A5051383941- Ionosphere and magnetosphere dynamics
- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Meteorological Phenomena and Simulations
- Climate variability and models
- Atmospheric Ozone and Climate
- Inertial Sensor and Navigation
- Energy Load and Power Forecasting
- Market Dynamics and Volatility
- Atmospheric aerosols and clouds
- Financial Risk and Volatility Modeling
- Reservoir Engineering and Simulation Methods
- Tropical and Extratropical Cyclones Research
- Astrophysics and Cosmic Phenomena
- Radio Wave Propagation Studies
- Target Tracking and Data Fusion in Sensor Networks
- Semiconductor materials and devices
- Stellar, planetary, and galactic studies
- Infrastructure Resilience and Vulnerability Analysis
- Radio Astronomy Observations and Technology
- Risk and Portfolio Optimization
- Insurance, Mortality, Demography, Risk Management
University of Birmingham
2016-2025
Met Office
2023
Qinetiq (United Kingdom)
2013
Abstract In this study, we use measurements from over 4,735 globally distributed Global Navigation Satellite System receivers to track the progression of traveling ionospheric disturbances (TIDs) associated with 15 January 2022 Hunga Tonga‐Hunga Ha'apai submarine volcanic eruption. We identify two distinct Large Scale (LSTIDs) and several subsequent Medium (MSTIDs) that propagate radially outward eruption site. Within 3,000 km epicenter, LSTIDs >1,600 wavelengths are initially observed...
Abstract Severe space weather was identified as a risk to the UK in 2010 part of wider review natural hazards triggered by societal disruption caused eruption Eyjafjallajökull volcano April that year. To support further assessment government officials, and at their request, we developed set reasonable worst‐case scenarios first published them technical report 2012 (current version 2020). Each scenario focused on environment could disrupt particular national infrastructure such electric power...
Abstract The high latitude ionospheric evolution of the May 10‐11, 2024, geomagnetic storm is investigated in terms Total Electron Content and contextualized with Incoherent Scatter Radar ionosonde observations. Substantial plasma lifting observed within initial Storm Enhanced Density plume peak heights increasing by 150–300 km, reaching levels up to 630 km. Scintillation cusp during expansion phase storm, spreading across auroral oval thereafter. Patch transport into polar cap produces...
Quasilinear theories have been shown to well describe a range of transport phenomena in magnetospheric, space, astrophysical and laboratory plasma “weak turbulence” scenarios. It is known that the resonant diffusion quasilinear theory for case uniform background field may formally particle dynamics when electromagnetic wave amplitude growth rates are sufficiently “small”, bandwidth “large”. However, it important note given spectrum would be expected give rise transport, indeed apply...
Abstract Increasing carbon dioxide concentrations in the mesosphere and lower thermosphere are increasing radiative cooling upper atmosphere, leading to thermospheric contraction decreased neutral mass densities at fixed altitudes. Previous studies of historic density trend have shown a dependence upon solar activity, with larger F10.7 values resulting reductions. To investigate impact on future thermosphere, Whole Atmosphere Community Climate Model ionosphere extension has been used...
Abstract A new one‐dimensional variational (1D‐Var) retrieval method for ionospheric GNSS radio occultation (GNSS‐RO) measurements is described. The forward model implicit in the calculates bending angles produced by a electron density profile, modeled with multiple “Vary‐Chap” layers. It demonstrated that gradient based minimization techniques can be applied to this problem. use of discussed. This approach circumvents need Differential Code Bias (DCB) estimates when using measurements. new,...
Abstract In May 2024, a series of coronal mass ejections resulted in the first “severe” (G4‐level) geomagnetic storm watch nearly 20 years. This event evolved into significant space weather event, including an “extreme” (G5) storm, moderate (S2) solar radiation and strong (R3) radio blackout. The widespread visibility auroras at unusually low latitudes attracted global media attention. Using extreme value theory (EVT), this study estimates return periods for 2024 based on several indices....
Quasilinear diffusion coefficients can be used to characterise the statistical response of charged particles perturbations by plasma waves, via resonant wave-particle interactions. The calculation these is sufficiently complicated and arduous render it prohibitive many potential users, because expense in time spent developing code. We present describe open-source PIRAN software package ('Particles In ResonANce'). This written using Python, has comprehensive documentation, allows user...
Abstract This paper describes the construction and use of “modified Taylor diagrams” comparison three real‐time assimilative ionospheric models. The expands on work by McNamara et al. (2013) serves as an addendum to that work. Modified diagrams provide easy way visualizing comparing statistical information about a number models, for multiple parameters, simultaneously. Using modified has led new conclusions models tested in (2013); also, data ingestion version NeQuick is included. It shown...
Abstract By their very nature, extreme space weather events occur rarely, and therefore, statistical methods are required to determine the probability of occurrence. Space can be characterized by a number natural phenomena such as X‐ray (solar) flares, solar energetic particle fluxes, coronal mass ejections, various geophysical indices (such Dst, Kp, F10.7). In this paper value theory (EVT) is used investigate flares. Previous work has assumed that distribution flares follows power law....
The Advanced Ensemble electron density (Ne) Assimilation System (AENeAS) is a new data assimilation model of the ionosphere/thermosphere. background provided by Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM) and uses local ensemble transform Kalman filter (LETKF). An outline derivation LETKF equations are presented in form analogous to classic filter. enhancement efficient implementation reduce computational cost also described. In 3 day test June 2017, AENeAS...
