Investigating electron precipitation event characteristics and drivers: Combining BARREL-inspired measurements from Antarctica and Canada

In this study we use narrow-band radio receivers recently installed at St Johns, New Foundland, Canada, and south of the Antarctic Peninsula, in order to support the recent NASA BARREL x-ray balloon campaigns that have taken place in Antarctica. These receivers form part of the wider AARDDVARK network. AARDDVARK receivers can detect near-by perturbations in subionospheric radio wave propagation conditions caused by enhanced ionization in the altitude range 50–90 km. We present the results of an investigation of electron precipitation events in and around January 2013, some of which have simultaneous BARREL x-ray measurements in the same region, and some of which combine near-conjugate observations at St Johns, NFL, with those made in Antarctica. We detect changes in amplitude and phase of fixed-frequency radio transmitters caused by electron precipitation events that can be linked to complementary observations made at Halley of widebeam riometer absorption, or VLF wave occurrence, or the presence of electron magnetic ion-cyclotron (EMIC) waves. Using a combination of co-located or conjugate instruments we are able to determine the characteristics and drivers of electron precipitation events, and thereby gain some insight into the loss mechanisms of the outer radiation belt.