VLF Stations


The high sensitive magnetometric systems "Whistler" are installed in Mikhnevo Geophysical Observatory. They allow to register signals from VLF stations located around the globe. The site presents the results of measuring of the amplitude of signals from the 5 VLF transmitters: JXN, GQD, NAA, DHO, ICV. The "Whistler" characteristics can be found in the Equipment section.

ELF spectrogram


GNSS

The Observatory complex for measurement of the ionosphere parameters includes three GNSS receivers:

  • Javad Sigma
  • Javad Prego
  • Trimble 5700

All receivers (with a sampling rate of 1 second). The raw data is saved in the Rinex 3.02 format. Based on the results of the measurements, the variations of the TEC for each satellite-receiver beam are calculated.

Javad Sigma


Coordinates:
latitude: 54°57´
longitude: 37°46´

  • GPS L1/L2/L5
  • 1 Hz update rate





Javad Prego


Coordinates:
latitude: 54°57´
longitude: 37°46´

  • GPS L1/L2/L5
  • 1 Hz update rate





Trimble 5700


Coordinates:
latitude: 54°57´
longitude: 37°46´

  • GPS L1/L2/L5
  • 1 Hz update rate





LEMI018



K-index



Weather data



Median TEC


To calculate the variations of TEC value on one day we used the data of the Madrigal system capable of managing and serving archival and real-time data from a wide range of ground-based instruments (http://www.openmadrigal.org/). The TEC data is a diurnal file containing the values of TEC for different geographic points with a time step of 5 minutes. These data were averaged by a 15-minute window and distributed along a 180x360 grid in one-degree increments. For each time moment, the median value of TEC (TECmed) was calculated for the 27 previous days. The TEC deviation from the median value (∂TEC) was calculated by the formula:

∂TEC (lat, long, t) = (TEC (lat, long, t) - TECmed (lat, long, t))/ TECmed (lat, long, t),

where lat is latitude, long is longitude and t is UT. Thus the processing of TEC data reproduces the well-known technique from ionosonde data processing. As far as NmF2 gives the significant part of TEC then TEC variations can be studied and analyzed in the same manner as NmF2 temporal dynamics in ionosonde studies.