 to 2018 were quality inspected and analysed. After eliminating observations that did not meet the quality requirements, we compared the critical frequency of the F2 layer (foF2) and total electron content (TEC) with data retrieved from ionosondes and global ionospheric maps (GIM). Results showed that the quality of the COSMIC and FY3C RO electron density profiles was higher during the daytime compared to that overnight and was better in summer and autumn compared to spring and winter. Furthermore, the electron density profile qualification rate was higher for FY3C RO than that for COSMIC RO in low latitude regions. The foF2 RO data correlated well with ionosonde data (0.94 and 0.90 for FY3C and COSMIC, respectively). Similarly, TEC RO data correlated well with data from GIM (0.95 and 0.92 for FY3C and COSMIC, respectively). The observation accuracy of the RO data was affected by both solar and geomagnetic activity, and the influence of solar activity was greater than that of geomagnetic activity. During periods of reduced solar and geomagnetic activity, the accuracy of foF2 and TEC retrieved from RO was dependent on the local time, season, and latitude.

Validation of CSES RO measurements using ionosonde and ISR observations

The radio occultation (RO) measurements obtained by GOR payload on board the CSES (the first China Seismo-Electromagnetic Satellite) satellite are validated using the observations from five ionosonde stations located at different latitudes and one incoherent scatter radar (ISR) observatory located at mid-latitude. CSES RO peak values (NmF2) and peak heights (hmF2) are compared with the corresponding measurements from the five ionosonde stations, and RO electron density profiles (EDP) are compared with the corresponding ISR measurements. The results show that: (1) CSES RO NmF2 measurements are generally very consistent with that from ionosondes with a correlation coefficient of 0.9448. Obvious underestimation and overestimation are shown for the daytime NmF2 measurements obtained at and near EIA (Equatorial Ionization Anomaly) crest regions, and different error variation patterns are shown: the error at the EIA peak region increases with increase of the observations, while the error at the region near the EIA crest is almost a constant. Attention should be paid to these daytime measurements obtained at and near EIA region in applications. (2) CSES RO hmF2 measurements are in good agreement with that from ionosondes with a correlation coefficient of 0.8357. There is a tendency the daytime hmF2s are overestimated and the nighttime hmF2s are underestimated. (3) CSES RO EDP measurements generally show good consistency with that from ISR measurements. The RO measurements obtained within the peak height range (200–400 km) have the best performance, but errors increase out of this altitudes range. The error for the altitude of the E layer is relatively large, therefore RO measurements are less reliable for this altitude.

Recovery and Validation of Mars Ionospheric Electron Density Profiles from Viking Orbiter Radio Occultation Observations

Abstract The Viking Orbiter radio occultation experiment acquired vertical profiles of electron density in the ionosphere of Mars. As these profiles were not archived, they were thought to have been lost. Here, we report the recovery and validation of the complete set of high-quality, dayside electron density profiles from Viking Orbiters 1 and 2. Sixty-nine profiles spanning solar zenith angles of 50°–95° were deemed acceptable for scientific analysis. Relative to the widely used set of radio occultation electron density profiles from Mars Global Surveyor, these Viking profiles have better sensitivity, higher vertical extent, more global coverage, and greater solar zenith angle coverage. They are ready for use in scientific investigations of the ionosphere of Mars and related topics. They accompany this article as supplemental information.

Variability of the Martian ionosphere from the MAVEN Radio Occultation Science Experiment

The Martian ionosphere is produced by a number of controlling processes, including solar extreme ultraviolet radiation (EUV) and X-ray ionization, impact ionization by precipitating electrons, and day-to-night transport. This study investigates the structural variability of the Martian ionosphere with the aid of the radio occultation (RO) experiments made on board the recent Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. On the dayside, the RO electron density profiles are described by the superposition of two Chapman models, representing the contributions from both the primary layer and the low-altitude secondary layer. The inferred subsolar peak electron densities and altitudes are 1.24×105 cm–3 and 127 km for the former, and 4.28×104 cm–3 and 97 km for the latter, respectively, in general agreement with previous results appropriate for the low solar activity conditions. Our results strengthen the role of solar EUV and X-ray ionization as the driving source of plasma on the dayside of Mars. Beyond the terminator, a systematic decline in ionospheric total electron content is revealed by the MAVEN RO measurements made from the terminator crossing up to a solar zenith angle of 120°. Such a trend is indicative of day-to-night plasma transport as an important source for the nightside Martian ionosphere.

