Long-term solar activity monitoring and solar cycle tracking
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Solar activity follows an approximately 11-year cycle driven by the Sun's magnetic field. During solar maximum, increased sunspot activity leads to more frequent and intense aurora displays. Understanding these patterns helps predict when the northern lights will be most visible in Alaska.
The Sun's magnetic field reverses polarity every 11 years, creating a complete 22-year magnetic cycle. During solar minimum, sunspot numbers drop to near zero, and aurora activity decreases. During solar maximum, the Sun becomes more turbulent, producing more space weather events that enhance aurora visibility.
The quiet phase of the solar cycle, typically lasting 2-3 years. Sunspot numbers are low (often near zero), and the Sun's magnetic field is relatively calm.
The peak of solar activity, typically lasting 2-3 years. Maximum sunspot numbers, frequent flares, and enhanced aurora activity.
Between minimum and maximum, solar activity gradually increases (rising phase) or decreases (declining phase). These transitions last 4-5 years each. During the rising phase, aurora activity steadily improves, while the declining phase still offers good viewing opportunities as the Sun remains active.
Solar activity directly influences aurora visibility and intensity. When the Sun is more active, it releases more charged particles (solar wind) and produces more geomagnetic disturbances that create spectacular northern lights displays.
Continuous stream of charged particles from the Sun. Higher solar activity produces faster, denser solar wind that enhances aurora when it reaches Earth's magnetosphere.
Sudden bursts of radiation from active regions. X-class flares can produce strong geomagnetic storms within 1-2 days, leading to intense aurora displays visible at lower latitudes.
Massive clouds of solar plasma ejected from the Sun. When CMEs reach Earth, they can trigger major geomagnetic storms, producing aurora visible as far south as the continental United States.
During solar maximum, Alaskans can expect more frequent aurora displays throughout the year, with stronger storms producing more vivid colors and dynamic movement. Even during solar minimum, aurora remains visible in Alaska due to the state's high latitude, though displays are typically less frequent and intense. The combination of high solar activity and favorable geomagnetic conditions creates the best viewing opportunities.
The F10.7 cm radio flux measures solar radio emissions at 10.7 cm wavelength (2800 MHz). This is one of the most reliable indicators of solar activity and correlates well with sunspot numbers. Values typically range from 70-90 sfu during solar minimum to 150-300 sfu during solar maximum. Higher flux values generally indicate better aurora potential.
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Chart Interpretation: The blue line shows observed flux values, while the purple dashed line (when available) shows NOAA's 30-day prediction. Rising trends indicate increasing solar activity, which typically improves aurora viewing conditions.
This chart shows the predicted progression of the current solar cycle (Cycle 25, which began in December 2019). The sunspot number is a key metric for tracking solar activity. Higher values indicate more active periods with better aurora viewing opportunities. The cycle typically peaks 4-5 years after minimum.
Understanding the Cycle: Solar cycles are numbered starting from 1755. Cycle 25 is predicted to be similar in strength to Cycle 24 (which was relatively weak). Strong cycles (like Cycle 19 in the 1950s) can produce sunspot numbers exceeding 250, while weak cycles may peak around 100-120.
Explore over 100 years of observed sunspot numbers. Use mouse wheel to zoom, drag to pan, or click Reset to return to full view.
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Data Source: NOAA Space Weather Prediction Center - Observed Solar Cycle Indices. Data includes monthly sunspot numbers from the S.I.D.C. Brussels International Sunspot Number series.
Zoom Controls: Mouse wheel to zoom in/out, click and drag to pan, or use the Reset Zoom button to return to full view.
While solar activity data provides valuable context, remember that:
Solar activity has been systematically observed since the 18th century. Understanding historical cycles helps put current activity in context and provides insights into long-term aurora viewing patterns.
From approximately 1645 to 1715, the Sun entered a period known as the Maunder Minimum, where sunspot activity nearly disappeared for decades. This coincided with the "Little Ice Age" in Europe. While aurora activity was reduced globally, historical records show that aurora were still occasionally visible at high latitudes like Alaska, demonstrating that even during solar minimum, geomagnetic storms can produce aurora displays.
All solar activity data on this page is sourced from the NOAA Space Weather Prediction Center (SWPC), the official U.S. government source for space weather forecasts and data.