Abstract:
These data are collected under a collaborative arrangement between the Australian Antarctic Division (Principal Investigator: Gary Burns) and the Russian Antarctic Expeditions (Most-recent contact: Alexandr Frank-Kamenetsky, Institute of Arctic and Antarctic Studies, St Petersburg)
In late December 2005 (call it from 2006) a new electric field mill (EFM)commenced operation at Vostok. This ... electric field mill is mounted on an all metal post ~3m above the snow surface. This EFM is different in operation and deployment from an earlier instrument that operated 1998-2002 and 2004 which was mounted on a 1.5m metal pole at deployment.
Only 'unprocessed' data and a text file of in-field calibration data are included with this download. No selection has been made of 'fair-weather' data.
Filenames of 'unprocessed' data are of the form VOSEF1-2006-002-0000.log VOSEF1 indicates that the data are of Vostok electric field data 2006 indicates the year 002 indicates the day of year 0000 indicates that this is the first file for that day [If there has been continuous data collection, it will be the only file for the day. If the instrument has stopped and been restarted, this number is incremented]
The file is written in ASCII format.
A fileheader is included with each file, of the form: ; EFM Log File ; Date Opened Monday, 2 January 2006 00:00:00 ; ; 1 - DOY ; 2 - TimeStamp ; 3 - RPM ; 4 - Field ; 5 - Cal State ; 6 - Rotor Temperature ; DOY, timestamp, RPM, Field, Cal, Rotor Temp 002,2006-01-02 00:00:00,1618,3958654,0,5.68
'DOY' is Day-Of-Year 'timestamp' is date and time, in Universal time. 'RPM' is 'rotations per minute', the speed of rotation of the dipole. For most of the year this value is not correctly recorded. 'Field' is just the raw digital value of the measurement 'Cal' there are two internal calibrations possible. A cal state of '1' indicates an internal 'zero level' check and a cal state of '2' indicates a fixed voltage offset (never fully calibrated). A '0' cal state indicates an atmospheric measurement was being made. From about 16th January 2006 on, no internal calibration have been activated. The cal state is always '0' indicating an atmospheric measurement is being made. 'Rotor Temperature' is the temperature of the electronics in degrees C.
Up until 16th January 2006 various tests and comparisons were being made with the instrument and while the 'unprocessed' data fro this early interval is provided, regular measurements commenced at this date.
The 'Field' raw values are relative vertical geoelectric field measurements collected every 10 seconds. They are positive for a field directed downward.
Each month the EFM is calibrated by placing a Faraday Box over the instrument. A separate calibration ASCII text file for each year [e.g. EFM_Cal_2006.txt] indicates the calibration results. These have not been applied to the data supplied. Care needs to be taken as difficulties with the calibration procedure (for example ice in one side of the calibration cables) have been known to occur. These issues are discussed, when noticed, in the calibration text file. Applying the calibration results to the raw data does not yield absolute values. They are determined relative to the 'calibration box', but as the compression associated with the instrumentation is unknown, data can only be regarded as relative not absolute measurements. As a rough estimate, dividing the 'field' value by 10,000 yields an value approximately equal to the 'volts per metre', positive downward, relative to the calibration box. Note: the instrument compression associated with the 'installed-in-2006' EFM is significantly different to the 1998-2004 Vostok EFM, principally but not exclusively due to the different heights of the mill.
For the 'unprocessed' data supplied no selection for 'fair-weather' has been made. A method of selecting 'fair-weather' data for the 1998-2002 data is described in: Burns, G.B., Frank-Kamenetsky, A.V., Troshichev, O.A., Bering, E.A., Reddell, B.D. (2005) Interannual consistency of bi-monthly differences in diurnal variations of the ground-level, vertical electric field. Journal of Geophysical Research 110, D10106. doi:10.1029/2004JD005469. This method cannot be directly applied to the post-2006 data due to the different 'instrument compression'
Gary Burns is working on a 'fair weather' selection of the Vostok post-2006 data, and a comparison with coincident vertical electric field measurements at Concordia.
The ASAC_974 project formally concluded in June 2011, but the Russians (contact: Alexandr Frank-Kamenetsky, Institute of Arctic and Antarctic Studies, St Petersburg) have continued data collection at Vostok after this time, under an agreement to utilise the Australian developed equipment.
Taken from the 2008-2009 Progress Report: Public summary of the season progress: Two papers showing a sun-weather association (ground pressure and clouds with solar wind) and linking the process to the atmospheric circuit have been published. These support a process via which solar variability influences weather via the atmospheric circuit.
Vertical electric field data were collected at Vostok over 2008.
An electric field mill was deployed at Dome C (Concordia) to help distinguish global and local influences on the atmospheric circuit.
Taken from the 2009-2010 Progress Report: Public summary of the season progress: Global warming leads to enhanced atmospheric convection. Associated electrical activity (thunderstorms and electrified clouds) dominantly drives a globally-uniform atmospheric circuit linking the ionosphere to the surface. Four papers investigating atmospheric convection linkages to the ionosphere were published.
Electric field data were collected at Vostok and Concordia on the Antarctic Plateau to measure the atmospheric circuit. The dominance of a global signal (atmospheric convection) in these measurements and an improved understanding of local contributions (solar wind and local meteorology) were obtained.
A World Wide Lightning Location Network receiver was re-established at Davis. This contributes to a global lightning detection network [http://webflash.ess.washington.edu/]
See also the metadata records with the IDs - ASAC_974_1 and ASAC_974_Concordia.
Latitude Resolution:
2.5 degrees
Longitude Resolution:
2.5 degrees
Horizontal Resolution Range:
100 km - < 250 km or approximately 1 degree - < 2.5 degrees
ERA-40 Project Report Series No. 19 Kållberg, P., P. Berrisford, B. Hoskins, A. Simmmons, S. Uppala, S. Lamy-Thépaut and R. Hine: ERA-40 Atlas. [Note: Large PDF file: 68.3 MB; Revised version posted 19.01.2006] June 2005
Uppala, S.M., Kållberg, P.W., Simmons, A.J., Andrae, U., ... da Costa Bechtold, V., Fiorino, M., Gibson, J.K., Haseler, J., Hernandez, A., Kelly, G.A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R.P., Andersson, E., Arpe, K., Balmaseda, M.A., Beljaars, A.C.M., van de Berg, L., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Hólm, E., Hoskins, B.J., Isaksen, L., Janssen, P.A.E.M., Jenne, R., McNally, A.P., Mahfouf, J.-F., Morcrette, J.-J., Rayner, N.A., Saunders, R.W., Simon, P., Sterl, A., Trenberth, K.E., Untch, A., Vasiljevic, D., Viterbo, P., and Woollen, J. 2005: The ERA-40 re-analysis. Quart. J. R. Meteorol. Soc., 131, 2961-3012.doi:10.1256/qj.04.176
