A5028166969- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- GNSS positioning and interference
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Radar Systems and Signal Processing
- Seismic Waves and Analysis
- Atomic and Subatomic Physics Research
- Atmospheric Ozone and Climate
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Astro and Planetary Science
- Geophysical Methods and Applications
- Industrial Vision Systems and Defect Detection
- Advanced SAR Imaging Techniques
- Radio Astronomy Observations and Technology
- Research in Social Sciences
- Lightning and Electromagnetic Phenomena
- Planetary Science and Exploration
- Target Tracking and Data Fusion in Sensor Networks
- Inorganic and Organometallic Chemistry
- Astrophysics and Cosmic Phenomena
- Soil Moisture and Remote Sensing
- Solar Radiation and Photovoltaics
- Magnetic Field Sensors Techniques
University of Oulu
2015-2025
Swedish Institute of Space Physics
2023
Democritus University of Thrace
2023
South African National Space Agency
2022
Laboratoire de Synthèse Organique
1975
Abstract Solar cycles 24–25 were quiet until a geomagnetic storm with Sym‐H index of −170 nT occurred in late March 2023. On 23–24, Fabry‐Perot interferometer (FPI; 630 nm) Tromsø, Norway, recorded the highest thermospheric wind speed over 500 m/s since 2009. Comparisons magnetometer readings Scandinavia showed that large amount electromagnetic energy was transferred to ionosphere‐thermosphere system. Total electron content maps suggested an enlarged auroral oval and revealed FPI observed...
Abstract. The 233 MHz EISCAT_3D radar system currently under construction in northern Fennoscandia will be able to resolve ionospheric structures smaller than the transmit beam dimensions through use of interferometric imaging. This capability is made possible by modular design and digitization 119 panels with 91 antennas each located at main Skibotn site. array consists a cluster 109 panels, 10 outlier producing unique interferometry baselines. In present study, synthesized incoherent...
Abstract We have carried out a statistical study of neutral atmospheric parameters in the mesosphere‐lower thermosphere (MLT) region, by utilizing simultaneous measurements from EISCAT‐VHF radar and sodium LIDAR collocated near Tromsø, Norway. This focuses on spectral width incoherent scatter (IS) signal, which is function ion‐neutral collision frequency, ion temperature, (equal to temperatures D‐region), mass. Using obtained mass using chemistry model, we estimated frequency 80–100 km...
In May 2024, the most intense geomagnetic storm since 2003 was caused by coronal mass ejections from Sun. It has triggered a surge of interest within international space science community with dedicated workshops and planned special issues. Our study focuses on ionosphere-thermosphere responses in northern polar region based multiple observations ground-based instruments (including EISCAT incoherent scatter radar Svalbard, GNSS TEC receivers, SuperMAG magnetometers, SuperDARN coherent...
The Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) is a dual array of omnidirectional VHF radio antennas located near Kilpisjärvi, Finland. It operated by the Sodankylä Geophysical Observatory. makes extensive use proven LOFAR antenna and digital signal-processing hardware, can act as stand-alone passive receiver, receiver for European Incoherent Scatter (EISCAT) very high frequency (VHF) incoherent scatter radar in Tromsø, or conjunction with other Fenno-Scandinavian experiments. In...
Abstract We use the EISCAT incoherent scatter radar data measured in years 2001–2021 to study statistical characteristics of 1–100 keV electron precipitation at 66.7° MLAT over Tromsø. Peak energies, auroral powers and number fluxes precipitating electrons are derived from density altitude profiles along geomagnetic field line during periods no photoionization. The method allows us include energetic 30–100 electrons, which poorly covered earlier satellite‐based studies. Locations within oval...
Abstract Energetic particle precipitation is the major source of electron production that controls ionospheric Pedersen and Hall conductances at high latitudes. Many studies use empirical formulas to estimate conductances. The spectra measured by Defense Meteorological Satellite Program (DMSP) Special Sensor J are often used as input formulas. In this study, we evaluate during four different types auroral conditions based on 63 conjugate events observed DMSP EISCAT. calculated from data with...
Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, solar wind, and interstellar medium. Normally these observations relatively narrow band. With Low Frequency Array (LOFAR) technology at Kilpisjärvi Atmospheric Imaging Receiver (KAIRA) station in northern Finland we have observed over a 3 octave bandwidth. ``Parabolic arcs'', which were discovered pulsars, can provide precise estimates distance velocity scattering plasma. Here report...
Abstract. The 233 MHz EISCAT_3D radar system currently under construction in northern Fennoscandia will be able to resolve ionospheric structures smaller than the transmit beam dimensions through use of interferometric imaging. This capability is made possible by modular design and digitisation 119 91-antenna panels located at main Skibotn site. array consists a cluster 109 panels, with 10 outlier producing unique interferometry baselines. In present study synthesized incoherent scatter...
Abstract. The present standard EISCAT incoherent scatter experiments are based on alternating codes that decoded in power domain by simple summation and subtraction operations. signal is first digitised then different lagged products calculated real time. Only the saved for further analysis so both original data samples undecoded lost. A fit of plasma parameters can be later performed using recorded products. In this paper we describe a method, which makes use statistical inversion removing...
Abstract The high‐latitude ionosphere‐thermosphere system is strongly affected by the magnetospheric energy input during substorms. In this study, we investigate response of upper thermospheric winds to four substorm events using Fabry‐Perot interferometer at Tromsø, Norway, International Monitor for Auroral Geomagnetic Effects magnetometers, EISCAT radar, and an all‐sky camera. had distinct responses phases. During growth phase, westward acceleration wind was observed in premidnight sector...
