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We present the first observations from a new low-cost oblique ionosonde located in Antarctica. The transmitter is located at McMurdo Station, Ross Island, and the receiver at Amundsen–Scott Station, South Pole. The system was demonstrated successfully in March 2019, with the experiment yielding over 30 000 ionospheric echoes over a 2-week period. These data indicate the presence of a stable E layer and a sporadic and variable F layer with dramatic spread F of sometimes more than 500 km (in units of virtual height). The most important ionospheric parameter, NmF2, validates well against the Jang Bogo Vertical Incidence Pulsed Ionospheric (VIPIR) ionosonde (observing more than 1000 km away). GPS-derived TEC data from the Multi-Instrument Data Analysis Software (MIDAS) algorithm can be considered necessary but insufficient to predict 7.2 MHz propagation between McMurdo and the South Pole, yielding a true positive in 40 % of cases and a true negative in 73 % of cases. The success of this pilot experiment at a total grant cost of USD 116 000 and an equipment cost of ∼ USD 15 000 indicates that a large multi-static network could be built to provide unprecedented observational coverage of the Antarctic ionosphere.

Global Navigation Satellite System (GNSS) signals exhibit rapid fluctuations at high and low latitudes as a consequence of propagation through drifting ionospheric irregularities. We focus on the high latitude scintillation problem, taking advantage of a conjunction of EISCAT Incoherent Scatter Radar (ISR) observations and a GPS scintillation monitor viewing the same line-of-sight. Just after 20:00 UT on 17 October 2013, an auroral E-region ionization enhancement occurred with associated phase scintillations. This investigation uses the scintillation observations to estimate the ionospheric electron density distribution beyond the spatial resolution of the ISR (5 - 15 km along the line-of-sight in this case). Following the approach of Deshpande et al. [2014], signal propagation is modeled through a specified density distribution. A multiple phase screen propagation algorithm is applied to irregularities conforming to the description of Costa and Kelley [1977] and constrained to match the macroscopic conditions observed by the ISR. A 50-member ensemble of modeled outputs is approximately consistent with the observations according to the standard deviation of the phase (σp). The observations have σp = 0.23 radians, while the ensemble of modeled realizations has σp = 0.23 + 0.04 -0.04. By comparison of the model output with the scintillation observations, we show that the density fluctuations cannot be a constant fraction of the mean density. The model indicates that E-region density fluctuations whose standard deviation varies temporally between 5 - 25% of the mean (ISR-observed) density are required to explain the observed phase scintillations.

The impact of space weather events on satellitebasedtechnologies (e.g. satellite navigation and precise positioning)is typically quantified on the basis of the total electroncontent (TEC) and temporal fluctuations associated withit. GNSS (global navigation satellite systems) TEC measurementsare integrated over a long distance and thus may includecontributions from different regions of the ionised atmospherewhich may prevent the resolution of the mechanismsultimately responsible for given observations. The purposeof the experiment presented here was to compare TECestimates from EISCAT and GPS measurements. The EISCATmeasurements were obtained along the same line ofsight of a given GPS satellite observed from Tromsø. Thepresent analyses focussed on the comparison of temporalfluctuations in the TEC between aligned GPS and EISCATmeasurements. A reasonably good agreement was found betweentemporal fluctuations in TEC observed by EISCATand those observed by a co-located GPS ionospheric monitoralong the same line of sight, indicating a contributionfrom structures at E and F altitudes mainly to the total TECin the presence of ionisation enhancements possibly causedby particle precipitation in the nighttime sector. The experimentsuggests the great potential in the measurements to beperformed by the future EISCAT 3D system, limited only inthe localised geographic region to be covered.