Sunspots on a Cloudy Day (APOD 2009 June 4)

[neufer]

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New Solar Cycle Prediction, May 29, 2009

<<An international panel of experts led by NOAA and sponsored by NASA has released a new prediction for the next solar cycle. Solar Cycle 24 will peak, they say, in May 2013 with a below-average number of sunspots.

"If our prediction is correct, Solar Cycle 24 will have a peak sunspot number of 90, the lowest of any cycle since 1928 when Solar Cycle 16 peaked at 78," says panel chairman Doug Biesecker of the NOAA Space Weather Prediction Center.

It is tempting to describe such a cycle as "weak" or "mild," but that could give the wrong impression.

"Even a below-average cycle is capable of producing severe space weather," points out Biesecker. "The great geomagnetic storm of 1859, for instance, occurred during a solar cycle of about the same size we’re predicting for 2013."

The 1859 storm--known as the "Carrington Event" after astronomer Richard Carrington who witnessed the instigating solar flare--electrified transmission cables, set fires in telegraph offices, and produced Northern Lights so bright that people could read newspapers by their red and green glow. A recent report by the National Academy of Sciences found that if a similar storm occurred today, it could cause $1 to 2 trillion in damages to society's high-tech infrastructure and require four to ten years for complete recovery. For comparison, Hurricane Katrina caused "only" $80 to 125 billion in damage.

• 
  Above: This plot of sunspot numbers shows the measured peak of the last solar cycle in blue
  and the predicted peak of the next solar cycle in red.

The latest forecast revises an earlier prediction issued in 2007. At that time, a sharply divided panel believed solar minimum would come in March 2008 followed by either a strong solar maximum in 2011 or a weak solar maximum in 2012. Competing models gave different answers, and researchers were eager for the sun to reveal which was correct.

"It turns out that none of our models were totally correct," says Dean Pesnell of the Goddard Space Flight Center, NASA's lead representative on the panel. "The sun is behaving in an unexpected and very interesting way."

Researchers have known about the solar cycle since the mid-1800s. Graphs of sunspot numbers resemble a roller coaster, going up and down with an approximately 11-year period. At first glance, it looks like a regular pattern, but predicting the peaks and valleys has proven troublesome. Cycles vary in length from about 9 to 14 years. Some peaks are high, others low. The valleys are usually brief, lasting only a couple of years, but sometimes they stretch out much longer. In the 17th century the sun plunged into a 70-year period of spotlessness known as the Maunder Minimum that still baffles scientists.

• 
  Above: Yearly-averaged sunspot numbers from 1610 to 2008. Researchers believe upcoming Solar Cycle 24
  will be similar to the cycle that peaked in 1928, marked by a red arrow.

Right now, the solar cycle is in a valley--the deepest of the past century. In 2008 and 2009, the sun set Space Age records for low sunspot counts, weak solar wind, and low solar irradiance. The sun has gone more than two years without a significant solar flare.

• "In our professional careers, we've never seen anything quite like it," says Pesnell.
  "Solar minimum has lasted far beyond the date we predicted in 2007."

In recent months, however, the sun has begun to show timorous signs of life. Small sunspots and "proto-sunspots" are popping up with increasing frequency. Enormous currents of plasma on the sun’s surface ("zonal flows") are gaining strength and slowly drifting toward the sun’s equator. Radio astronomers have detected a tiny but significant uptick in solar radio emissions. All these things are precursors of an awakening Solar Cycle 24 and form the basis for the panel's new, almost unanimous forecast.

According to the forecast, the sun should remain generally calm for at least another year. From a research point of view, that's good news because solar minimum has proven to be more interesting than anyone imagined. Low solar activity has a profound effect on Earth’s atmosphere, allowing it to cool and contract. Space junk accumulates in Earth orbit because there is less aerodynamic drag. The becalmed solar wind whips up fewer magnetic storms around Earth's poles. Cosmic rays that are normally pushed back by solar wind instead intrude on the near-Earth environment. There are other side-effects, too, that can be studied only so long as the sun remains quiet.

Meanwhile, the sun pays little heed to human committees. There could be more surprises, panelists acknowledge, and more revisions to the forecast. "Go ahead and mark your calendar for May 2013," says Pesnell. "But use a pencil.">>

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[bystander]

• I've got sun spots on a cloudy day
  Only two active regions in the month of May
  
  Well, I guess you say
  What could make Sol act this way?

My apologies to the Temptations.

[Joyce Burks]

I don't understand the photograph on. Why is the right side of the sun shaded? Why isn't photo of sun more or less equally bright all over?

[Joyce Burks]

Intervening clouds?

[apodman]

[My Girl] was written by Smokey Robinson and Ronald White, who were both members of The Miracles. Robinson wrote the lyrics, which were inspired by his wife, Claudette.

In a 2006 NPR interview, Robinson explained that he wrote this with David Ruffin's voice in mind. It was the first Temptations single to feature Ruffin on lead vocals.

... The previous year, Robinson wrote "My Guy" for Motown singer Mary Wells.

Smokey Robinson is America’s greatest living poet.

---

Yes, Joyce, it's a cloud.

[nafpie]

I don't understand the photograph on. Why is the right side of the sun shaded? Why isn't photo of sun more or less equally bright all over?

Remember the title of the image: Sunspots on a Cloudy Day.

I had to wait for 1.5 hours to have the right clouds at the right place...

[orin stepanek]

We know that sunspots have an effect on electronics. They're not supposed to have much affect on the weather though. I noticed that this spring is a little cooler than usual though; not that I mind. I would think that some of those solar flares would carry a lot of energy into space. Seems to me that a one could drift toward Earth and create quite an occurrence in our weather.

