Bodo Reinisch

• Professor
• CEO at Lowell Digisonde International LLC

The Peak Density Thickness (PDT) refers to a vertical region in the ionosphere encompassing the F2 peak, where electron density is at its maximum, and extending upward—maintaining a constant density—for a fixed altitude beyond this peak. This study builds on the previously established PDT concept, initially explored at midlatitudes using data from...

This research builds on the previously established Peak Density Thickness (PDT) concept for midlatitudes at Millstone Hill by examining its applicability at equatorial latitudes using data from the Jicamarca Incoherent Scatter Radar (ISR) in Lima, Peru. An 18-hour dataset was meticulously analyzed to capture the F2 layer's PDT parameter with high s...

This paper introduces the Peak Density Thickness (PDT) formalism, a novel approach to representing the F2 layer's vertical electron density profile in the ionosphere. It diverges from the conventional “pointed‐peak” model by suggesting a “broad‐peak” or “flat‐nose” profile where plasma density remains constant within an altitude interval χ. This th...

Artificially enhancing the pitch angle diffusion of the relativistic electrons trapped in the radiation belts with transmission of very‐low frequency (VLF) electromagnetic waves is the primary science objective of the wave‐particle interaction experiments (WPIx) on the Demonstration Science Experiments (DSX) spacecraft. The pitch angle diffusion oc...

Plain Language Summary In this paper, we summarize the Air Force Research Laboratory's Demonstration and Science Experiments (DSX) satellite mission which recently concluded after nearly 2 yr in the radiation belts. We describe the DSX science instruments and how we planned and performed experiments during the mission. The mission had a primary goa...

High‐power transmission experiments in the very low frequency (VLF) mode have been conducted by the US Air Force Research Laboratory’s Demonstration and Science Experiments (DSX) satellite in the radiation belts using a novel transmitter that automatically tunes to find the resonance frequency of the transmitter circuit including the antenna. The r...

Very low frequency (VLF) waves (about 3–30 kHz) in the Earth’s magnetosphere interact strongly with energetic electrons and are a key element in controlling dynamics of the Van Allen radiation belts. Bistatic very low frequency (VLF) transmission experiments have recently been conducted in the magnetosphere using the high-power VLF transmitter on t...

This paper is a review of the International Reference Ionosphere (IRI) project and model. IRI is recognized as the official standard for the Earth's ionosphere by the International Standardization Organization, the International Union of Radio Science, the Committee on Space Research, and the European Cooperation for Space Standardization. As reque...

Space weather phenomena can threaten space technologies. A hazard among these is the population of relativistic electrons in the Van Allen radiation belts. To reduce the threat, artificial processes can be introduced by transmitting very-low-frequency (VLF) waves into the belts. The resulting wave-particle interactions may deplete these harmful ele...

Prompt and accurate imaging of the ionosphere is essential to space weather services, given a broad spectrum of applications that rely on ionospherically propagating radio signals. As the 3D spatial extent of the ionosphere is vast and covered only fragmentarily, data fusion is a strong candidate for solving imaging tasks. Data fusion has been used...

Space weather phenomena threaten the space assets that bring us services via space technologies, such as the Global Positioning System, communication systems with satellite relays, and most global TV broadcast networks, which have provided unprecedented convenience to everyday life and opportunities to businesses. A hazard among phenomena1 is the p...

Images of a spatial region provide the observer a framework with which to recognize and interpret how features can change temporally and spatially. The choice of imaging technique typically depends on the desired information about the target. Traditional imaging techniques typically employ well-defined signals, such as photons or energetic neutral...

The great solar eclipse traveled eastward through the American Continent from coast to coast on August 21, 2017 and provided a rare opportunity to investigate the ionospheric responses to the rapid solar radiation variations. We have analyzed the peak electron density and density gradient variations in Sporadic E (Es) and applied the data of four D...

We modified and justified the radar equation for ground penetration by including the backscattering effect. We propose a strawman system on an orbiter 50 km above the surface based on lunar conditions. The Tightly coupled dipole arrays antenna substantially reduces the size and mass and consists of an array with 8 × 8 cells on a light weight plate...