Ionogram data from the Global Ionospheric Radio Observatory (GIRO), processed with Automatic Real-Time Scaler With True Height (ARTIST), is provided confidence scores to guide users on reliability of set.Here we use manually assess extent which these have value and provide guidelines how best apply when filtering GIRO data.It found that score for a given ionospheric parameter (foF1, foF2, or hmF2) not necessarily highest score, depends heavily in question.In addition this demonstrate an...
Abstract Multi‐model ensembles (MMEs) are used to improve the forecasts of thermospheric neutral densities. A variety algorithms for constructing model weights MMEs described and have been implemented including: performance weighting, independence non‐negative least squares. Using both empirical physics‐based models, compared against in situ Challenging Minisatellite Payload (CHAMP) observations, skill each MME weighting approach has tested solar minimum maximum conditions. In cases performs...
Statistical models of the variability plasma in topside ionosphere based on Swarm data have been developed “Swarm Variability Ionospheric Plasma” (Swarm-VIP) project within European Space Agency’s Swarm+4D-Ionosphere framework. The can predict electron density, its gradients for three horizontal spatial scales – 20, 50 and 100 km along North-South direction level density fluctuations. Despite being by leveraging data, provide predictions that are independent these having a global coverage,...
Observations made using the LOw-Frequency ARray (LOFAR) between 10:15 and 11:48 UT on 15th of September 2018 over a bandwidth approximately 25–65 MHz contain discrete pseudo-periodic features ionospheric origin. These occur within period 10 min collectively last roughly an hour. They are strongly frequency dependent, broadening significantly in time towards lower frequencies, show overlaid pattern diffraction fringes. By modelling ionosphere as thin phase screen containing wave-like...
Accurate forecasts of thermosphere densities, realistic calculation aerodynamic drag, and propagation the uncertainty on predicted orbit positions are required for conjunction analysis collision avoidance decision making. The main focus Committee Space Research (COSPAR) International Weather Action Teams (ISWAT) involved in atmosphere variability studies is satellite this paper reviews our current capabilities lists recommendations. density models due to combined effect employing simplified...
Abstract. The standard approach to remove the effects of ionosphere from neutral atmosphere GPS radio occultation measurements is estimate a corrected bending angle combination L1 and L2 angles. This known result in systematic errors an extension has been proposed ionospheric correction that dependent on squared ∕ difference scaling term (κ). variation κ with height, time, season, location solar activity (i.e. F10.7 flux) investigated by applying 1-D operator electron density profiles...
This work presents statistical models of the variability plasma in topside ionosphere based on observations made by European Space Agency’s (ESA) Swarm satellites. The were developed “Swarm Variability Ionospheric Plasma” (Swarm-VIP) project within Swarm+4D-Ionosphere framework. configuration satellites, their near-polar orbits and data products developed, enable studies spatial at multiple scale sizes. modelling technique Generalised Linear Modelling (GLM) was used to create both electron...
Categorizing geomagnetic storms on a scale of one to five leaves no room for once-a-century superstorms.
Abstract. This paper presents the first known application of multi-model ensembles to forecasting thermosphere. A ensemble (MME) is a method for combining different, independent models. The main advantage using an MME reduce effect model errors and bias, since it expected that will, at least partly, cancel. MME, with its reduced uncertainties, can then be used as initial conditions in physics-based thermosphere forecasting. should increase forecast skill reduction generally increases skill....
In this study, we use measurements from over 4,735 globally distributed Global Navigation Satellite System (GNSS) receivers to track the progression of travelling ionospheric disturbances (TIDs) associated with 15 January 2022 Hunga Tonga-Hunga Ha’apai submarine volcanic eruption. We identify two distinct Large Scale TIDs (LSTIDs) and several subsequent Medium (MSTIDs) that propagate radially outward eruption site. Within 3000 km epicenter, LSTIDs >1600 ~1350 wavelengths are initially...
Abstract Here, we assess to what extent the Empirical Canadian High Arctic Ionospheric Model (E‐CHAIM) can reproduce climatological variations of vertical Total Electron Content (vTEC) in sector. Within auroral oval and polar cap, E‐CHAIM is found exhibit Root Mean Square (RMS) errors vTEC as low 0.4 TECU during solar minimum summer but high 5.0 maximum equinox conditions. These represent an improvement up 8.5 over International Reference Ionosphere (IRI) same region. At sub‐auroral...
Abstract The solar radio flux at 10.7 cm, known as F10.7, is a critical operational space weather index. However, without clear backup, any interruption to the service can result in substantial errors model outputs. In this paper we show impact of one such outage March 2022 on models TIE‐GCM and NeQuick, present number alternative solutions that could be used for future outages. analysis extended F10.7 time series since 1951 approach resulting smallest reconstruction error uses observations...
Abstract This paper describes and compares two real‐time assimilative ionospheric models, with an emphasis on their ability to provide accurate profiles of the electron density below peak F2 layer at a midlatitude location, given automatically processed vertical incidence ionograms single location. The models are specifically oriented toward several important practical applications high‐frequency (HF) radio propagation: HF communications, station location transmitters, coordinate...
Abstract In this paper extreme value theory (EVT) has been used to estimate the return levels for geomagnetic activity based on aa index. The index is longest, continuously recorded, data set (from 1868 present). This long, 150‐year an ideal candidate analysis. However, are not independent and identically distributed as required EVT since they impacted by approximately 11‐year solar cycle. Hilbert‐Huang transform identify cycle component in data, have split into maximum minimum times. these...