sunspot

Solar Cycle 25 is Here!

Posted on by VA3DBJ

Analysis determines we are in Solar Cycle 25

The solar minimum between Solar Cycle 24 and 25 – the period when the sun is least active – happened in December 2019, when the 13-month smoothed sunspot number fell to 1.8, according to the Solar Cycle 25 Prediction Panel, co-chaired by NOAA and NASA. We are now in Solar Cycle 25 with peak sunspot activity expected in 2025, the panel said.

Solar Cycle 24 was average in length, at 11 years, and had the 4th-smallest intensity since regular record keeping began with Solar Cycle 1 in 1755. It was also the weakest cycle in 100 years. Solar maximum occurred in April 2014 with sunspots peaking at 114 for the solar cycle, well below average, which is 179.

Solar Cycle 24’s progression was unusual. The Sun’s Northern Hemisphere led the sunspot cycle, peaking over two years ahead of the Southern Hemisphere sunspot peak. This resulted in solar maximum having fewer sunspots than if the two hemispheres were in phase.

Solar Cycle 25

For the past eight months, activity on the sun has steadily increased, indicating we transitioned to Solar Cycle 25. Solar Cycle 25 is forecast to be a fairly weak cycle, the same strength as cycle 24. Solar maximum is expected in July 2025, with a peak of 115 sunspots.

“How quickly solar activity rises is an indicator on how strong the solar cycle will be,” said Doug Biesecker, Ph.D., panel co-chair and a solar physicist at NOAA’s Space Weather Prediction Center. “Although we’ve seen a steady increase in sunspot activity this year, it is slow.”

The panel has high confidence that Solar Cycle 25 will break the trend of weakening solar activity seen over the past four cycles. “We predict the decline in solar cycle amplitude, seen from cycles 21 through 24, has come to an end,” said Lisa Upton, Ph.D., panel co-chair and solar physicist with Space Systems Research Corp. “There is no indication we are approaching a Maunder-type minimum in solar activity.”

“While we are not predicting a particularly active Solar Cycle 25, violent eruptions from the Sun can occur at any time,” Biesecker added.

Solar cycle prediction gives a rough idea of the frequency of space weather storms of all types, from radio blackouts to geomagnetic storms and solar radiation storms. It is used by many industries to gauge the potential impact of space weather in the coming years.

New satellites will provide enhanced observations of the Sun

In 2024, before the peak of sunspot activity in Solar Cycle 25, NOAA is slated to launch a new spacecraft dedicated to operational space weather forecasting. NOAA’s Space Weather Follow-On L-1 observatory will be equipped with instruments that sample the solar wind, provide imagery of coronal mass ejections, and monitor other extreme activity from the Sun in finer detail than before. NOAA’s next Geostationary Operational Environmental Satellite (GOES-U) is also scheduled to launch in 2024. GOES-U will carry three solar monitoring instruments, including the first compact coronagraph, which will help detect coronal mass ejections. Enhanced observations of the Sun from these satellites will help improve space weather forecasting.

The Solar Cycle Prediction Panel forecasts the number of sunspots expected for solar maximum, along with the timing of the peak and minimum solar activity levels for the cycle. It is comprised of scientists representing NOAA, NASA, the International Space Environment Services, and other U.S. and international scientists.

For the latest space weather forecast, visit NOAA’s Space Weather Prediction Center, the nation’s authority for space weather alerts, watches, warnings, and advisories at https://www.spaceweather.gov/.

Experts Predict a Long, Deep Solar Minimum

Posted on by VA3DBJ

Dr.Tony Phillips on April 10, 2019

If you like solar minimum, good news: It could last for years. That was one of the predictions issued last week by an international panel of experts who gathered at NOAA’s annual Space Weather Workshop to forecast the next solar cycle. If the panel is correct, already-low sunspot counts will reach a nadir sometime between July 2019 and Sept 2020, followed by a slow recovery toward a new Solar Maximum in 2023-2026.

“We expect Solar Cycle 25 will be very similar to Cycle 24: another fairly weak maximum, preceded by a long, deep minimum,” says panel co-chair Lisa Upton, a solar physicist with Space Systems Research Corp.

The solar cycle is like a pendulum, swinging back and forth between periods of high and low sunspot number every 11 years or so. Researchers have been tracking the cycle since it was discovered in the 19th century. Not all cycles are alike. Some are intense, with lots of sunspots and explosive solar flares; the Space Age began with a big booming solar maximum. Others are weak, such as the most recent, Solar Cycle 24, which peaked in 2012-2014 with relatively little action.

Researchers are still learning to predict the ebb and flow of solar activity. Forecasting techniques range from physical models of the sun’s inner magnetic dynamo to statistical methods akin to those used by stock market analysts.

“We assessed ~61 predictions in the following categories: Climatology, Dynamo, Machine Learning/Neural Networks, Precursor Methods, Spectral/Statistical Methods, Surface Flux Transport, and Other,” says Upton. “The majority agreed that Solar Cycle 25 would be very similar to Solar Cycle 24.”

“Here,” she says, “is a figure showing the last minimum and where we are with the current minimum.”

“As you can see – we haven’t quite reached the lowest levels of the last cycle – where we experienced several consecutive months with no sunspots. However, the panel expects that we should reach those levels.”

In recent years, the Internet has buzzed with the idea that a super-deep solar minimum such as the 70-year Maunder Minimum of the 17th century might cool the Earth, saving us from climate change. That’s not what the panel is saying, however.

“There is no indication that we are currently approaching a Maunder-type minimum in solar activity,” says Upton. Solar minimum will be deep, but not that deep.

The panel predicts a “fairly weak” Solar Cycle 25. What does that mean? Saying that a solar cycle is “weak” is a bit like saying hurricane season will be “weak.” In other words, there may be fewer storms, but when a storm comes, you’d better batten down the hatches. “Weak” Solar Cycle 24 produced a number of intense X-class solar flares, strong geomagnetic storms, and even a Ground Level Event (GLE) when solar energetic particles reached Earth’s surface. An equally “weak” Solar Cycle 25 could do the same 3 or 4 years hence.

Meanwhile, we have solar minimum. This is a widely misunderstood phase of the solar cycle. Many people think it brings a period of dull quiet. In fact, space weather changes in interesting ways. For instance, as the sun’s magnetic field weakens, holes open in the sun’s atmosphere. Emerging streams of solar wind buffet Earth’s magnetic field, sustaining auroras even without solar flares and sunspots. Some observers believe that Solar Minimum auroras have a distinctive palette, pinker than during other phases of the solar cycle.

The sun’s weakening magnetic field also allows cosmic rays to enter the solar system. Energetic particles from deep space penetrate Earth’s atmosphere with a myriad of possible effects ranging from changes in upper atmospheric electricity to extra doses of radiation for people on airplanes.

Finally, the sun dims, especially at extreme ultraviolet wavelengths. This, in turn, causes the upper atmosphere to cool and contract. Aerodynamic drag that would normally cause satellites to decay is reduced; space junk accumulates. This effect makes solar minimum a terrible time to blow up satellites–although people do it anyway.

The Solar Cycle Prediction Panel is comprised of scientists representing NOAA, NASA, the International Space Environment Services, and other U.S. and international scientists. Their April 5th prediction was preliminary, and they plan to issue a refined forecast by the end of 2019. Stay tuned.