We treat whistler-mode radiation from a dipole antenna in a cold magnetized plasma based on the Fresnel zone construction theory. Radiated waves from the antenna with different propagation directions interfere in space. Regions of enhanced waves are formed when the interference is predominantly constructive at the observing point. The coherently en...

Non‐linear Error Compensation Technique with Associative Restoration (NECTAR) is a novel approach to the assimilation of fragmentary sensor data to produce a global nowcast of the near‐Earth space weather. NECTAR restores missing information by iteratively transforming (“morphing”) an underlying global climatology model into agreement with currentl...

Recommendations of the International Reference Ionosphere (IRI) Workshop 2017 in Taoyuan City, Taiwan and International GNSS Service (IGS) Workshop 2018 in Wuhan, China included establishment of an ionosphere mapping service that would fuse measurements from two independent sensor networks: IGS permanent GNSS receivers providing the vertical total...

In this paper, we present a systematic study on the characteristics and evolution of the F3 layer using the Jicamarca incoherent scatter radar (ISR) observations made during 2014–2018. These results are also compared with those obtained from collocated digisonde observations in an effort to understand the F3 layer in more detail. The purpose of the...

Traveling Ionospheric Disturbances (TIDs) are wave-like propagating irregularities that alter the electron density environment and play an important role spreading radio signals propagating through the ionosphere. A method combining spectral analysis and cross-correlation is applied to time series of ionospheric characteristics (i.e., MUF(3000)F2 o...

Travelling Ionospheric Disturbances (TIDs) are plasma density fuctuations that propagate as waves through the ionosphere. TIDs constitute a threat for operational systems using predictable ionospheric characteristics as they can impose signicant disturbances in the ambient electron density and Doppler frequency shift on HF signals. TIDs can have ef...

The warning system provides large-(LSTID) and medium-scale (MSTID) TID detection, TID activity indicators, and TID drivers to the user communities.

The existence of an additional stratification in the daytime equatorial ionospheric F region (the F3 layer) was known since the 1940s. However, its characteristics and the underlying physical mechanism have been uncovered only recently. In this paper, we present and discuss the F3 layer characteristics observed by six ionosondes distributed over eq...

One inherent parameter in the extrapolation of ionospheric topside profile is the scale height, which can be derived from an ionogram. For the first time in the African equatorial region, the variation of digisonde‐derived scale height (Hm) is investigated at Ilorin (Geog. 8.50°N; 4.50°E; dip. –7.9°) during quiet and disturbed conditions. Diurnal p...

The equatorial ionosphere often shows the occurrence of plasma-density irregularities and velocity fluctuations with a broad range of scale sizes and amplitudes. These irregularities in the F-region are commonly referred to as the equatorial spread F (ESF) and they are predominantly a night-time phenomenon. The vertical drift of ionisation to highe...

In this paper, we present the preliminary results of a new global three‐dimensional (3‐D) ionospheric model developed using artificial neural networks (ANNs) by assimilating long‐term ionospheric observations from nearly two decades of ground‐based Digisonde, satellite‐based topside sounders, and global positioning system‐radio occultation measurem...

The response of the ionospheric bottomside electron density profile parameters of the F2 layer, namely, the maximum electron density (NmF2), the maximum height of F2 layer (hmF2), and bottomside thickness (B0) parameter to the equatorial electrojet (EEJ) current is examined for a Peruvian location at the Jicamarca station (12 °S, 76.9 °W) in the So...

An artificial neural network-based two-dimensional ionospheric model (ANNIM) that can predict the ionospheric F2-layer peak density (NmF2) and altitude (hmF2) had recently been developed using long-term data of Formosat-3/COSMIC GPS radio occultation (RO) observations (Sai Gowtam & Tulasi Ram, 2017a, https://doi.org/10.1002/2017JA024795). In this c...

Multiple observational studies have demonstrated large ionospheric variations during the daytime associated with sudden stratospheric warming (SSW) events, but only limited evidence of ionospheric disturbances during the nighttime has been reported up to now. We focus on the American longitudinal sector with its extensive observational network of G...

A large number (~1,000) of coincident auroral far ultraviolet (FUV) and ground-based ionosonde observations are compared. This is the largest study to date of coincident satellite-based FUV and ground-based observations of the auroral E region. FUV radiance values from the NASA Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics Global Ult...

