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A new technique has been developed to determine the high‐latitude electric potential from observed field‐aligned currents (FACs) and modeled ionospheric conductances. FACs are observed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE), while the conductances are modeled by Sami3 is Also a Model of the Ionosphere (SAMI3). This is a development of the Magnetosphere‐Ionosphere Coupling approach first demonstrated by Merkin and Lyon (2010),https://doi.org/10.1029/2010ja015461. An advantage of using SAMI3 is that the model can be used to predict total electron content (TEC), based on the AMPERE‐derived potential solutions. 23 May 2014 is chosen as a case study to assess the new technique for a moderately disturbed case (min Dst: −36 nT, max AE: 909 nT) with good GPS data coverage. The new AMPERE/SAMI3 solutions are compared against independent GPS‐based TEC observations from the Multi‐Instrument Data Analysis Software (MIDAS) by Mitchell and Spencer (2003), and against Defense Meteorological Satellite Program (DMSP) ion drift data. The comparison shows excellent agreement between the location of the tongue of ionization in the MIDAS GPS data and the AMPERE/SAMI3 potential pattern, and good overall agreement with DMSP drifts. SAMI3 predictions of high‐latitude TEC are much improved when using the AMPERE‐derived potential as compared to Weimer's (2005),https://doi.org/10.1029/2005ja011270model. The two potential models have substantial differences, with Weimer producing an average 77 kV cross‐cap potential versus 60 kV for the AMPERE‐derived potential. The results indicate that the 66‐satellite Iridium constellation provides sufficient resolution of FACs to estimate large‐scale ionospheric convection as it impacts TEC.

 

The polarFregion ionosphere frequently exhibits sporadic variability (e.g., Meek, 1949,https://doi.org/10.1029/JZ054i004p00339; Hill, 1963,https://doi.org/10.1175/1520‐0469(1963)020<0492:SEOLII>2.0.CO;2). Recent satellite data analysis (Noja et al., 2013,https://doi.org/10.1002/rds.20033; Chartier et al., 2018,https://doi.org/10.1002/2017JA024811) showed that the high‐latitudeFregion ionosphere exhibits sporadic enhancements more frequently in January than in July in both the northern and southern hemispheres. The same pattern has been seen in statistics of the degradation and total loss of GPS service onboard low‐Earth orbit satellites (Xiong et al. 2018,https://doi.org/10.5194/angeo‐36‐679‐2018). Here, we confirm the existence of this annual pattern using ground GPS‐based images of TEC from the MIDAS algorithm. Images covering January and July 2014 confirm that the high‐latitude (>70 MLAT)Fregion exhibits a substantially larger range of values in January than in July in both the northern and southern hemispheres. The range of TEC values observed in the polar caps is 38–57 TECU (north‐south) in January versus 25–37 TECU in July. First‐principle modeling using SAMI3 reproduces this pattern, and indicates that it is caused by an asymmetry in plasma levels (30% higher in January than in July across both polar caps), as well as 17% longer O⁺plasma lifetimes in northern hemisphere winter, compared to southern hemisphere winter.

 

Abstract. We present the first observations from a new low-cost obliqueionosonde located in Antarctica. The transmitter is located at McMurdoStation, Ross Island, and the receiver at Amundsen–Scott Station, South Pole.The system was demonstrated successfully in March 2019, with the experimentyielding over 30 000 ionospheric echoes over a 2-week period. These dataindicate the presence of a stable E layer and a sporadic and variableF layer with dramatic spread F of sometimes more than 500 km (in units ofvirtual height). The most important ionospheric parameter, NmF2, validateswell against the Jang Bogo Vertical Incidence Pulsed Ionospheric (VIPIR) ionosonde (observing more than 1000 kmaway). GPS-derived TEC data from the Multi-Instrument Data Analysis Software(MIDAS) algorithm can be considerednecessary but insufficient to predict 7.2 MHz propagation between McMurdoand the South Pole, yielding a true positive in 40 % of cases and a truenegative in 73 % of cases. The success of this pilot experiment at a totalgrant 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.