C index

{
  "id": "MLC-T-MET-004103",
  "term": "C index",
  "field": "Meteorology and atmospheric science",
  "definition": "A subjectively assigned daily index of geomagnetic activity, in which observers at magnetic observatories rate each day from its magnetogram as 0 for quiet, 1 for moderately disturbed or 2 for highly disturbed. The values from participating observatories are averaged to give one international figure for the day. It is also called the C figure or magnetic character figure, and it is much coarser than the K index, which is recorded in three-hour intervals.",
  "see_also": [
    "Kp"
  ],
  "url": "https://mlchart.com/terminology/meteorology/c-index/"
}