A new technique for Travelling Ionospheric Disturbances (TID) identification in near-real time is presented, which is based on the analysis of oblique Digisonde-to-Digisonde (D2D) “skymap” observations for the direct identification of TIDs and the specification of the TID wave parameters. The technique is based on the measurement of angle-of-arriva...

Travelling Ionospheric Disturbances (TIDs) are the ionospheric signatures of atmospheric gravity waves (AGWs). Their identification and tracking is important because the TIDs affect all services that rely on predictable ionospheric radio wave propagation. Although various techniques have been proposed to measure TID characteristics, their real-time...

This paper presents a comparison of modeled and measured electron densities for the August 21, 2017 solar eclipse across the USA. The location of the instrument was (43.81°N, 247.32°E) where the maximum obscuration of 99.6% occurred at 17.53 hours UT on August 21. The solar apparent time was 9.96 hours and the duration of the eclipse was 2.7 hours....

A network of ionosondes in Europe has been established to monitor travelling ionospheric disturbances (TIDs) by simultaneously making vertical and oblique incidence HF sounding measurements. This network is the outcome of the Net-TIDE project, a collaboration between European Digisonde operators that have synchronized the sounding schedules of the...

We connect the time sequence of changes in the IMF-Bz to the development of spread-F at an equatorial station Kwajalein on three different nights in November 2004, one during a geomagnetic quiet period and other two during geomagnetic disturbed periods. The chosen days show clear and smooth variations of IMF-Bz without any large fluctuations thereb...

We used the hourly ionogram data obtained from Jicamarca station (12° S, 76.9° W, dip latitude: 1.0° N) an equatorial region to study the variation of the electron density profile parameters: maximum height of F2-layer (hmF2), bottomside thickness (B0) and shape (B1) parameter of F-layer. The period of study is for the year 2010 (solar minimum peri...

The paper presents the latest version of the International Reference Ionosphere model (IRI-2016) describing the most important changes and improvements that were included with this version and discussing their impact on the IRI predictions of ionospheric parameters. IRI-2016 includes two new model options for the F2-peak height hmF2 and a better re...

In the framework of a new NATO Science for Peace and Security multi-year project (2014-2017) we are exploiting for the first time the European network of high precision ionospheric DPS4D sounders and the related software to directly identify TIDs over Europe and specify in real time the gravity wave parameters based on measuring the variations of t...

The electron density of the topside ionosphere and the plasmasphere contributes essentially to the overall Total Electron Content (TEC) budget affecting Global Navigation Satellite Systems (GNSS) signals. The plasmasphere can cause half or even more of the GNSS range error budget due to ionospheric propagation errors. This paper presents a comparat...

Measuring the time variations of Doppler frequencies and angles of arrival (AoA) of ionospherically reflected HF waves has been proposed as a means of detecting the occurrence of traveling ionospheric disturbances (TIDs). Simulations are made using ray tracing through the International Reference Ionosphere (IRI) electron density model in an effort...

Probing the Sky with Radio Waves: From Wireless Technology to the Development of Atmospheric Science, by Chen-Pang Yeang, reads like a suspense novel. Yet it represents a masterpiece of philosophical and historical significance, displaying intimate knowledge of the technical and scientific subject matter. Probing the Sky with Radio Waves leads us f...

The International Reference Ionosphere (IRI) is recognized as the official standard for the ionosphere (COSPAR, URSI, ISO) and is widely used for a multitude of different applications as evidenced by the many papers in science and engineering journals that acknowledge the use of IRI (e.g., about 11% of all Radio Science papers each year). One of th...

The response of the vertical plasma drift (Vz) and the electron density (NmF2) during different solar eclipses were investigated. The Diurnal values of the direct scaled measurement of F2 peak height and the one derived from M(3000)F2 data, acquired over an equatorial/low-latitude stations have been used to determine the vertical plasma drift. The...

Travelling Ionospheric Disturbances (TIDs) are the ionospheric signatures of atmospheric gravity waves. TIDs carry along information about their sources of excitations which may be either natural (energy input from the auroral region, earthquakes/tsunamis, hurricanes, solar terminator, and others) or artificial (ionospheric modification experiments...

