Solar Flux Index (SFI / F10.7)
The F10.7 solar radio flux is a measure of overall solar activity, measured in solar flux units (SFU). Values above 150 indicate an active sun; below 70 is very quiet. This number correlates well with sunspot number and EUV output.
X-ray Flux and Flare Classes
Solar flares are classified by their peak X-ray flux in the 0.1-0.8 nm wavelength band as measured by GOES satellites:
A < 10-7 W/m² (background)
B < 10-6 (quiet)
C < 10-5 (common, minor radio effects)
M < 10-4 (moderate, can cause HF radio blackouts)
X ≥ 10-4 (major, significant radio blackouts, potential radiation storms)
Each class has a 1-9 subdivison (e.g., M3.2). An X-class flare is 10 times stronger than an M-class.
NOAA Space Weather Scales
NOAA categorises space weather impacts on three scales, each ranging from 1 (minor) to 5 (extreme):
R - Radio Blackout: Caused by X-ray flares. R1-R2 = minor HF radio degradation. R3+ = significant blackout affecting aviation and maritime HF communications.
S - Solar Radiation Storm: High-energy proton events. Affects satellite electronics, astronaut safety, polar HF radio. Rare at S3+.
G - Geomagnetic Storm: Caused by CMEs or high-speed solar wind streams. G3+ can produce aurora visible from mid-latitudes including New Zealand. G5 = power grid concerns.
Active Regions
Sunspot groups are assigned NOAA Active Region (AR) numbers. Their magnetic classification indicates flare potential:
Alpha: Simple, single polarity. Low flare risk.
Beta: Two opposite polarities. Moderate flare risk.
Beta-Gamma: Complex mixed polarities. Elevated flare risk.
Beta-Gamma-Delta: Most complex. Highest risk of M and X-class flares.
Solar Disc Views
SDO HMI: Visible light "sunspot" view showing the photosphere. Dark spots indicate regions of intense magnetic activity.
SUVI 195: Extreme ultraviolet at 19.5 nm showing the solar corona at ~1.5 million degrees. Bright areas are active regions; dark regions are coronal holes.
SUVI 304: EUV at 30.4 nm showing the chromosphere/transition region at ~50,000 degrees. Good for seeing filaments and prominences.
LASCO C3: Coronagraph blocking the bright solar disc to reveal the outer corona. Used to detect coronal mass ejections (CMEs) heading towards Earth.
Data Sources
All data sourced from public NOAA Space Weather Prediction Center (SWPC) feeds, GOES satellite X-ray sensors, NASA SDO HMI imagery, and ESA/NASA SOHO LASCO coronagraph. Updated every 60 seconds.