First Ionospheric Results From the MAVEN Radio Occultation Science Experiment (ROSE)

AbstractRadio occultation observations of the ionosphere of Mars can span the full vertical extent of the ionosphere, in contrast to in situ measurements that rarely sample the main region of the ionosphere. However, most existing radio occultation electron density profiles from Mars were acquired without clear context for the solar forcing or magnetospheric conditions, which presents challenges for the interpretation of these profiles. Here we present 48 ionospheric electron density profiles acquired by the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) Radio Occultation Science Experiment (ROSE) from 5 July 2016 to 27 June 2017 at solar zenith angles of 54° to 101°. Latitude coverage is excellent, and comprehensive context for the interpretation of these profiles is provided by other MAVEN instruments. The profiles show a 9‐km increase in ionospheric peak altitude in January 2017 that is associated with a lower atmospheric dust storm, variations in electron densities in the M1 layer that cannot be explained by variations in the solar soft X‐ray flux, and topside electron densities that are larger in strongly magnetized regions than in weakly magnetized regions. MAVEN Radio Occultation Science Experiment electron density profiles are publicly available on the NASA Planetary Data System.

Observations of the Weddell Sea Anomaly in the ground-based and space-borne TEC measurements

The Weddell Sea Anomaly (WSA) is a summer ionospheric anomaly, which is characterized by a greater nighttime ionospheric density than that in daytime in the region near the Weddell Sea. We investigate the WSA signatures in the ground-based TEC (vertical total electron content) by using GPS and GLONASS measurements of the dense regional GNSS networks in South America. We constructed the high-resolution regional TEC maps for December 2014–January 2015. The WSA effects of the TEC exceed the noontime values are registered starting from 17 LT, it reaches its maximum at 01–05 LT and starts to disappear after 09 LT. Maximal TEC enhancements were as large as a factor of 2.5–3.5 and were registered at 03–04 LT. This effect was mainly localized in the geographical region of 55°S-75°S latitude and 80°W-30°W longitude, close to the Antarctic Peninsula. Further, we examined the WSA occurrence in the topside ionosphere by using GPS measurements from a zenith-looking GPS antenna on board three Swarm satellites to determine topside TEC (above ∼500 km altitude) at the topside ionosphere-plasmasphere system. Global maps of the topside TEC indicated that the zone with significant WSA effect in the topside TEC (TEC increase ∼2–4 times the noontime level) had a large spatial extent over southern Pacific and Atlantic Ocean. It was observed around 150°W-20°W and between 40°S and 70°S during 23 LT - 06 LT. For the first time, the WSA signatures were shown in the topside TEC data derived from the GPS measurements onboard the Swarm constellation. Independently, two other instruments - FORMOSAT-3/COSMIC radio occultation electron density profiles and in situ measurements by the Langmuir Probe instrument onboard Swarm satellites – were able to confirm: (1) the same location of the WSA zone as revealed in Swarm TEC; (2) the most-pronounced WSA effect, as a maximal electron density exceed over the noontime values, corresponds to altitudes above 400–500 km.

Electron densities in the ionosphere of Mars: A comparison of MARSIS and radio occultation measurements

AbstractRadio occultation electron densities measurements from the Mariner 9 and Viking spacecraft, which orbited Mars in the 1970s, have recently become available in a digital format. These data are highly complementary to the radio occultation electron density profiles from Mars Global Surveyor, which were restricted in solar zenith angle and altitude. We have compiled data from the Mariner 9, Viking, and Mars Global Surveyor radio occultation experiments for comparison to electron density measurements made by Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), the topside radar sounder on Mars Express, and MARSIS‐based empirical density models. We find that the electron densities measured by radio occultation are in generally good agreement with the MARSIS data and model, especially near the altitude of the peak electron density but that the MARSIS data and model display a larger plasma scale height than the radio occultation profiles at altitudes between the peak density and 200 km. Consequently, the MARSIS‐measured and model electron densities are consistently larger than radio occultation densities at altitudes ~200–300 km. Finally, we have analyzed transitions in the topside ionosphere, at the boundary between the photochemically controlled and transport‐controlled regions, and identified the average transition altitude, or altitude at which a change in scale height occurs. The average transition altitude is ~200 km in the Mariner 9 and Viking radio occultation profiles and in profiles of the median MARSIS radar sounding electron densities.

