Contact: Pete Greene, N2LVI
Copyright © 1999-2003 Victor Amateur Radio Association
Last Updated: 30 October 2003
Geomagnetic
Indices and Conditions | Solar Flare
Classifications | Sunspot/Active Region
Classifications
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| Kp Index |
Ap Index |
GEOMAGNETIC FIELD CONDITIONS |
HF NOISE | AURORA |
| 0 | 0 - 2 | Very Quiet | S1-S2 | None |
| 1 | 3 - 5 | Quiet | S1-S2 | Very Low |
| 2 | 6 - 9 | Quiet | S1-S2 | Very Low |
| 3 | 12 - 18 | Unsettled | S2-S3 | Low |
| 4 | 22 - 32 | Active | S3-S4 | Moderate |
| 5 | 39 - 56 | MINOR Storm | S4-S6 | High |
| 6 | 67 - 94 | MAJOR Storm | S6-S9 | Very High |
| 7 | 111 -154 | SEVERE Storm | S9+ | Very High |
| 8 | 179 -236 | SEVERE Storm | Blackout | Extreme |
| 9 | 300 -400 | EXTREMELY SEVERE | Blackout | Extreme |
| Kp | Planetary K-index, averaged over past 3 hours and tends to be a measure of current conditions |
| Ap | Planetary A-index, 24-hour average and represents overall geomagnetic field conditions for the UTC day |
| HF Noise | Approximate "S-meter" noise level <10 MHz |
| Aurora | Approximate level of auroral activity
|
| Solar Wind | averages 350-450 km/sec and density <10 p/cm^3 >500 km/sec or high density can trigger geomagnetic activity |
| Shock Wave | from a solar flare or Coronal Mass Ejection (CME) arrives at the Earth about 55 hours after the solar event. |
| FLARE CLASS | TYPE OF FLARE | HF RADIO EFFECTS | RESULTING GEOMAGNETIC STORM |
| A | Very small | None | None |
| B | Small | None | None |
| C | Moderate | * Low absorption | * Active to Minor |
| M | Large | * High absorption | * Minor to Major |
| X | Extreme | * Possible blackout | * Major to Severe |
| *Conditions cited if Earth is in trajectory of flare emissions | |||
| Flare class further rated from 1-9, ex. M1,
M2, M3 ... M9 The larger the number, the larger the flare within that class |
|||
| An X7-X9 is considered a "Grand daddy" flare. Only a few have occurred over the past 30 years, causing total disruption to communications, huge aurora's, power grid failures, etc. | |||
| Radio and x-ray emissions from a flare effect the Earth for the duration of the solar event, usually 30 minutes or less. | |||
| Earth is 8 light-minutes from the Sun. | |||
| SUNSPOT CLASS | DESCRIPTION OF THE ACTIVE REGION | POTENTIAL FOR FLARE ACTIVITY |
| Alpha | Unorganized, unipolar magnetic fields | Little threat, but watched for growth |
| Beta | Bipolar magnetic fields between sun spots | C class flares and possible large M class |
| Delta | Strong, compact bipolar fields between spots | High potential for a M or X class major flare Major Flare Alert issued |
From an e-mail posting by Paul
Harden, NA5N, to the "Low Power
Amateur Radio Discussion E-mail List"
06 January 1999 (5:13:15 PM)
© 1999 by Paul Harden, National Radio Astronomy Observatory, Socorro, New
Mexico
"Above information may be freely used in other newsgroups, ham radio
reflectors, non-profit journals, etc., without permission, providing credit is
cited."
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