The Operation of an ELF/VLF Radiometer at Arrival Heights, Antarctica

Stanford University, Stanford CA

Investigators

Abstract

This four year continuation of a program to monitor ELF/VLF radio noise (frequencies in the range 5 Hz to 32 kHz) at Arrival Heights, Antarctica, will extend the observational record to more than twenty years, and will allow more precise estimates of noise statistics. The radiometer was first installed at its present location during the austral summer of 1984-5 and has been operated continuously since that time, thus providing a record of ELF/VLF noise in the Antarctic that is unprecedented in its continuity and duration. In parallel with this system, an identical one has been operating on the Stanford University campus for almost the same period of time, thus providing a (northern) mid-latitude comparison data set. Since the predominant sources of ELF/VLF radio noise are thunderstorms occurring in the tropical regions, the Arrival Heights and Stanford systems provide complementary views of the thunderstorm activity occurring in the tropics. The long-term statistics can then provide independent information about global change. The low background in the Arrival Heights record further allows the determination of Schumann resonances. These are quasi-standing electro-magnetic waves that exist in the Earth's 'electromagnetic' cavity (the space between the surface of the Earth and the Ionosphere). Temporal changes in these resonant frequencies can be related to variations in the characteristics of the ionosphere.