A long-term study on the deletion criterion of questionable electron density profiles caused by ionospheric irregularities – COSMIC radio occultation technique

The crucial assumption made in the retrieval of radio-occultated atmospheric parameters is the spherical symmetry of the atmospheric refractive index, which implies that no horizontal gradient of the refractive index exists along the spherical shell. Nevertheless, the presence of density irregularities will lead to scintillation and multipath effects that often create highly fluctuating and random electron density profiles. In this study, it is proposed a reliable data quality control (QC) approach to remove questionable electron density profiles (due to the presence of ionospheric irregularities) retrieved using the COSMIC radio occultation (RO) technique based on two parameters, namely, the gradient and fluctuation of the topside density profile. Statistics of seven years density profiles (July 2006–May 2013) are presented by determining the aforementioned parameters for every density profile. The main advantage of this data QC is that it uses COSMIC RO electron density profiles retrieved from the slant total electron content (TEC) that is estimated from the excess phases of the GPS L1 and L2 frequencies only to delete the questionable profiles, instead of relying on any model and other observations. A systematic criterion has been developed based on the statistics to relinquish the so-called questionable density profiles. The computed gradients and fluctuations of the topside ionosphere electron density profiles have shown a few important features including, solar activity dependency and pronounced variations in between around +40° and −40° latitudes. After the removal of questionable profiles, both peak densities and heights of the ionosphere F layer are presented globally in different seasons of years during 2007 and 2012 that revealed several important features.

Response of the Mars ionosphere to solar flares: Analysis of MGS radio occultation data

AbstractIncreased soft X‐ray irradiance during solar flares produces increased electron densities in the lower ionosphere of Mars, and the relative changes in electron density during a flare are greater for lower altitudes and larger flares. However, this relationship has not been quantified. This has impeded the validation of simulations of the ionospheric response to flares, which are necessary for developing accurate descriptions of the physical processes governing ionospheric behavior under extreme conditions. Here we develop a response function, a mathematical expression for the change in electron density during a solar flare as a function of the change in solar flux and an optical depth proxy. This function is based on analysis of 20 Mars Global Surveyor (MGS) radio occultation electron density profiles measured during solar flares. We find that characterizing the response as a function of optical depth, rather than altitude, provides the best description of ionospheric variability during a flare. A separate response function, determined from analysis of a numerical simulation of the response to a solar flare, was found to be grossly similar to the observationally based response function, though with a weaker dependence on optical depth. We identify 15 MGS profiles with an apparent solar flare response, but no coincident detected solar flare. We suggest that the observed response function can be used to detect flares not visible from Earth and to give an approximation of their strength. Additionally, it can estimate ionospheric electron densities during a flare; however, precision is limited by a small number of observations.

An improved inversion for FORMOSAT‐3/COSMIC ionosphere electron density profiles

AbstractAn improved method to retrieve electron density profiles from Global Positioning System (GPS) radio occultation (RO) data is presented and applied to Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations. The improved inversion uses a monthly grid of COSMIC F region peak densities (NmF2), which are obtained via the standard Abel inversion, to aid the Abel inversion by providing information on the horizontal gradients in the ionosphere. This lessens the impact of ionospheric gradients on the retrieval of GPS RO electron density profiles, reducing the dominant error source in the standard Abel inversion. Results are presented that demonstrate the NmF2 aided retrieval significantly improves the quality of the COSMIC electron density profiles. Improvements are most notable at E region altitudes, where the improved inversion reduces the artificial plasma cave that is generated by the Abel inversion spherical symmetry assumption at low latitudes during the daytime. Occurrence of unphysical negative electron densities at E region altitudes is also reduced. Furthermore, the NmF2 aided inversion has a positive impact at F region altitudes, where it results in a more distinct equatorial ionization anomaly. COSMIC electron density profiles inverted using our new approach are currently available through the University Corporation for Atmospheric Research COSMIC Data Analysis and Archive Center. Owing to the significant improvement in the results, COSMIC data users are encouraged to use electron density profiles based on the improved inversion rather than those inverted by the standard Abel inversion.

