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Alexander555

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Solar cycle
« on: February 11, 2018, 12:05:32 PM »
FishOutofWater
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Re: Global sea ice area and extent data
« Reply #187 on: Today at 04:34:42 PM »
Quote
The effect of a prolonged solar minimum would be modest - tenths of a degree C. It could affect weather patterns, however, as ocean heat would be redistributed in response to the slightly shifted regional radiation balance.

There was a regional "little ice age" that primarily affected Europe. It was mainly caused by northern hemisphere volcanoes. The Maunder minimum in sunspots had an modest impact. Southern hemisphere temperatures dropped slightly.

A deep and long solar minimum would cause a modest drop in forcing that would be significantly less than the increase in forcing caused by increasing levels of GHGs.

I'm writing this from memory based on reading many research papers and discussions.
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I think we can call the levels of GHGs a long term trend. And that solar cycle is a constant short term trend. In general it will change nothing in the long term as long nothing changes at the sun. It just moves up and down along that long term trend. But still that 0,3 degree difference is not a small thing. In some way it's a little amazing to see these record low extents at this point. That could mean something stronger is kicking in. I read we keep building up record amounts of GHGs, we continue to destroy forests. So probably something stronger is kicking in. That makes it interesting to see what extent is going to do in the next 2 or 3 years. If it stays flat or continues to go down it would be bad news for the arctic.

My knowledge is rather fragmented, that puts me easily on the hook for a stupid question. But some people say that stupid questions don't exist. I keep that in mind, even among specialists. That overlapsing from the solar cycle and the ENSO, is there some kind of correlation ?

Gray-Wolf

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Re: Solar cycle
« Reply #1 on: February 11, 2018, 01:17:32 PM »
Anyone involved in highlighting the dangers of AGW will have been battling with folk 'waiting for the next maunder type minimum' as a cure to AGW.

As is noted above the impacts of this are tiny compared to the forces that are both driving and supporting warming.

The albedo flip over the summer Arctic provides far more 'new energy' than the amount of incoming energy we are set to lose? he cleaning of the atmosphere above the Pacific will , likewise, liberate more energy ( at the surface ) than we lose to low solar?

Our problem might come from the conditions low sunspot numbers drive in the atmosphere? Low solar leads to more high pressure around the northern hemisphere and high pressure leads to settled , sunny weather in the continents, this drives drought and so any extended drop in sunspot numbers could lead to extended droughts across inner continents?( not to mention temp hikes?)
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gerontocrat

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Re: Solar cycle
« Reply #2 on: February 11, 2018, 02:24:57 PM »
Alexander,
the latest kerfuffle about the Maunder Minimum has come from a new study by Physicist Dan Lubin, from Scripps Institution of Oceanography at the University of California San Diego, and colleagues. It is just one study, perhaps others disagree.

http://www.techtimes.com/articles/220814/20180211/the-sun-will-be-cooler-by-2050-will-this-end-earths-problem-with-climate-change.htm

The Sun Will Be Cooler By 2050: Will This End Climate Change?

They start by saying that the ultraviolet radiation of the sun will be reduced by an additional 7 percent beyond the lowest point of the 11-year solar cycle during a grand minimum, and ..

Because sunlight will be reduced during this period, global temperatures are expected to drop. The phenomenon appears to offer a natural solution to climate change, which experts fear could lead to a rise in sea level, flooding, and extinction of species.

But read on...

Not A Natural Solution To Climate Change
Lubin and colleagues said that while the solar phenomenon will somehow slow global warming, it will not stop the current trend of human-induced climate change.

They explained that the cooling effect of the grand solar minimum is only a fraction of the warming effect linked to the increasing amount of planet-warming greenhouse gases in the atmosphere.

Elesewhere I saw that the author said, that other climate forcing - e.g. permafrost - methane, could totally overwhelm any possible effect from reduced UV from the Sun.

But then we have our gutter press:-
The Daily Express
The headline:-
‘Mini ice age’ to HIT EARTH as sun to be ‘UNUSUALLY COOL’ by 2050

But even they have to admit it is could only be slowing of the inevitable.

When you see headlines - look beyond them. Meanwhile the insolation season in the Arctic is about to start at the fringes of the ice cap. There are as at 8 Feb 2 million km2 of open ocean at the edge of the Arctic ice cap where in the 1980's there was ice - that is a lot of ocean absorbing most of the sun's radiation instead of reflecting most back into space. CO2 emissions are estimated to have risen 2% in 2017, US emissions are expected to rise in 2018. With world economic growth expected at 3.9% in 2018, world emissions will probably rise. The list is endless.

