Tag Archives: Solar Activity

Sunspots Still Elusive

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I last wrote about the lack of sunspots in September 2008. Now, seven months later here in April 2009, even NASA is raising a quizzical eyebrow as it releases a press release discussing what it describes as a very deep solar minimum.

Sunspot Cycle Graph - click for larger imageDespite the press release being dated 1st April, this is no April Fool. Likening solar activity to the stock markets, it describes 2008 as a “bear” year, with no sunspots observed on 266 of the year’s 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008.

Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year’s 90 days (87%).

(Click image for larger version)

Solar physicist Dean Pesnell of the Goddard Space Center said: “We’re experiencing a very deep solar minimum.” The Marshall Space Flight Center’s sunspot expert David Hathaway agrees: “This is the quietest sun we’ve seen in almost a century.”

It’s natural for the sun to undergo a quiet period every 11 years or so. But this quiet?

The sun set some impressive records during 2008:

A 50-year low in solar wind pressure: Measurements by the Ulysses spacecraft reveal a 20% drop in solar wind pressure since the mid-1990s — the lowest point since such measurements began in the 1960s. The solar wind helps keep galactic cosmic rays out of the inner solar system. With the solar wind flagging, more cosmic rays are permitted to enter, resulting in increased health hazards for astronauts. Weaker solar wind also means fewer geomagnetic storms and auroras on Earth.

It might also mean increased cloud cover, causing a cooling of the planet — as I discussed in There Goes The Sun.

Sun Irradiance Graph - click for larger imageA 12-year low in solar “irradiance”: Careful measurements by several NASA spacecraft show that the sun’s brightness has dropped by 0.02% at visible wavelengths and 6% at extreme UV wavelengths since the solar minimum of 1996. The changes so far are not enough to reverse the course of global warming, but there are some other significant side-effects: Earth’s upper atmosphere is heated less by the sun and it is therefore less “puffed up.” Satellites in low Earth orbit experience less atmospheric drag, extending their operational lifetimes. Unfortunately, space junk also remains longer in Earth orbit, increasing hazards to spacecraft and satellites. (Click image for larger version)

A 55-year low in solar radio emissions: After World War II, astronomers began keeping records of the sun’s brightness at radio wavelengths. Records of 10.7 cm flux extend back all the way to the early 1950s. Radio telescopes are now recording the dimmest “radio sun” since 1955. Some researchers believe that the lessening of radio emissions is an indication of weakness in the sun’s global magnetic field. No one is certain, however, because the source of these long-monitored radio emissions is not fully understood.

Whether these lows are “weird”, “extreme” or just an overdue “market correction” following a string of unusually intense solar maxima is currently being hotly debated amongst the experts.

Competing models by dozens of top solar physicists disagree, sometimes sharply, on when this solar minimum will end and how big the next solar maximum will be … The great uncertainty stems from one simple fact: No one fully understands the underlying physics of the sunspot cycle.

Pesnell believes sunspot counts will pick up again soon, “possibly by the end of the year,” to be followed by a solar maximum of below-average intensity in 2012 or 2013. But like other forecasters, he knows he could be wrong.

Read my Climate Change posts in chronological order by using the Climate Change Log.

Still No Sunspots

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The current Solar Cycle — an indicator of the sun’s magnetic activity, which in turn is believed to influence our planet’s climate — is confounding astronomers by resolutely refusing to conform to predictions. There should be increasing numbers of sunspots blemishing the sun’s surface by now, but there are none. What does this trend indicate for our future?

According to Michael Asher, writing in Daily Tech on 1 September 2008, The sun has reached a milestone not seen for nearly 100 years: an entire month has passed without a single visible sunspot being noted.

I wrote about the lack of sunspot activity back in March 2008, in There Goes The Sun — when I quoted from another Michael Asher article highlighting the sudden drop in global average temperature and its possible link to the lack of solar activity since the beginning of Solar Cycle 24, which kicked off at the start of 2008. By now, the sun should be exhibiting an increasingly frequent display of sunspots as it heads to a peak of activity around 2012 — but it isn’t.

Instead, reports Michael, this year has been extraordinarily long and quiet, with the first seven months averaging a sunspot number of only 3. August followed with none at all. The astonishing rapid drop of the past year has defied predictions, and caught nearly all astronomers by surprise. He says that When the sun is active, it’s not uncommon to see sunspot numbers of 100 or more in a single month. Every 11 years, activity slows, and numbers briefly drop to near-zero. Normally sunspots return very quickly, as a new cycle begins. This time, they haven’t.