First observations of poleward large‐scale traveling ionospheric disturbances over the African sector during geomagnetic storm conditions

AbstractThis paper presents first observations of poleward traveling ionospheric disturbances (TIDs) during strong geomagnetic conditions over the African sector. By analyzing different data sets we have observed both positive and negative ionospheric responses during the storm period of 08–10 March 2012. Considering the African region as a whole, three longitudinal sectors were strategically selected to establish the entire regional response. On both sides of the geomagnetic equator, results show poleward shift in peak total electron content (TEC) enhancements/depletions at different times which are associated to large‐scale TIDs. The observed phenomena are linked to the global ionospheric response and electrodynamics. The understanding has been established using data from International GNSS Service receiver network, radio occultation electron density profiles, derived E×B drift measurements from magnetometer observations and regional ground‐based and satellite data. Contrary to other related studies, generated regional TEC perturbation maps were not enough to show obvious directions of the large‐scale TIDs due to insufficient data over the northern hemispheric part of the African sector. There appears to be a switch between positive and negative storm phases during the same storm period especially in the Southern Hemisphere part of the African region where “enough” data were available. However, a detailed analysis revealed that the positive storm phase corresponded to the expansion of the equatorial ionization anomaly (EIA) toward some parts of midlatitude regions (and possibly with the contribution from low‐latitude electrodynamics associated to equatorial electrojet), while the other part recorded a negative storm phase due to storm‐induced changes from the auroral origin. We have observed a simultaneous occurrence of both poleward and equatorward propagating TIDs over the African sector during the same geomagnetic storm period. Our results show that short‐lived large‐scale TIDs are possibly launched by the equatorial electrojet, while the EIA expansion contributes (through modulation) to the poleward propagation of the disturbances. Temporal variation of TEC perturbations on a storm day over the entire African sector showed the existence of large‐scale TIDs during the main and recovery phases which can travel poleward up to 20° latitude. The amplitudes of the TIDs have range ±2 total electron content unit, 1 TECU = 1016 el m−2, period of 2 h and virtual velocities of 250 ± 59–750 ± 95 m/s in midlatitude regions and up to 990 ± 65 m/s within the EIA region.

Ionosphere equatorial ionization anomaly observed by GPS radio occultations during 2006–2014

A large number of Global Position System (GPS) radio occultation (RO) observations have been accumulated in the University Corporation for Atmospheric Research (UCAR) Constellation Observation System for Meteorology, Ionosphere and Climate (COSMIC) Data Analysis and Archive Center (CDAAC) especially since the launch of COSMIC mission. This study made use of these RO data to study the morphology of ionosphere equatorial ionization anomaly (EIA) statistically during 2006–2014. The ionospheric peak density (NmF2) and peak height (hmF2) derived from the RO electron density profiles as well as the derived magnetic latitude of both crests and trough, the trough width, and the crest-to-trough ratio (CTR) of NmF2 are analyzed systematically. The corresponding seasonal, local time, and solar activity variations and the hemispheric asymmetry are identified and discussed. Most morphology agree well with previous studies and could be explained by the corresponding variations of neutral wind/composition and ExB vertical drift. We also found some interesting features. During May–August, magnetic latitude of the trough could be up to ~5° north of the equator especially around noontime, and the local time difference corresponding best developed EIA between both hemispheres could be up to ~6h. Both crests even move equator-ward with the increase of solar activity in the morning sector except June solstice.

A technique for routinely updating the ITU-R database using radio occultation electron density profiles