I confidently expect the earth to be collecting heat (in the oceans) at an accelerating rate for a good few years yet.
"Para a Causa do Povo a Luta Continua!"

Bernard

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Re: Solar cycle
« Reply #3 on: February 11, 2018, 03:29:03 PM »
This kind of "studies" just makes me cry, and the way their results are presented as hard science previsions (The Sun will be cooler by 2050) cry even louder. (For the record, I've been involved in the 80's in the collecting of sunspot numbers data by amateur astronomers.)

We've been observing the Sun for less than 300 years. This is a fraction of the Sun's lifespan, less than 1 in 100,000,000. To compare, it amounts to observing the heartbeats of a man during about  30 seconds. We have no clue whatsoever so far to explain the solar cycles irregularities in both amplitude and length, beyond handwaving ones such as "they are chaotic". Which they certainly are. Extrapolations based on statistics from about 25 cycles can lead to any kind of prediction, with no physical basis whatsoever, just crunching numbers.
See http://sidc.oma.be/silso/yearlyssnplot for the 300 years series, bearing in mind that observations of sunspots before 1750 are partial and difficult to compare with current data.
See also https://arxiv.org/abs/1711.04117 for the kind of models currently used for trying to predict future solar activity, with much more cautious conclusions.

gerontocrat

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Re: Solar cycle
« Reply #4 on: February 11, 2018, 04:28:15 PM »
Good on you, Bernard,

I was hoping someone would come along and flatten this distraction at least in the ASIF- a sunspot in a teacup.

But you won't be able to stop it in the wider world. The Trumps, the Moncktons and the Pruitts of this world will seize on anything going the rounds, e.g. ---

https://principia-scientific.org/top-russian-scientist-fear-a-deep-temperature-drop-not-global-warming/
"Para a Causa do Povo a Luta Continua!"

Alexander555

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Re: Solar cycle
« Reply #5 on: February 11, 2018, 08:17:08 PM »
If i had to chose between the earth cooler by 2050 or the arctic ice free for a short periode by 2025. Than i would chose for the 2th.

Alexander555

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Re: Solar cycle
« Reply #6 on: February 11, 2018, 08:35:05 PM »
This kind of "studies" just makes me cry, and the way their results are presented as hard science previsions (The Sun will be cooler by 2050) cry even louder. (For the record, I've been involved in the 80's in the collecting of sunspot numbers data by amateur astronomers.)

We've been observing the Sun for less than 300 years. This is a fraction of the Sun's lifespan, less than 1 in 100,000,000. To compare, it amounts to observing the heartbeats of a man during about  30 seconds. We have no clue whatsoever so far to explain the solar cycles irregularities in both amplitude and length, beyond handwaving ones such as "they are chaotic". Which they certainly are. Extrapolations based on statistics from about 25 cycles can lead to any kind of prediction, with no physical basis whatsoever, just crunching numbers.
See http://sidc.oma.be/silso/yearlyssnplot for the 300 years series, bearing in mind that observations of sunspots before 1750 are partial and difficult to compare with current data.
See also https://arxiv.org/abs/1711.04117 for the kind of models currently used for trying to predict future solar activity, with much more cautious conclusions.

It's a little strange that they don't say why it would happen. That would have been the most importand part of the study. That's basically the only thing we need to know. And i would think that you need to know exactly how the sun functions, to give that answer.
« Last Edit: February 12, 2018, 02:01:04 PM by Alexander555 »

FishOutofWater

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Re: Solar cycle
« Reply #7 on: February 12, 2018, 03:49:59 AM »
Some regional cooling in and around the Bering sea is expected during a pronounced solar min. Not what we're seeing now. An increase in Bering sea ice is expected.

http://iopscience.iop.org/article/10.1088/1748-9326/11/3/034015/meta

Sleepy

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Re: Solar cycle
« Reply #8 on: February 12, 2018, 12:52:51 PM »
This kind of "studies" just makes me cry, and the way their results are presented as hard science previsions (The Sun will be cooler by 2050) cry even louder. (For the record, I've been involved in the 80's in the collecting of sunspot numbers data by amateur astronomers.)