Sunspot Numbers Graph - from Wikimedia Commons via Daily Tech

Graph from Wikimedia Commons, via Daily Tech

Sunspot data have been collected since 1749. The last time such a quiet entire month was recorded was in June 1913. Three events in the past 1,000 years have occurred where low sunspot activity had a measurable effect on the Earth’s climate. The Dalton, Maunder, and Spörer Minimums have all led to rapid cooling — the Maunder Minimum was what led to the Little Ice Age, when the European and North American continents suffered around 100 years of wan summers and freezing winters.

So is the general consensus changing? Are we moving from a global warming scenario to one of global cooling? Well, the jury’s still out — but it’s not surprising.

On the one hand, our planet has undoubtedly been warming up at an alarming rate recently. The Arctic ice pack has experienced a summer melt this year which almost matches 2007′s record melt. The legendary North-West Passage has been completely ice-free and navigable by commercial vessels for the second year running. This is causing increasing concern about the potential for conflict as countries rush to claim their alleged share of the oil and gas reserves that are coming within reach as the ice recedes. Senior US Coast Guard commander Rear Admiral Gene Brooks, in charge of the Coast Guard’s vast Alaska region, appealed for a diplomatic deal. “The potential is there with undetermined boundaries and great wealth for conflict, or competition. There’s always a risk of conflict,” he told BBC News. He added that this was especially the case “where you do not have established, delineated, agreed-upon borders”.

On the other hand, the same report makes the observation that the melt may also have an effect on the weather far beyond the Arctic region itself, as white reflective ice makes way for darker ocean that absorbs more solar radiation. At America’s northernmost climate research post, run by the National Oceanic and Atmospheric Administration (NOAA), station chief Dan Endres warns of the development of more severe weather systems. ‘As the icecap retreats, and we see changing weather patterns here, it could translate into stronger storms – we’ll see more severity in the storms we have, that’s part of climate change. And these storms, the weather patterns, often start in the Arctic and move south.’

Indeed, that’s the nub of Whitley Strieber and Art Bell‘s argument in their Superstorm theory: Arctic conditions may spiral out of control to such an extent that new, hitherto unobserved weather patterns could emerge that may trigger violent snowstorms across the northern hemisphere, despite — or in fact because of — what’s generally called global warming. Even though average temperatures across the northern hemisphere might be quite high at the time, a vast carpet of snow suddenly deposited across huge areas of Europe, Russia, Canada and North America would reflect enormous amounts of solar energy back into space, slowing that same snow cover’s melt. This would allow further falls of snow to accumulate as more normal weather patterns — influenced by the much colder atmospheric and ground temperatures — resumed, and much of Earth would be in the grip of a period of intense cold that could last for many hundreds of years.

Because Strieber and Bell work on science’s edgy frontier where many researchers fear to tread, their Superstorm theory is dismissed by most, if not all, climatologists. The sun’s current lack of activity, though, has certainly caught scientists’ attention. If it continues, it may well adversely influence our climate enough to neutralise the current warming trend and initiate another “Little Ice Age”. Under these conditions, it’s doubtful whether the atmospheric energy imbalance necessary for Superstorm formation would prevail.

What is certain is that the sun will become more normally active again at some point in the future, and this, in turn, will inject more energy into the complex systems responsible for rising global temperatures and — assuming we haven’t sufficiently curtailed our emissions of carbon dioxide into the atmosphere by then (judging by our current efforts, it’s very doubtful) — the whole warming mechanism will resume, eventually leading to a point where the necessary conditions for Superstorm formation are present once more.

Either way, it seems to this observer that the odds of our future involving some kind of Big Freeze are shortening dramatically.

Read my Climate Change posts in chronological order by using the Climate Change Log.

A Sunny Outlook?

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Once again, the Sun’s influence on the current state of our climate has been called into question, with the link between incoming cosmic rays and global warming being refuted. Meanwhile, Solar Cycle 24 has got off to a grindingly slow start. Where have all the sunspots gone?

Solar WindBack in June 2007, I wrote about some Canadian research that suggested there’s a link to be found between the strength of incoming cosmic rays from deep space and global temperatures. R. Timothy Patterson is professor and director of the Ottawa-Carleton Geoscience Centre, Department of Earth Sciences, Carleton University. His research into mud deposits at the bottom of British Columbia’s fjords found strong correlations between two sets of data: the more incoming cosmic rays, the greater the numbers of scales from dead fish which had perished in temperatures much cooler than they could stand.