Abstract This study presents an improved method to estimate differential energy flux, auroral power and field‐aligned current of electron precipitation from incoherent scatter radar data. The is based on a newly developed data analysis technique that uses Bayesian filtering fit altitude profiles density, temperature, ion temperature observed spectra with high time range resolutions. are inverted the density profiles. Previous high‐time resolution fits have relied raw which calculated...
Abstract. We present here the results of a statistical study ionospheric trough observed in 2003 by means satellite tomography. focus on seasonal morphology occurrence and investigate latitude, width horizontal gradients at edges, different magnetic local times, as well their relations to geomagnetic activity interplanetary field. A effect is noticed diurnal variation indicating that summer clearly differs from other seasons. In winter troughs seem follow solar terminator. The has it depends...
Abstract. A new incoherent scatter (IS) diagnostic technique for the actively heated D-region ionosphere is presented. In this approach, an exponential autocorrelation function (ACF) was fitted to data by using a Markov Chain Monte Carlo (MCMC) inversion and Sodankylä Ion Chemistry model (SIC). The method applied set of combined EISCAT heating VHF radar experiments carried out in November 2006. newly designed experiment, sippi, based on optimised phase codes direct sampling transmitted...
Abstract Multistatic incoherent scatter radars are superior to monostatic facilities in the sense that multistatic systems can measure plasma parameters from multiple directions volumes limited by beam dimensions and measurement range resolution. We propose a new analysis technique uses data all receiver beams of multistatic, multibeam radar system produces, addition typically measured with radars, estimates ion velocity vectors temperature anisotropies. Because total scattered energy...
In the space physics community, processing and combining observational modeling data from various sources is a demanding task because they often have different formats use coordinate systems. The Python package GeospaceLAB has been developed to provide unified, standardized framework process data. composed of six core modules, including DataHub as manager, Visualization for generating publication quality figures, Express higher-level interfaces , SpaceCoordinateSystem system transformations,...
Abstract Ion drag associated with the ionospheric plasma convection plays an important role in high-latitude thermospheric dynamics, yet changes wind geomagnetic activity are not fully understood. We performed a statistical analysis of measurements Fabry–Perot interferometer (FPI; 630 nm wavelength) Tromsø, Norway, winter months for 9 years. The were sorted by SuperMAG (SME) index, and quiet-time pattern was defined as hourly mean under SME ≤ 40 nT. can be expected to represented pressure...
Abstract We present Swarm satellite and EISCAT radar observations of electrodynamical parameters in the midnight sector at high latitudes. The most striking feature is a plasma flow channel located equatorward polar cap boundary within dawn convection cell. 1.5° wide latitude contains southward electric field 150 mV/m, corresponding to eastward velocities 3,300 m/s F ‐region ionosphere. theoretically computed ion temperature enhancement produced by observed velocity accordance with measured...
Abstract Differential energy flux of electrons precipitating into the high‐latitude ionosphere can be estimated from incoherent scatter radar observations ionospheric electron density profile. We present a method called ELSPEC for spectrum estimation measurements, which is based on integration continuity equation and model selection by means Akaike information criterion. This approach allows us to use data with almost arbitrary time resolutions, enables dense grids, avoids noise...
Abstract. We validate two-dimensional ionospheric tomography reconstructions against EISCAT incoherent scatter radar measurements. Our method is based on Bayesian statistical inversion with prior distribution given by its mean and covariance. employ ionosonde measurements for the choice of covariance parameters use Gaussian Markov random fields as a sparse matrix approximation numerical computations. This results in computationally efficient tomographic algorithm clear probabilistic...
Abstract The article proposes a straightforward Kalman filter‐based method for computationally efficient ionospheric electron density multi‐instrument imaging. approach uses direct measurements, such as ionosondes, and general physical assumptions to estimate the uncertainty associated with previous reconstructed time step. Therefore does not require any model of ionosphere background. is represented by an inverse covariance matrix constructed Gaussian Markov random fields, allowing problem...
Abstract This study focuses on the poorly known effect of polar cap patches (PCPs) ion‐neutral coupling in F ‐region. The PCPs were identified by total electron content measurements from Global Navigation Satellite System (GNSS) and ionospheric parameters Defense Meteorological Program spacecraft. EISCAT incoherent scatter radars Svalbard at Tromsø, Norway observed that entered nightside auroral oval became plasma blobs. convection further transported blobs to duskside. Simultaneously,...
Abstract The effect of storms driven by solar wind high‐speed streams (HSSs) on the high‐latitude ionosphere is inadequately understood. We study ionospheric F ‐region during a moderate magnetic storm 14 March 2016 using EISCAT Tromsø and Svalbard radar latitude scans. AMPERE field‐aligned current (FAC) measurements are also utilized. Long‐duration 5‐day electron density depletions (20%–80%) dominant feature outside precipitation‐dominated midnight morning sectors. Depletions found in two...
The mechanism behind the modulation of polar mesospheric winter echoes (PMWE) observed in active HF heating experiments is considered. We propose that negative ion chemistry plays a role heater‐induced PMWEs. In mesosphere, an increased electron temperature leads to higher rate neutral attachment, and therefore decreased density. To first‐order approximation, scattering from Bragg‐scale gradients caused by turbulence can be considered proportional density squared. Under this assumption,...
Abstract. Both ionospheric and weather radar communities have already adopted the method of transmitting pulses in an aperiodic manner when measuring moderately overspread targets. Among users radars, this is called Aperiodic Transmitter Coding (ATC), whereas term Simultaneous Multiple Pulse-Repetition Frequency (SMPRF). When probing ionosphere at carrier frequencies EISCAT Incoherent Scatter Radar facilities, range extent detectable target typically order one thousand kilometers – about...