Orin
choosing between effect and affect--- hard for me

[BMAONE23]

The theory is, AFAIK, something more opposed to a direct heating affect by increased flaring. From what I understand of the theory:
When Sunspot activity is high, there is more solar pressure being exerted on the Heliopause. This increased pressure acts to block a greater portion of the Cosmic Rays that enter our solar system As Cosmic Rays enter our atmosphere, they react to molecules in the atmosphere creating the seeds for low level clouds.
During times of greater solar activity, more Cosmic Rays are blocked by the solar pressure and fewer lower level clouds develop. This allows more of the available solar IR to reach the surface and things warm up.
During times of lesser solar activity, fewer cosmic rays are blocked and so more, in turn, reach the atmosphere creating the seeds for more lower level clouds. This increased lower level cloudiness blocks the solar IR from reaching the surface and things cool down.
Or so the theory goes.

The debate is on whether the Cosmic ray influence is sufficient to affect the weather to the degree that the climate is also effectively affected.

[astrolabe]

Hello orin,

Affect or Effect? Affect is more of an action type word denoting something like a directed approach toward an end (as if possessing some sort of influence).

Effect lies more in the realm of "result", i.e., cause and "effect".

So: The affect of the Moon has a tidal effect on the ocean.

[Chris Peterson]

We know that sunspots have an effect on electronics. They're not supposed to have much affect on the weather though. I noticed that this spring is a little cooler than usual though; not that I mind. I would think that some of those solar flares would carry a lot of energy into space. Seems to me that a one could drift toward Earth and create quite an occurrence in our weather. :?

Flares themselves don't seem to have any measurable impact on weather. Even if the Earth passes right through a mass ejection, it only has a transient effect as it interacts with our magnetic field- auroras, electrical disturbances, and the like. There is no significant transfer of thermal energy into the atmosphere.

There are several proposed mechanisms by which long term variation in solar activity might impact climate, but other than a direct change in solar irradiance, these ideas remain pretty speculative.

[neufer]

We know that sunspots have an effect on electronics. They're not supposed to have much affect on the weather though. I noticed that this spring is a little cooler than usual though; not that I mind. I would think that some of those solar flares would carry a lot of energy into space. Seems to me that a one could drift toward Earth and create quite an occurrence in our weather.

While there is only a 0.1% increase in solar radiance at solar maximum there is a 10% increase in ultraviolet radiance at solar maximum which results in the summer polar stratopause being about 10º C warmer. This excess in temperature differential between the summer & winter polar stratopauses can result in increased dynamic stratospheric instability when QBO winds are positive (i.e., westerly) as in 1999 & 2002.

The secondary effect of this solar maximum stratospheric instability on the troposphere itself (i.e., on weather) is complicated.

[orin stepanek]

Thanks for the input guys! It's probably a good thing that the solar flares don't cause much problems with the weather. It gets hot enough in the summer and cold enough in the winter as far as I'm concerned. When I was a kid the heat and cold didn't bother me as much as it does now.

Orin

[bystander]

[My Girl] was written by Smokey Robinson and Ronald White, who were both members of The Miracles. Robinson wrote the lyrics, which were inspired by his wife, Claudette.

In a 2006 NPR interview, Robinson explained that he wrote this with David Ruffin's voice in mind. It was the first Temptations single to feature Ruffin on lead vocals.

... The previous year, Robinson wrote "My Guy" for Motown singer Mary Wells.

OK, I should have known that. My apologies to Mr. Smokey Robinson.

Smokey Robinson is America’s greatest living poet.

That's interesting, I've heard Bob Dylan referred to as America's Dylan Thomas (on a PBS tribute to Bob Dylan, I think).

[apodman]

I've heard Bob Dylan referred to as America's Dylan Thomas.

When Mike Doonesbury's Uncle Duke was appointed ambassador to China, his Chinese host explained that Mao Tse Tung was the most revered philosophical character in the Eastern world, "kind of like Bob Dylan in your country".

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Back on the subject of the APOD: In response to a viewer question, a meteorologist once explained that the difference between "partly sunny" and "partly cloudy" is that it's never "partly sunny" at night.

[DavidLeodis]

In the explanation to the APOD it states "The Solar Cycle 24 sunspots recorded here are in active region AR 1019. Previously, only two cycle 24 active regions with sunspots, AR 1018 and AR 1017, were seen in May". However, in the information in the NASA webpage that is brought up through the "cycle 24 active regions" link it gives five figured numbers, not four, for active regions (for example AR 11018). In the information with the image in Stefan Seip's gallery he uses AR 1019. I would be grateful if anyone could tell me what are the correct AR numbers. Thanks. David.

[neufer]

In the explanation to the APOD it states "The Solar Cycle 24 sunspots recorded here are in active region AR 1019. Previously, only two cycle 24 active regions with sunspots, AR 1018 and AR 1017, were seen in May". However, in the information in the NASA webpage that is brought up through the "cycle 24 active regions" link it gives five figured numbers, not four, for active regions (for example AR 11018). In the information with the image in Stefan Seip's gallery he uses AR 1019. I would be grateful if anyone could tell me what are the correct AR numbers. Thanks. David.

<<Active regions are allocated numbers by the US government's National Oceanic and Atmospheric Administration (NOAA) in order of appearance. The present numbering system started on 1972January5. Four‐digit numbers are assigned up to 9999, after which the numbering returns to 0000, as happened on 2002June14; the numbers are prefixed by AR for Active Region. Active regions that exist for more than one solar rotation are given a new number each time they reappear.>>

[DavidLeodis]

Thanks neufer. The AR numbers given in the NASA webpage are therefore wrong. Tut tut NASA.