---------------------------------------------------------------------------- | NOAA Space Weather Scale for Geomagnetic Storms | ---------------------------------------------------------------------------- | Category | | | | -------------------| | Physical | Avg. Frequency | |Scale | Descriptor| Effect | Measure |(cycle=11 years)| |------|-----------|---------------------------|----------|----------------| | | | number of | | | Planetary| storm events | | Geomagnetic Storms | K Index | (number of | | | (Kp) | storm days) | |------|-----------|---------------------------|----------|----------------| | G5 | Extreme | HF (high frequency) radio | Kp = 9 | 4 per cycle | | | | propagation may be | | (4 days/cycle) | | | | impossible in many areas | | | | | | for one to two days, | | | | | | satellite navigation may | | | | | | be degraded for days. | | | |------|-----------|---------------------------|----------|----------------| | G4 | Severe | HF radio propagation | Kp = 8 | 100 per cycle | | | | sporadic, satellite | | (60 days/cycle)| | | | navigation degraded for | | | | | | hours. | | | |------|-----------|---------------------------|----------|----------------| | G3 | Strong | HF radio may be inter- | Kp = 7 | 200 per cycle | | | | mittent, intermittent | |(130 days/cycle)| | | | satellite navigation. | | | |------|-----------|---------------------------|----------|----------------| | G2 | Moderate | HF radio propagation can | Kp = 6 | 600 per cycle | | | | fade at higher latitudes. | |(360 days/cycle)| | | | latitudes. | | | |------|-----------|---------------------------|----------|----------------| | G1 | Minor | Minor impact on HF radio | Kp = 5 | 1700 per cycle | | | | propagation at higher | |(900 days/cycle)| | | | latitudes. | | | |------|-----------|---------------------------|----------|----------------| ---------------------------------------------------------------------------- | NOAA Space Weather Scale for Solar Radiation Storms | ---------------------------------------------------------------------------- | Category | | | | -------------------| | Physical | Avg. Frequency | |Scale | Descriptor| Effect | Measure |(cycle=11 years)| |------|-----------|---------------------------|----------|----------------| | | | number of | | |Flux level| storm events | | Solar Radiation Storms | >= 10 MeV| (number of | | | (ions)* | storm days) | |------|-----------|---------------------------|----------|----------------| | S5 | Extreme | Complete blackout of HF | 10^5 | Fewer than | | | | communications possible | | 1 per cycle | | | | through the polar regions,| | | | | | and position errors make | | | | | | satellite navigation | | | | | | extremely difficult. | | | |------|-----------|---------------------------|----------|----------------| | S4 | Severe | Blackout of HF communi- | 10^4 | 3 per cycle | | | | cations through the polar | | | | | | regions and increased | | | | | | navigation errors over | | | | | | several days are likely. | | | |------|-----------|---------------------------|----------|----------------| | S3 | Strong | Degraded HF radio propa- | 10^3 | 10 per cycle | | | | gation through the polar | | | | | | regions and navigation | | | | | | position errors likely. | | | |------|-----------|---------------------------|----------|----------------| | S2 | Moderate | Small effects on HF radio | 10^2 | 25 per cycle | | | | through the polar regions | | | | | | and navigation at polar | | | | | | caps possibly affected. | | | |------|-----------|---------------------------|----------|----------------| | S1 | Minor | Minor impact on HF radio | 10^1 | 50 per cycle | | | | in the polar regions. | | | |------|-----------|---------------------------|----------|----------------| *Flux levels are 5 minute averages. Flux in particles x s-1 x ster-1 x cm-2. Based on this measure, but other physical measures are also considered. ---------------------------------------------------------------------------- | NOAA Space Weather Scale for Radio Blackouts | ---------------------------------------------------------------------------- | Category | | | | -------------------| | Physical | Avg. Frequency | |Scale | Descriptor| Effect | Measure |(cycle=11 years)| |------|-----------|---------------------------|----------|----------------| | | | number of | | |GEOS X-ray| events | | Radio Blackouts | by class | (number of | | | and flux*| storm days) | |------|-----------|---------------------------|----------|----------------| | R5 | Extreme | Complete HF radio blackout| X20 | Fewer than | | | | on the entire sunlit side | (2x10^-3)| 1 per cycle | | | | of the Earth lasting for | | | | | | several hours. Increased | | | | | | satellite navigation | | | | | | position errors on the | | | | | | sunlit side of the Earth. | | | |------|-----------|---------------------------|----------|----------------| | R4 | Severe | HF radio communication | X10 | 8 per cycle | | | | blackout on most of the | (10^-3) | (8 days/cycle) | | | | sunlit side of Earth for | | | | | | one to two hours. Minor | | | | | | disruptions of satellite | | | | | | navigation possible on | | | | | | sunlit side of the Earth. | | | |------|-----------|---------------------------|----------|----------------| | R3 | Strong | Wide area blackout of HF | X1 | 175 per cycle | | | | radio communication, loss | (10^-4) |(140 days/cycle)| | | | of radio contact for about| | | | | | an hour on sunlit side of | | | | | | the Earth. | | | |------|-----------|---------------------------|----------|----------------| | R2 | Moderate | Limited blackout of HF | M5 | 350 per cycle | | | | radio communication on | (5x10^-5)|(300 days/cycle)| | | | sunlit side, loss of radio| | | | | | contact for tens of | | | | | | minutes. | | | |------|-----------|---------------------------|----------|----------------| | R1 | Minor | Weak or minor degradation | M1 | 2000 per cycle | | | | of HF radio communication | (10^-5) |(950 days/cycle)| | | | on sunlit side, occasional| | | | | | loss of radio contact. | | | |------|-----------|---------------------------|----------|----------------| *Flux, measured in the 0.1-0.8 nm range, in W x m-2. Based on this measure, but other physical measures are also considered.