@article{PickKorte2017,
  author    = {Pick, Leonie and Korte, Monika},
  title     = {An annual proxy for the geomagnetic signal of magnetospheric currents on Earth based on observatory data from 1900-2010},
  series = {Geophysical Journal International},
  volume    = {211},
  journal   = {Geophysical Journal International},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {1365-246X},
  doi       = {10.1093/gji/ggx367},
  pages     = {1223 -- 1236},
  year      = {2017},
  abstract  = {We introduce the Annual Magnetospheric Currents index as long-term proxy for the geomagnetic signal of magnetospheric currents on Earth valid within the time span 1900-2010. Similar to the widely used disturbance storm time and 'Ring Current' indices, it is based on geomagnetic observatory data, but provides a realistic absolute level and uncertainty estimates. Crucial aspects to this end are the revision of observatory crustal biases as well as the implementation of a Bayesian inversion accounting for uncertainties in the main field estimate, both required for the index derivation. The observatory choice is based on a minimization of index variance during a reference period spanning 1960-2010. The new index is capable of correcting observatory time series from large-scale external signals in a user-friendly manner. At present the index is only available as annual mean values. An extension to hourly values for the same time span is in progress.},
  language  = {en}
}