In this investigation, we present and discuss the effects of the intense geomagnetic storm that occurred in March 2024 on ionospheric electrodynamics and the ionospheric irregularities using observations from SuperDARN radar, magnetometers, equatorial electric field (EEF) model, GPS receivers, Swarm satellites, and ionosondes over American and Antarctic sectors. During the main phase of the storm, there is an increase in cross-polar cap convection reaching ∼58 and ∼68 kV in the Northern and Southern Hemispheres, respectively. EEJ observations show a strong and prolonged interval of negative values, while the EEF measurements indicate eastward/westward directions of the prompt penetration electric field (PPEF). The recovery phase of the storm is dominated by disturbance dynamo electric field (DDEF), which developed ∼1.5 h earlier in the main phase. VTEC values show a positive phase in mid-and low-latitudes in both hemispheres, reaching up to ∼150% at mid-and near high-latitudes and ∼30-60% at equatorial and low-latitudes. The eastern and western sectors show similar pattern. A combination of PPEF and disturbed thermospheric winds generated this positive phase in both sectors and hemispheres. During the recovery phase, the eastern and western sectors exhibit a weak positive and negative ionospheric storms in both Hemispheres, respectively, associated with DDEF. Ionospheric irregularities are observed at high-latitudes only in the Northern Hemisphere, which is characteristic signatures of storm enhanced density (SED) and polar cap patches (PCPs). S4 remained weak, below 0.2-0.3, at mid-and near high-latitudes in the Northern Hemisphere and moderate to strong, reaching 0.5-0.8, at equatorial and lowlatitudes in the Southern Hemisphere, with suppression of irregularities during the night of 03-04 March.

In this study, we analyze ionograms recorded at Malindi (3.1° S, 40.7° E; dipole geom. lat. 6.8° S, Kenya, Africa) and Jataı ´ (17.5° S, 51.4° W; dipole geom. lat. 9.1° S, Brazil, South America) from August 2023 to July 2024 to estimate the ionospheric vertical plasma drift associated with the pre-reversal enhancement (PRE). This is the first time that such an intercontinental comparison based on ionosonde data has been conducted, providing a unique opportunity to investigate the ionospheric behavior across widely separated longitudinal sectors. The most striking result is that between October and March, a clear PRE signature is observed at both stations, even though they lie outside the conventional ±5° geomagnetic latitude equatorial belt typically used in climatological studies and for the development of vertical plasma drift models. This finding suggests that limiting such studies and models to the ±5°belt may significantly constrain our understanding of equatorial ionospheric dynamics. Furthermore, the analysis reveals a suppression of the PRE around the June solstice and a marked intensification between October and March, with the effect more pronounced at Malindi than at Jataı ´. At Malindi, the PRE consistently peaks between 18:00 and 19:00 local time (LT), reaching a maximum value of 30 m/s in October. At Jataı ´, the PRE peaks slightly later, between approximately 18:30 and 19:15 LT, with a maximum value of 20 m/s in January. We compare ionosonde derived vertical drifts at PRE with a recently developed model based on a combination of magnetometer, satellite and incoherent scatter radar observations as well as the empirical model incorporated within the International Reference Ionosphere that was constructed using satellite data.

A digital low power pulse compressed ionosonde was developed at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy. The aim of this Advanced Ionospheric Sounder, AIS-INGV, is to reduce the transmitted power and, consequently, weight, size, power consumption and hardware complexity. To compensate the power reduction the most advanced HF radar techniques such as the pulse compression and a phase coherent integration are used. The ionosonde is completely programmable and a PC supports the data acquisition, control, storage and on-line processing. The first prototype was installed at Gibilmanna Ionospheric Observatory (Sicily), an interesting location in the center of Mediterranean area. The new ionosonde will contribute to ionospheric database and real time knowledge of South European ionospheric conditions for space weather applications. In this work the first results (ionograms and autoscaled characteristics) are presented and briefly discussed.

A new digital ionosonde called AIS-INGV (Advanced Ionospheric Sounder) was designed both for research and for routine service of HF radio wave propagation forecast. Nearly the entire system was developed in the Laboratorio di Geofisica Ambientale at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome. It exploits advanced techniques for signal analysis, recent technological devices and PC resources. This paper describes design concepts and performance of the new ionosonde.

The Italian Ionospheric Antarctic Observatory of Terra Nova Bay (74.70S, 164.11E) was recently equipped with the AIS-INGV ionosonde developed at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, (Italy). This paper aims to describe briefly which are the main characteristics of the instrument and show the good quality and reliability of the recorded ionograms.

The ionosonde is a system which exploits the radar technique: it applies electromagnetic waves with variable frequency in the HF band to measure the ionospheric layers electron density, height and other parameters. This paper is a technical report on the new digital ionosonde (AIS-INGV), which was designed both for research purposes and for the routine service of the HF radiowave propagation forecast. It has been developed almost completely within the Laboratorio di Geofisica Ambientale (LGA) at the Istituto Nazionale di Geofisica e Vulcanologia (INGV). It exploits advanced techniques for the signal analysis, recent technological devices and PC resources. The report is divided into two parts; the first is a general description of the design development, the second is a more detailed description of the blocks and circuits actually built and tested, directed to a specialist reader.