Solar Topics and Space Weather

Explanation of abbreviations and notations used in the solar banners shared by Paul L. Herrman, N0NBH.

Explanation of how propagation conditions relate to the data values reported in the solar banners

Additional references related to Solar Topics and Space Weather

  Editor’s Note:   Work In Progress.  

Propagation Conditions by Band — provided by RigReference.com
HF Bands — 160 Meters (1.8 MHz) through 6 Meters (50 MHz)
Daylight and Darkness

Solar Information — Refer to the following tables for definitions and explanations of the data elements
Provided by www.hamqsl.com and Paul L. Herrman, N0NBH

Glossary of data abbreviations and other terminology used in the solar banners
Shared by Paul L. Herrman, N0NBH

Term Brief Description Expanded Description
304A 304 Angstroms Range 0 to Unknown.  Updated hourly.  The relative strength of solar radiation at a wavelength of 304 angstroms  This radiation accounts for about half of the F-layer ionization.  
A Planetary A Index Range 0 to 400.  Updated once per day.  This is the daily average for geomagnetic activity taken at three-hour intervals.  Usually evaluated in conjunction with the Planetary K index.  The presence of the word “Planetary” designates the A or K Index as the average of measurements taken at thirteen observatories located around Earth.  A and K both high indicates the geomagnetic field is unstable.  A low and K high indicates an abrupt disturbance of the geomagnetic field which can cause a brief disruption of HF propagation and may cause Aurora.
Aur Aurora (where the data associated with this tag uses words) Word values:  BAND CLOSED (No or Low Activity); HiGH LAT AUR (Activity about 60 degrees); MID LAT AUR (Activity between 60 degrees and 30 degrees);
Aur Aurora (where the data associated with this tag uses numbers) Range 0 to 10++.  Updated hourly.  Indicates strength of the F-Layer ionization in the polar regions.  Higher numbers identify aurora  events occurring at lower latitudes than normal.
Aur Lat Aurora Latitude Range 67.5 to less than 45.0.  Updated hourly.  Indicates the lowest latitude affected by aurora activity.
Bz Bz Component Range +50 to -50.  Updated hourly.  Indicates STRENGTH and DIRECTION of the interplanetary magnetic field.  Positive numbers are in the same direction as Earth’s magnetic field.  Negative numbers are the opposite polarity compared to Earth.
CME Coronal Mass Ejection Predicted Date and Time of an earth-bound CME event. Severity is color coded:  Green is Minor, Yellow is Moderate, Red is Severe.  Updated when NOAA/SWPC provide predictions.
Elc Flx (or EF) Electron Flux x
EME Deg Earth-Moon-Earth Degradation EME path degradation.  Updated every 30 minutes.  Very Poor (greater than 5.5dB); Poor (4dB); Fair (3.1dB); Moderate (2.5dB); Good (1.5dB); Very Good (1dB); Excellent (less than 1dB).   Editor’s Note:  Data Source is www.mmmonvhf.de via www.hamqsl.com
EsEU Sporadic E Europe x
EsNA Sporadic E North America x
GeoMag Fld Geomagnetic Field Reported using the following descriptive words (low to high) INACTIVE, VERY QUIET, QUIET, UNSETTLED, ACTIVE, MINOR STORM, MAJOR STORM, SEVERE STORM, EXTREME STORM.    Updated every three hours.  An indication of Earth’s magnetic field activity obtained from the K index.  
K Planetary K Index Range 0 to 9.  Measured and reported at three-hour intervals.  Generally evaluated in conjunction with the Planetary A index.  See “A” for more information.  The presence of the word “Planetary” designates the A or K Index as the average of measurements taken at thirteen observatories located around Earth.
Ionization Ionization The process by which the energy of UV or X-Ray photon is absorbed by the electron of an atom, removing it completely from the atom and leaving a positively charged ion behind.  
Ionosphere Ionosphere An atmospheric layer in which a small fraction of electrons have been separated from their parent ions by energetic processes. Solar photons, solar protons and auroral particles, with sufficient energy, strip the electrons to produce a weak plasma.
MS Meteor Scatter Color coded range of values (low to high)  Blue, Green, Yellow, Orange, Red.  Updated every 30 minutes.  An indication of meteor scatter activity.
MUF Maximum Usable Frequency x
MUF <loc> Maximum Usable Frequency x
n Normalization x
Pnt Flx (or PF) Proton Flux x
SFI Solar Flux Index Range 62.5 to 300.  Measured three times daily.  This is an indication of the F layer ionization.  The higher the number, the greater the level of ionization.
SN Sunspot Number Range 0 to 250.  Updated daily.  This is a calculated number derived from several inputs.  Sunspot Number (SN) loosely correlates to Solar Flux Index (SFI) 
Sig Noise Lvl Signal Noise Level x
SW Solar Wind Range 0 to 1000.  Updated hourly.  The speed of charged solar particles as they pass Earth.  Measured in kilometers per second.  Numbers above the midpoint probably affect HF communications.
X-Ray Hard X-Rays x

