7:15 AM | *An update on Solar Cycle 25* — Arcfield Weather

One of the best ways to determine the influx of cosmic rays on Earth is to measure radiation levels high up in the atmosphere. In fact, measurements using “cosmic ray balloons” in the high atmosphere over California have shown a 15% drop in radiation levels since the early days of solar cycle 25.  Indeed, the most recent measurement on July 23rd was the lowest level recorded during the past 6 years.  These type of measurements are done on a regular basis through the use of balloons and are sponsored by “spaceweather.com” (more information here). This finding of subsiding cosmic radiation is not surprising as the onset of solar cycle 25 – a cycle that is more active than anticipated – has naturally led to the decrease in cosmic radiation reaching the Earth.  Solar maximum for cycle 25 is expected sometime during 2025, so the downward trend in cosmic radiation should continue for a few years to come. 

Impact of solar cycle 25 on the “Great American” total solar eclipse of April 2024

Total solar eclipses provide rare opportunities to gather information for many scientific disciplines including solar dynamics, heliophysics and atmospheric science.  As an example, these events are great for studying the sun’s wispy outer atmosphere known as the corona as the brightness of the sun typically drowns out this outer layer. Indeed, not even a 99 percent eclipse will reveal the sun’s corona.  Temperatures in the corona can reach 1 million °C, making the region much hotter than the solar surface, which is “just” 6,000 °C or so. How the corona gets so hot has puzzled scientists for decades and solar scientists gather useful data during total solar eclipses with the next opportunity here coming in 2024.

The expected solar maximum phase of cycle 25 may actually turn out to be very advantageous for scientists to study the corona during the April 2024 eclipse. Current trends point to the sun having about 125 sunspots when it peaks and this may be not far past the time of the total solar eclipse in April 2024.  A more active sun usually is correlated with a more dynamic corona which is making for a lot of excitement in the solar scientist community regarding the April 2024 total solar eclipse.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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