We've been observing the Sun for less than 300 years. This is a fraction of the Sun's lifespan, less than 1 in 100,000,000. To compare, it amounts to observing the heartbeats of a man during about  30 seconds. We have no clue whatsoever so far to explain the solar cycles irregularities in both amplitude and length, beyond handwaving ones such as "they are chaotic". Which they certainly are. Extrapolations based on statistics from about 25 cycles can lead to any kind of prediction, with no physical basis whatsoever, just crunching numbers.
See http://sidc.oma.be/silso/yearlyssnplot for the 300 years series, bearing in mind that observations of sunspots before 1750 are partial and difficult to compare with current data.
See also https://arxiv.org/abs/1711.04117 for the kind of models currently used for trying to predict future solar activity, with much more cautious conclusions.

It's a little stange that they don't say why it would happen. That would have been the most importand part of the study. That's basically the only thing we need to know. And i would think that you need to know exactly how the sun functions, to give that answer.

Quoting my replies from the other thread, Alexander.

If my interpretation is good. Than it sounds like we are going to lose some more ice in the future.
We will loose more ice, but not because of the sun.
http://spot.colorado.edu/~koppg/TSI/#TSI_data_record
http://solar-center.stanford.edu/sun-on-earth/glob-warm.html

A couple of years back there were discussions about a new little ice age spurred by deniers. But we have effctively disarmed ice ages for many thousands of years to come. Unless something truly drastic happens.
And
I have seen the link now, they are talking about a small difference. That means it can add a little.
First, I never called you a denier, just tried to keep it short because this is OT here.

From the second link I posted and the top link:
Solar Influences on Climate
http://solar-center.stanford.edu/sun-on-earth/Solar%20Influences%20on%20Climate-2009RG000282.pdf
Section 6.4 Climate Change
A value of 0.24 W m−2 solar radiative forcing difference from Maunder Minimum to the present is currently considered to be more appropriate.

Remember, the current cycle (24) is not as low as during the Maunder minimum, not even Dalton, it's similar to those around 1900. As of December 2017 the strength and trend of the southern polar field hints at a cycle 25 with a magnitude slightly stronger than that of cycle 24.

The prediction of cycle 24 (the current) that I'm aware of (please add or correct if some of you out there know more) that has been correct, is made by following the development of the solar polar field strength, throughout a solar sunspot cycle. It can then (if correct) be used to predict the magnitude of the next cycle and the peak of the current cycle. That's why I keep one eye open to see if their prediction of cycle 25 will be correct and somewhat higher than cycle 24. That would then be the opposite to the model posted by Bernard above.

Here's an older presentation by Leif Svalgaard, Stanford University:
http://www.leif.org/research/Comparing-HMI-WSO-Polar-Fields.pdf
We have argued that the ‘poloidal’ field in the years leading up to solar minimum is
a good proxy for the size of the next cycle (SNmax ≈ DM [WSO scale μT]). The
successful prediction of Cycle 24 seems to bear that out, as well as the observed
corroboration from previous cycles. As a measure of the poloidal field we used the
average ‘Dipole Moment’, i.e. the difference, DM, between the fields at the North
pole and the South pole. The 20nHz filtered WSO DM matches well the HMI DM
on the WSO scale (linear correlation at right) using the same 30-day window as
WSO. So, we can extend WSO using HMI into the future as needed. This is good!
Plenty more of his stuff: http://www.leif.org/research/
Edit; the current cycle is similar to cycle 14:
https://en.wikipedia.org/wiki/Solar_cycle_14

Also a recent and highly popular (not... 88 views by now) lecture with him. He's not easy to listen to but it touches many of the problems associated with sun spot observations in the past.



Adding one of my own poor images, from the Venus transit in 2012. I was watching it with my oldest daughter and wasn't focusing on the sunspots, but there are still some, 11 or so, visble.
My own easiest summary? The sun has been very stable for a very long time, but it's still interesting. :)
« Last Edit: February 12, 2018, 01:01:27 PM by Sleepy »
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Gray-Wolf

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Re: Solar cycle
« Reply #9 on: February 12, 2018, 01:10:50 PM »
We already have deniers crying 'foul' because our modern observing notes spots that could not have been viewed over the Maunder minimum?  As such we will not see any 'maunder like minimum' as we will note spots and not a blank sun.
Then we have the major volcanics over the period of the M.M. and the impacts high particulate contents of the atmosphere meant for observation ( and also global temps as we found out recently with the run of small eruptions leading to a slowdown in temp gains?).

Personally i am more concerned will the aiding of Northern blocking over periods of low sunspot numbers and the impacts this may drive on our AGW forced atmosphere?
KOYAANISQATSI

ko.yaa.nis.katsi (from the Hopi language), n. 1. crazy life. 2. life in turmoil. 3. life disintegrating. 4. life out of balance. 5. a state of life that calls for another way of living.
 