Travelling Ionospheric Disturbances (TIDs) are the ionospheric signatures of atmospheric gravity waves. TIDs carry along information about their sources of excitations which may be either natural (energy input from the auroral region, earthquakes/tsunamis, hurricanes, solar terminator, and others) or artificial (ionospheric modification experiments...

Preliminary measurements by the SWARM Langmuir Probes will be compared with predictions by the International Reference Ionosphere (IRI) (D. Bilitza et al., Journal of Space Weather and Space Climate, 4, 2014, A07(1–12)) involving both the standard IRI and the Real-Time IRI. The Real-Time IRI is based on the IRI Real-Time Assimilative Mapping (IRTAM...

Non-linear Error Compensation Technique for Associative Restoration (NECTAR) is a novel approach to the task of assimilating fragmentary sensor data into a global coverage model, in which an underlying model prediction is iteratively transformed (“morphed”) into a better agreement with the available sensor data. Similarly to the Kalman filter, NECT...

Previous studies have shown that the ionospheric “strong range spread F” (SSF) closely correlates with the occurrence of scintillations caused by equatorial plasma bubbles. However, there is no report on concurrent observations of SSF and bubbles with in situ measurement. This paper discusses two cases of concurrent observations with a DPS4 Digison...

Variations in the evening/nighttime ionosonde vertical plasma drift velocities inferred from the time rate of change of both the base of the F-layer height (Vz(h’F)) and height of the peak electron density (Vz(hmF2)) from an equatorial station were compared for better description of the E x B drifts. For better interpretation, both results were com...

Variations in the evening/nighttime ionosonde vertical plasma drift velocities inferred from the time rate of change of both the base of the F-layer height (Vz(h′F)) and height of the peak electron density (Vz(hmF2)) from an equatorial station were compared for better description of the E×B drifts. For better interpretation, both results were compa...

The effects of some geomagnetic storms on the F2 layer peak parameters over Ilorin, Nigeria (Lat. 8:53°N, Long. 4.5°E, dip angle, −2.96°) have been investigated. Our results showed that the highest intensity of the noon bite-out occurred during the March equinox and lowest during the June Solstice on quiet days. Quiet day NmF2 disturbances which ap...

This laudation is given in honor of the 100th birthday of Prof. Karl Rawer which happens to coincide with the 45th anniversary of the International Reference Ionosphere (IRI). The ionosphere was discovered during Karl Rawer's lifetime, and he has dedicated his professional life to its exploration. World Wars I and II shaped his early life, but they...

In general, it is very difficult to find analytical solutions of the electromagnetic field in an inhomogeneous magnetoplasma such as the ionosphere and magnetosphere, even under the approximation of geometrical optics [Budden, 1988]. As a powerful technique, numerical ray tracing can give solutions in these cases, and it is widely used to reveal th...

We investigated mass density ρm and O+ concentration ηO+≡nO+/ne (where nO+ and ne are the O+ and electron density, respectively) during two events, one active and one more quiet. We found ρm from observations of Alfvén wave frequencies measured by the GOES, and we investigated composition by combining measurements of ρm with measurements of ion den...

Plasmaspheric electron content is, beyond the ionosphere as major source, a significant contributor to the overall TEC budget affecting GNSS signals. The plasmasphere can induce half or more of the GNSS range errors caused by atmospheric electrical charges, in particular at nighttime. At DLR Neustrelitz, Germany, GPS measurements recorded onboard t...

The paper describes the results of spread-F at low latitude stations around the world during the magnetic storm starting at 0130 UT on 22 January 2004. The storm can be divided into two phases, first phase up to 1000 UT when interplanetary magnetic field IMF-Bz was highly fluctuating around a small positive value and the second phase after a sudden...

The Incoherent Scatter Radar measurement over Jicamarca, together with the IRI model-2007 measurements were compared with ground-based digisonde inferred E x B drift over Ilorin in the African region during year of solar minima (F10.7 = 81). Seasonally, Ilorin pre-reversal enhancement (PRE) had peak drift velocities of 7.2, 3.7 and 7.9 m/s for Marc...

