Antarctic Atmospheric Electricity and Ionospheric Convection

Proposal Summary

Not Under Consideration at Present
None. If you are a program director and wish to have it submitted, call (713) 743-3543 or e-mail <>.
3 years


This proposal requests support for the construction and deployment in Antarctica of instruments that measure the vertical electric field and conduction current in the atmosphere. The questions that will be studied pertain to global climatic change, atmospheric science and ionospheric dynamics. The global electric circuit has two principal generators: the electrical activity of the troposphere and the dynamo interaction of the solar wind with the magnetosphere. In the troposphere, current is driven from the tops of convective electrified clouds into the Earth's ionosphere. This current flows from the ionosphere to the Earth's surface through the partially conducting atmosphere in the non-stormy areas of the Earth. Current in the surface returns to the active areas where cloud-to-ground lightning, and other currents complete the circuit. By monitoring the vertical current density at a fair-weather site, the current flowing in the global electric circuit may be determined. Note that this current is a globally-significant parameter, because it is directly related to global convective activity and therefore to global warming. The Antarctic Plateau is the best location on the Earth to measure the atmospheric electric current density, because it is the highest, driest, flattest area on Earth, the meteorology suppresses convection, and there are no diurnal influences on local conditions. The global electric circuit remains ill-measured experimentally. The theory for its behavior is well established; however, the supporting observations are sparse, largely uncalibrated, and unconvincing without the theoretical underpinning; most data sets have a 1-hour time resolution. Most low-latitude surface observations are dominated by local meteorological influences. The proposed research will directly address these shortcomings by monitoring the global electric circuit at South Pole Station with high time resolution (1 s), high-quality, digitized measurements made for a long period of time (decades) to enable us to understand the behavior of the global electric circuit on all intermediate time scales.The other major objective of this research is to infer the magnetospheric contribution to variations of the air-earth current as a function of time and position. Model studies have shown that ionospheric potential variations with scale sizes on the order of 500 km map down to the Earth's surface. Thus, variations in the air-earth current at the surface are produced by electric fields of magnetospheric origin. Model calculations, multi-point balloon observations and South Pole data have indicated that magnetospheric sources can change the air-earth current by > 20% during periods of geomagnetic quiet and by greater amounts during magnetic storms. Variations of more than 50 V/m in surface field have been observed during magnetospheric substorms. Deployment of a network of atmospheric electric detectors will be begun in order to obtain ``snapshots" of the geomagnetic polar cap potential. The specific objectives of this proposal are:

  1. Analyze the data that have been acquired at South Pole Station during the period January 1991 to October 1993.
  2. Evaluate the possible influences of boundary layer dynamics on the atmospheric electrical measurements.
  3. Deploy two redesigned atmospheric electric stations at either South Pole or Vostok Stations adding passive radioactive probes to measure the electric field profile (surface to 3 m).
  4. In year 2, install detectors at Vostok, South Pole or McMurdo and at one AGO. In year 3, add instruments at two more AGO's.
  5. Correlate atmospheric electric perturbations with perturbations in the geomagnetic field owing to ionospheric currents.