Well credited and widely used ionospheric models, such as the International Reference Ionosphere or NeQuick, describe the variation of the electron density with height by means of a piecewise profile tied to the F2-peak parameters: the electron density,\(N_m \mathrm{F2}\), and the height, \(h_m \mathrm{F2}\). Accurate values of these parameters are crucial for retrieving reliable electron density estimations from those models. When direct measurements of these parameters are not available, the models compute the parameters using the so-called ITU-R database, which was established in the early 1960s. This paper presents a technique aimed at routinely updating the ITU-R database using radio occultation electron density profiles derived from GPS measurements gathered from low Earth orbit satellites. Before being used, these radio occultation profiles are validated by fitting to them an electron density model. A re-weighted Least Squares algorithm is used for down-weighting unreliable measurements (occasionally, entire profiles) and to retrieve \(N_m \mathrm{F2}\) and \(h_m \mathrm{F2}\) values—together with their error estimates—from the profiles. These values are used to monthly update the database, which consists of two sets of ITU-R-like coefficients that could easily be implemented in the IRI or NeQuick models. The technique was tested with radio occultation electron density profiles that are delivered to the community by the COSMIC/FORMOSAT-3 mission team. Tests were performed for solstices and equinoxes seasons in high and low-solar activity conditions. The global mean error of the resulting maps—estimated by the Least Squares technique—is between \(0.5\times 10^{10}\) and \(3.6\times 10^{10}\) elec/m\(^{-3}\) for the F2-peak electron density (which is equivalent to 7 % of the value of the estimated parameter) and from 2.0 to 5.6 km for the height (\(\sim \)2 %).

Remote sensing of mars' ionosphere and solar wind interaction: Lessons from venus

Although the PHOBOS spacecraft will make some limited in-situ measurements of Mars' upper ionosphere during its transfer orbits, the major part of the mission will be limited to remote sensing by radio occultation and topside sounding methods. To “calibrate” the former as a means of studying the ionosphere and solar wind interaction, we have examined the Pioneer Venus Orbiter radio occultation experiment results in light of what we know from in-situ plasma and magnetic field data. This “calibration” can be used to reassess the data from previous Mars missions and to provide a basis for interpreting data from the upcoming PHOBOS mission. The resemblance between the available Mars radio occultation electron density profiles and those of Venus at solar minimum, and at solar maximum when the solar wind dynamic pressure is high, suggest that similar conditions of ionospheric magnetization exist at both planets. A key observation by the PHOBOS radio science experiments, which can be used to infer whether this ionospheric field is intrinsic or arises from the solar wind interaction, will be a determination of the sensitivity of the ionospheric profiles to varying solar wind conditions.

Electron precipitation and related aeronomy of the Jovian thermosphere and ionosphere

Voyager ultraviolet spectrometer (UVS) measurements provided the first unassailable evidence for particle precipitation in the Jovian atmosphere. Strong Lyman and Werner band emissions at high latitudes indicate particle precipitation energy fluxes of about 10 ergs cm−2 s−1. On the other hand dayglow Lyman and Werner emissions at mid‐ and low‐latitudes may indicate additional particle precipitation fluxes on the order of 0.3 ergs cm−2 s−1 at all latitudes. Such particle precipitation can have significant aeronomical effects on the Jovian thermsophere and ionosphere. A one‐dimensional theoretical model is used to study these effects for the case of electron precipitation, although ion precipitation produces similar effects. Diffusion equations are solved for all the major neutral species and for H+, and photochemical solutions are given for the short lived ions. These neutral and ionospheric components of the model are coupled with the electron and ion energy equations and a two‐stream electron transport code that calculates the energy deposition of precipitating electrons (considered to be the precipitating particles) and photoelectrons. An independent calculation of the vertical neutral temperature is also obtained. The results of the model calculations can be broadly categorized as effects of electron precipitation (1) on the neutral composition and temperature of the thermosphere, and (2) on the composition and structure of the ionosphere. Auroral electron precipitation by 10‐keV electrons with a total energy flux of 10 ergs cm−2 s−1 produces 4.7×1011 H atoms cm−2 s−1 and 5 ergs cm−2 s−1 of heat, over 2 orders of magnitude larger than solar EUV processes that produce 3.3×109 H atoms cm−2 s−1 and 0.03 ergs cm−2 s−1 of heat. Thus, Jovian auroral H production coupled with aurorally driven meridional winds in the thermosphere can possibly explain the high concentration of atomic hydrogen in the low‐latitude Jovian upper atmosphere. Furthermore, aurorally produced changes in composition can create important feedback which affects the relative airglow efficiencies and heating rates in the high‐latitude thermosphere. In addition, ionization and vibrational heating of H2 from precipitation processes appear to play a central role in determining the structure of the high‐latitude ionosphere. Theoretical fits to the Voyager radio occultation electron density profiles at high latitudes suggest a 10‐keV electron aurora with an energy flux of 10 ergs cm−2 s−1 coupled with a height‐dependent H2 vibrational temperature that reaches 3000 K in the topside ionosphere.