CloudsThe cloud-forming capacity of incoming cosmic rays is determined by the amount of protection Earth is given by the Sun’s solar activity: when the Sun is in a highly active phase (indicated by a high number of sunspots), fewer cosmic rays from deep space penetrate our atmosphere because they’re deflected by the Sun’s intense solar wind. Fewer clouds are formed. Less cloud cover means more heat from the Sun is absorbed at the Earth’s surface, and the planet warms up. When the Sun is in a quiet phase (as it is right now), more cosmic rays penetrate the atmosphere, encouraging the formation of more clouds which reflect a greater amount of the Sun’s heat back into space. The planet then cools down. Patterson contends that with the Sun due to undergo a particularly quiet Schwabe Cycle (the formal name for the 11-year Solar Cycles, indicated by sunspot activity) by 2020, the Earth is heading for another period of sustained global cooling, such as was endured during the Middle Ages (the Little Ice Age).

Cosmic Rays v. Global Warming GraphI followed this up in July 2007 with a post detailing more research about the Sun’s influence on Earth — specifically, how data analysis carried out by the UK’s Rutherford-Appleton Laboratory seemed to rule out any cosmic ray influence on the recent trend of rising global temperatures. The laboratory undertook the research in an effort to clarify cosmic ray research published by Henrik Svensmark and Eigil Friis-Christensen of the Danish National Space Center — work included in a controversial TV documentary called The Great Global Warming Swindle and which suggested that global warming has little to do with human activity but is much more influenced by natural phenomena.

The laboratory’s findings reinforced the belief that the warming of the last 20 to 40 years cannot have been caused by solar activity, according to Dr Piers Forster from Leeds University, a leading contributor to the Intergovernmental Panel on Climate Change (IPCC) 2007 assessment of climate science.

Now comes further research, from the University of Lancaster and reported by the BBC, which adds fuel to the fire. The research team used three different ways to search for a correlation and could find no significant link between cosmic rays and cloudiness in the last 20 years.

They looked for periods in time and for places on Earth with documented weak or strong cosmic ray arrivals to see if the cloudiness observed in those locations or at those times was affected. “For example: sometimes the Sun ‘burps’ — it throws out a huge burst of charged particles,” the university’s Terry Sloane explained. “So we looked to see whether cloud cover increased after one of these bursts of rays from the Sun; we saw nothing.” Over the course of one of the Sun’s natural 11-year cycles, there was a weak correlation between cosmic ray intensity and cloud cover — but cosmic ray variability could at the very most explain only a quarter of the changes in cloudiness. And for the following cycle, no correlation was found.

Not surprisingly, Dr Svensmark was unimpressed by the findings, saying that “Terry Sloan has simply failed to understand how cosmic rays work on clouds. He predicts much bigger effects than we would do, as between the equator and the poles, and after solar eruptions; then, because he doesn’t see those big effects, he says our story is wrong, when in fact we have plenty of evidence to support it.”

Sunspot animation - from SpaceWeather.comMeanwhile, Solar Cycle 24, which began when the first high latitude, reversed polarity sunspot appeared on 4th January 2008, has now — at long last — produced its second sunspot (as shown in the animation, from spaceweather.com). This began emerging on 12th April, some three months after the previous Solar Cycle 24 sunspot. It’s not a particularly impressive spot — it hasn’t even been given an official number yet. In the months ahead, says SpaceWeather.com, we can expect more new-cycle spots as solar activity slowly climbs from its current low ebb and ascends toward the next Solar Maximum expected in 2011-12.

The first auroras of the new solar cycle, photographed Jan. 4, 2008, by Calvin Hall of Palmer, Alaska - from NASAI can imagine a collective sigh of relief from the astronomers who first logged the appearance of this elusive second sunspot. The three months between this sunspot and the previous one feels like a long time to me, though as yet I’ve not been able to uncover any comparable detailed data from previous beginnings of Solar Cycles so I can ascertain for myself whether this is actually the case.

Photo: The first auroras of the new solar cycle, photographed Jan. 4, 2008, by Calvin Hall of Palmer, Alaska (NASA)

Maybe, in solar activity terms, three months between the inaugural sunspots of a new cycle is normal — but conversely, perhaps it suggests a slower than usual start to the cycle, which in turn might mean the height of the activity, due around 2012, will be less intense than forecast. And if this were to be followed by a really quiet Solar Cycle 25, as Patterson seems to be suggesting, then maybe the cumulative effect of this decrease in solar activity will have a significant cooling effect here on Earth.

Such a protracted period of decreased solar activity would allow a greater number of cosmic rays to interact with the atmosphere over a longer period of time than is the norm. While the cooling triggered by cosmic ray-generated clouds may not, in isolation, be sufficient to offset global warming caused by ever-increasing volumes of atmospheric greenhouse gases, other factors — such as Gulf Stream cessation and the dramatic disruption of associated weather patterns — may yet come into play to create a combination of climatic conditions that, when acting holistically, could have chilling consequences.

Read my Climate Change posts in chronological order by using the Climate Change Log.