Observations of Earth space by self-powered stations in Antarctica

Abstract

Coupling of the solar wind to the Earth magnetosphere/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic poles in the south enables optical observations at a larger range of magnetic latitudes during the winter darkness. The greatest challenge for such ground-based observations is the generation of power and heat for a sizable ground station that can accommodate an optical imaging instrument. Under the sponsorship of the National Science Foundation, we have developed suitable automatic observing platforms, the Automatic Geophysical Observatories (AGOs) for a network of six autonomous stations on the Antarctic plateau. Each station housed a suite of science instruments including a dual wavelength intensified all-sky camera that records the auroral activity, an imaging riometer, fluxgate and search-coil magnetometers, and ELF/VLF and LM/MF/HF receivers. Originally these stations were powered by propane fuelled thermoelectric generators with the fuel delivered to the site each Antarctic summer. A by-product of this power generation was a large amount of useful heat, which was applied to maintain the operating temperature of the electronics in the stations. Although a reasonable degree of reliability was achieved with these stations, the high cost of the fuel air lift and some remaining technical issues necessitated the development of a different type of power unit. In the second phase of the project we have developed a power generation system using renewable energy that can operate automatically in the Antarctic winter. The most reliable power system consists of a type of wind turbine using a simple permanent magnet rotor and a new type of power control system with variable resistor shunts to regulate the power and dissipate the excess energy and at the same time provide heat for a temperature controlled environment for the instrument electronics and data system. We deployed such systems and demonstrated a high degree of reliability in several years of operation in spite of the relative unpredictability of the Antarctic environment. Sample data are shown to demonstrate that the AGOs provide key measurements, which would be impossible without the special technology developed for this type of observing platform.

Quiet time observations of the open‐closed boundary prior to the CIR‐induced storm of 9 August 2008

“…To realize this goal, PENGUIn established the Automated Geophysical Observatories (AGOs). The AGOs can operate unmanned for a full year, powered by sunlight and the wind, before servicing is required [Rosenberg and Doolittle, 1994;Mende et al, 2009]. Instruments housed within each AGO include an imaging riometer, both a searchcoil and a fluxgate magnetometer, an all-sky imager, an ELF/VLF receiver, and a LF/MF/HF receiver.…”

Identifying the evolution of Southern Hemisphere poleward moving auroral forms (PMAFs) in the context of plasma convection and magnetic reconnection

“…In this study we present optical data from the US AGO P1 station (geographic coordinates: 83.86°S, 129.61°E, CGM coordinates: 80.14°S, 16.87°E). This station uses a special dual‐wavelength (427.8 nm and 630.0 nm) all‐sky imager incorporating a two‐channel image intensified charge coupled device camera which captures images in two different wavelengths simultaneously [ Mende et al, ]. The imager uses a single detector in conjunction with a special dual‐wavelength interference filter with two narrow passbands corresponding to each wavelength.…”

Rethinking the polar cap: Eccentric dipole structuring of ULF power at the highest corrected geomagnetic latitudes

“…Each site hosts an assortment of instruments, including a fluxgate magnetometer, which measures the relative variation of the geomagnetic field at a 1 s cadence. To reduce noise, discard extreme outliers (spikes), and account for missing or bad point measurements, the data streams at all stations are downsampled to a 10 s temporal resolution, resulting in a Nyquist period of 20 s. (See reviews by Doolittle and Mende [], Dudeney et al [], Mende et al [], and Melville et al [] for more information on the U.S. AGOs.…”