 

Band Openings / Propagation Conditions as indicated through SFI / Solar Flux Index or SN / Sunspot Number

SFI  Solar Flux Index SN Sunspot Number Propagation Conditions
64 – 70 0 – 10 Bands above 40 meters unusable
70 – 90 10 – 35 Poor to Fair conditions all bands up through 20 meters
90 – 120 35 – 70 Fair conditions all bands up through 15 meters
120 – 150 70 – 105 Fair to Good conditions all bands up through 10 meters
150 – 200 105 – 160 Excellent conditions all bands up through 10 meters with some 6 meter openings
200 – 300 160 – 250 Reliable communications all bands up through 6 meters

Radio Blackout Conditions as indicated through X-Ray data values

X-Ray Number Notes / Likelihood Category Propagation Conditions
A1 – A9, B1 – B9 No Flare or Small Flare Normal No, or very minor, impact to HF signals
C1 Moderate Flare Active Low absorption of HF signals
M1 2000 events per solar cycle Minor Occasional loss of radio contact on sunlit side
M5 350 events per solar cycle Moderate Limited HF blackout on sunlit side for tens of minutes
X1 175 events per solar cycle Strong Wide area HF blackout for about an hour on sunlit side
X10 8 events per solar cycle Severe HF blackout on most of the sunlit side for 1 to 2 hours
X20 1 event per solar cycle Extreme Complete HF blackout on entire sunlit side lasting hours

Geomagnetic Storm Conditions using a mix of up to five data sources

K Index K-nT Aurora Solar Wind Bz Description of Propagation Conditions
0-2 0 – 20 LT 5 200-400 0 to +50 Inactive/Quiet, No impact on HF.  Noise S0-S2.  Aurora Latitude 67 – 62 deg.
3-4 20 – 70 6 – 7 200-400 0 to +50 Unsettled/Active.  Minor HF fade at higher latitudes.  Noise S2-S3.   Aurora Latitude 60 – 58 deg.
5 70 – 120 8 400-500 0 to 10 Minor Storm.  HF fade at higher latitudes.  Noise S4-S6.  Aurora Latitude to 56 deg. Likelihood 1700 events per solar cycle.
6 120 – 200 9 500-600 -10 to -20 Major Storm.  HF face at higher latitudes.  Noise S6-S9.  Aurora Latitude to 55 deg. Likelihood 600 events per solar cycle.
7 200 – 330 10 600-700 -20 to -30 Severe Storm.  HF intermittent.  Noise S9-S20.  Aurora Latitude to 50 deg. Likelihood 200 events per solar cycle.
8 330 – 500 10+ 700-800 -30 to -40 Very Major Storm.  HF sporadic.  Noise S20-S30.   Aurora Latitude to 45 deg.  Likelihood 100 events per solar cycle.
9 GT 500 10++ > 800 -40 to -50 Very Major Storm.  HF impossible.  Noise greater than S30.  Aurora Latitude to 40 deg.  Likelihood 4 events per solar cycle.

Solar Radiation Storms as indicated through Proton Flux

Proton Flux Conditions
Up to 1 Normal.  No impacts on HF.
Up to 10 Active.  Very minor impacts on HF in polar regions.
Up to 100 Minor impacts on HF in polar regions.  Likelihood 50 events per solar cycle.
Up to 1,000 Small effects on HF in polar regions.  Likelihood 25 events per solar cycle.
Up to 10,000 Degraded HF propagation in polar regions.  Likelihood 10 events per solar cycle.
Up to 100,000 Partial HF blackout in polar regions.  Likelihood 3 events per solar cycle.
Up to 1,000,000 Complete HF blackout in polar regions.  Likelihood 1 event per solar cycle.
   

Electron Alert as indicated through Electron Flux

Electron Flux Conditions
Up to 1 Normal.
Up to 10 Normal.
Up to 100 Active.  Minor Impacts on HF in polar regions
Up to 1,000 Active.  Degraded HF propagation in polar regions
Greater Than 1,000 Alert.  Partial to complete HF blackout in polar regions
   

Additional Resources:

Noji Ratzlaff, KN0JI provides a nice explanation of the Solar Data Banner at his web page shown below.  A second opinion is a nice thing to have.

https://noji.com/hamradio/pdf-ppt/noji/Noji-Article-Band-Conditions-Banner.pdf