The diffusive equilibrium models that are widely used by the space physics community to describe the plasma densities in the plasmasphere are evaluated with field-aligned electron density measurements from the RPI instrument onboard the IMAGE satellite. The original mathematical form of the diffusive equilibrium model was based on the hydrostatic e...

[1] Solar flares are explosive events on the Sun that release energetic particles, X-rays, EUV, and radio emissions that have an almost immediate impact on Earth's ionosphere-thermosphere (IT) system and/or on operational systems that are affected by IT conditions. To assess such impacts, it is key that we know how the ionosphere is modified. An ob...

The relationship between the ground-based inferred vertical E × B drifts, Vz, and the magnetic equatorial electrojet current during the year of solar minima was presented. Both the diurnal and seasonal Vz variations are positively directed during the daytime and negative at nighttime. The evening time pre-reversal enhancement occurs around 19:00 LT...

The International Reference Ionosphere (IRI) project was established jointly by the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) in the late sixties with the goal to develop an international standard for the specification of plasma parameters in the Earth's ionosphere. COSPAR needed such a specification f...

better understanding of the precursor conditions for the instability growth is very important for identifying the causes of day-to-day variability in the equatorial spread F (ESF)/plasma bubble irregularity development. We investigate here the satellite trace (S-trace) in the ionograms, a precursor to the postsunset ESF occurrence, as observed by D...

The nighttime vertical E × B drifts velocities of the F2-region were inferred from the hourly hmF2 values obtained from ionosonde data over an African equatorial station, Ilorin (8.50oN, 4.68oE; dip lat. 2.95o) during period of low solar activity. For each season, the plasma drift Vz is characterized by an evening upward enhancement, then by a down...

The data presented in this work describes the diurnal and seasonal variation in hmF2, NmF2, and the electrojet current strength over an African equatorial station during a period of low solar activity. The F2 region horizontal magnetic element H revealed that the Solar quiet Sq(H) daily variation rises from early morning period to maximum around lo...

[1] The electron-velocity-distribution function was determined to be highly non-Maxwellian and more appropriate to a kappa distribution, with κ ≈ 2.0, near magnetic midnight in the low-latitude magnetosphere just outside a stable plasmasphere during extremely quiet geomagnetic conditions. The kappa results were based on sounder-stimulated Qn plasma...

Electron density profile data obtained from the FORMOSAT-3 radio occultation (RO) measurements over Ascension Island are used to study the bottomside thickness parameter B0 in the International Reference Ionosphere (IRI) model, scale height around the F region peak height, and other F2 region parameters. The RO data were collected when the radio oc...

Average values of ionosonde hmF2 data acquired from an African equatorial station have been used to determine vertical plasma drift (Vz) measurements during period of low solar activity. Pre-noon peak was around 1000 h LT for all seasons. The peak daytime F2 drift is higher during the equinoctial months with an average of 18.1 m/s than the solstici...

Using measured field-aligned electron density profiles, this study investigates the validity of the diffusive equilibrium model in Earth's plasmasphere. This model which describes the electron and ion densities along a magnetic field line in the plasmasphere has been widely used for ray tracing and pitch-angle scattering calculations. It is based o...

Myriametric radio emissions (with wavelengths of 10-100 km) from Earth's magnetosphere have been known to take on different forms. Most notable forms include the classical non-thermal continuum (NTC) with both escaping and trapped components, continuum enhancement (CE), and auroral myriametric radiation (AMR). Continuum radiation emanating from pla...

This paper analyzes the effect of ionospheric refraction on the scattering of high frequency (HF) signals by random field-aligned irregularities in the upper ionosphere. Ray optics calculations are made using the perturbation method for a plane-stratified (on average) ionosphere, i.e., the incident and scattered waves are both supposed to propagate...

This issue of Advances in Space Research presents a selection of papers that document the progress in developing and improving the International Reference Ionosphere (IRI), a widely used standard for the parameters that describe the Earths ionosphere. The core set of papers was presented during the 2010 General Assembly of the Committee on Space Re...

Ionospheric models are mostly unable to correctly predict the effects of space weather events on the ionosphere. This is especially true for the International Reference Ionosphere (IRI) which by design is a monthly median (climatologic) model (Bilitza et al., J. Geodesy, 85, 909-920, 2011). The IRI electron density profile is critically dependent o...