EU project
Equivalent current processing in the FP7 ECLAT project

The European Cluster Assimilation Technology (ECLAT) project funded by the EU FP7 programme provides a selection of useful supporting data sets to the Cluster Active Archive. The Finnish Meteorological Institute has conducted in ECLAT the work packages, in which ionospheric equivalent current vectors are computed in the Fennoscandia region where the MIRACLE network of magnetometers (IMAGE) are operated. The currents have been calculated with the method of Spherical Elementary Current Systems [Amm and Viljanen, 1999; Pulkkinen et al., 2003]. The analysed data period covers years 2001-2010. A novel method by van de Kamp (2013) has been used for baseline subtraction in the analysis.

Primary source for the ECLAT equivalent current data will be the Cluster Active Archive, from where the data are available either as 2D (latitude-longitude) maps or as 1D data (latitude versus time) with 10 s resolution. The data set includes also quality flags which warn the user about data gaps and potential uncertainties in baseline determination. Only for testing purposes (e.g. for testing the impact of choosing different baseline periods) FMI provides on-line tools for plotting the ECLAT equivalent current data in the following links:

  • QL tool for 1D equivalent current plots
  • QL tool for 2D equivalent current plots

  • Amm, O., and A. Viljanen (1999): Ionospheric disturbance magnetic field continuation from the ground to the ionosphere using spherical elementary current systems, Earth Planets Space, 51, 431-440.
  • Pulkkinen, A., O. Amm, A. Viljanen and BEAR Working Group (2003): Ionospheric equivalent current distributions determined with the method of spherical elementary current systems, J. Geophys. Res., 108(A2), 1053, doi: 10.1029/2001JA005085.
  • Van de Kamp, M., Harmonic quiet-day curves as magnetometer baselines for ionospheric current analyses, Geosci. Instrum. Method. Data Syst., 2, 289-304, 2013.