The vertical electric field data were collected using an electric field mill (EFM) developed and deployed under the approval of AAS_974 (Principal Investigator: Gary Burns). The Concordia EFM deployment and data collection was approved by IPEV (France)/PNRA(Italy) via "Electrocite Atmospherique DC 33N".
Associated 20-minute averaged meteorological data are provided for research convenience via permission from Dr Paolo Grigioni and were derived from 1-minute resolution data data collected under IPEV/PNRA "Routine Meteorological Observations at Station Concordia" which is financially supported by PNRA through collaboration with ENEA (Italy).
In January 2009 an electric field mill (EFM) was deployed at Concordia and operated until December 2011. This electric field mill is mounted on an all metal post ~3m above the snow surface. Values are positive for a downward-directed electric field. This EFM is similar to one deployed at Vostok in January 2006. The Concordia EFM 'compression factor' is taken to be equivalent to the similar instrument calibrated at Vostok and was determined by stepping voltages between +5 and -5kV through a wire above the EFM at Vostok. Linkage to the Concordia EFM was determined using a Faraday-shielded box containing parallel plates placed over the rotating dipole to which a range of stepped voltages were applied. A single calibration factor has been applied for the entire (2009-2011) Concordia data set and absolute values (V/m) at ~3m above the snow surface are provided.
Three of the four data sets here-in have been corrected for the solar wind imposed potential (SWIP) above Concordia determined from the Weimer (2001) empirical model (without adjustment for the possible AL auroral index allowance), offset by 20-minutes as the average allowance for the propagation of the interplanetary magnetic field influence from the noon magnetopause to the near-ground-level (~3m) electric field measurements at Concordia. The magnitude of the correction for the SWIP influence and the determination of the appropriate scaling factor are described in the Appendix section of Burns et al. (2017).
The three separate, corrected-for-SWIP, data selections are described in Burns et al. (2017). An initial rejection of the minute-averaged data is made for electric fields with two hour prior to and after exceeding 333 V/m for all data sets. This rejects measurements generally influenced by local falling, wind-blown or lifted snow or ice which result in high electric field values. The extended time intervals are a conservative allowance for the local influences prior to the cut-off electric field value being reached and after lower values are again recorded.
For two of the three separate, corrected-for-SWIP data sets an additional criteria with different levels of severity was used to reject rapid variations below the cut-off threshold based on jumps in the electric field within a five-minute interval. Due to the time constant (~15 minutes) associated with the atmospheric circuit, rapid variations in the electric field are more likely to be associated with local influences. This is confirmed in Burns et al. (2017) by the relative association of the selected data sets with the SWIP-above-Concordia and independently by comparison with simultaneous electric field measurements at Vostok.
Strong variation rejection (svr) data selections reject minute-averaged data within 30 minutes of a jump of 33 V/m (with 5 minutes). Medium variation rejection (mvr) data selections reject minute-averaged data within 10 minutes of a jump of 57 V/m (within 5 minutes). No variation rejection (nvr) data selections made no rejection on the basis of rapid variations (within 5 minutes). At least 16 individual minutes of data (80%) were required for determination of a 20-minute average.
The fourth electric field data set listed herein is the 20-minute average of the nvr data without correction for the local SWIP. Here-in this may be referred to as the 'raw' absolute, 20-minute-average, electric field measurement. Also included with the data are the Weimer (2001) model SWIP (in kV) above Vostok, calculated as described in Burns et al. (2017).
Tests of instrumentation resulted in the earliest 20-minute-averaged electric field measurements at Concordia commencing at 0710UT, 9th January, 2009.
The data provided consists of up to 15 fields.
The first six columns are date-time related fields. The first field is an Excel derived date-time to 6 decimal places of the mid-point of the 20-minute average. The second field is the 'year', followed by the 'month', 'day-of-month' and decimal UT hour (two decimal places) designating the 20-minute averaging interval and then the integer 'day-of-year'.
The seventh column is the Weimer (2001) model (without AL auroral activity adjustment) estimate of the SWIP above Concordia (derived as per explained in Burns et al., 2017).
The eighth column is the 'raw' 20-minute averaged electric field (V/m) at Concordia.
The ninth to eleventh columns list the nvr, mvr and svr Concordia 20-minute electric field averages as described and tested in Burns et al. (2017).
The twelfth to fifteenth columns list the 20-minute averages of the near surface temperature degrees (C), pressure (hP), wind speed (m/s) and wind direction (east of geographic north) derived as described in Burns et al. (2017).
Missing data are presented as blanks.
Suggested acknowledgements for the utilization of these data are:
'The Concordia electric field data were collected by collaboration between AAD (Australia), IPEV (France) and PNRA (Italy). Australian involvement was approved by the Australian Antarctic Advisory Committee (AAS 974). Deployment and data collection at Concordia was approved by IPEV/PNRA via 'Electricite Atmospherique DC 33N'. Concordia meteoroloical data were provided by IPEV/PNRA project 'Routine Meteorological Observations at Station Concordia,' which is financially supported by ENEA (Italy).'
Burns, G.B., A.V. Frank-Kamenetsky, B.A. Tinsley, W.J.R. French, and P. Grigioni, G. Camporeale, and E.A. Bering, 2017: Atmospheric global circuit variations from Vostok and Concordia electric field measurements. J. Atmos. Sci., doi:10.1175/JAS-D-16-0159-1.
Weimer, D.R., 2001: An improved model of ionospheric electric potentials including substorm perturbations and application to the Geospace Environment Modelling November 24, 1996, event. J. Geophys. Res., 106, 407-416.