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Sleepy

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Re: Solar cycle
« Reply #10 on: February 12, 2018, 01:49:27 PM »
Svalgaard ends his lecture with; We solar physicists are not the most vocal. He earlier believed that bad science will eventually die by itself. But he changed his mind because bad science takes a really long time to die. That's why he added that saying in the first frame: Qui tacet consentire videtur. He who is silent is understood to consent.

Adding a screen shot from that lecture.
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Sleepy

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Re: Solar cycle
« Reply #11 on: February 12, 2018, 02:25:35 PM »
The Maunder minimum and the Little Ice Age: an update from recent reconstructions and climate simulations.
https://www.swsc-journal.org/articles/swsc/pdf/2017/01/swsc170014.pdf

Abstract – The Maunderminimum (MM) was a period of extremely low solar activity from approximately AD 1650 to 1715. In the solar physics literature, the MM is sometimes associated with a period of cooler global temperatures, referred to as the Little Ice Age (LIA), and thus taken as compelling evidence of a large, direct solar influence on climate. In this study, we bring together existing simulation and observational studies, particularly the most recent solar activity and paleoclimate reconstructions, to examine this relation. Using northern hemisphere surface air temperature reconstructions, the LIA can be most readily defined as an approximately 480year period spanning AD 1440–1920, although not all of this period was notably cold. While the MM occurred within the much longer LIA period, the timing of the features are not suggestive of causation and should not, in isolation, be used as evidence of significant solar forcing of climate. Climate model simulations suggest multiple factors, particularly volcanic activity, were crucial for causing the cooler temperatures in the northern hemisphere during the LIA. A reduction in total solar irradiance likely contributed to the LIA at a level comparable to changing land use.

Adding Fig3 at high res.
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Bernard

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Re: Solar cycle
« Reply #12 on: February 13, 2018, 02:32:51 PM »
For those questions, better ask folks being involved for ages in collect and analysis of solar activity data, namely SILSO at Royal Observatory of Brussels.
Their forecast section http://sidc.oma.be/silso/forecasts compares different models, but they cautiously limit them to one year ahead, no more.
Bottom line : The more you know about it, the more cautious you are about predictions.

Bernard

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Re: Solar cycle
« Reply #13 on: February 13, 2018, 02:46:48 PM »
We already have deniers crying 'foul' because our modern observing notes spots that could not have been viewed over the Maunder minimum?  As such we will not see any 'maunder like minimum' as we will note spots and not a blank sun.
The consolidated sunspot number is calibrated based on a network of stations including amateur using small refractors, to avoid as far as possible the bias of "seeing too many spots", and have modern data compared with ancient ones. Note that solar astronomy is peculiar in the sense that the difficulty is not the faintness and apparent small size of objects to observe (like in deep sky astronomy), but the excess of light, and state of the atmosphere (more turbulent in daylight). A spotless sun is spotless in all instruments, from a simple 60mm refractor to dedicated telescopes. And large spots are visible to the filtered naked eye (w/o magnification) or even w/o filter at sunset.
There have been several studies based on historical reports of naked eye sunspots observations, see e.g., http://onlinelibrary.wiley.com/doi/10.1029/2002GL014782/full
« Last Edit: February 13, 2018, 02:57:06 PM by Bernard »

Sleepy

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Re: Solar cycle
« Reply #14 on: February 13, 2018, 03:14:35 PM »
For those questions, better ask folks being involved for ages in collect and analysis of solar activity data, namely SILSO at Royal Observatory of Brussels.
Their forecast section http://sidc.oma.be/silso/forecasts compares different models, but they cautiously limit them to one year ahead, no more.
Bottom line : The more you know about it, the more cautious you are about predictions.
Maybe I don't understand your point but I think there were over a hundred different predictions made for cycle 24 and they used sunspot data from SILSO and polar magnetic field data from Wilcox (Stanford). What is there to be cautious about in trying to make longer predictions?
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Bernard

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Re: Solar cycle
« Reply #15 on: February 13, 2018, 04:19:40 PM »
For those questions, better ask folks being involved for ages in collect and analysis of solar activity data, namely SILSO at Royal Observatory of Brussels.
Their forecast section http://sidc.oma.be/silso/forecasts compares different models, but they cautiously limit them to one year ahead, no more.
Bottom line : The more you know about it, the more cautious you are about predictions.
Maybe I don't understand your point but I think there were over a hundred different predictions made for cycle 24 and they used sunspot data from SILSO and polar magnetic field data from Wilcox (Stanford). What is there to be cautious about in trying to make longer predictions?
Yes indeed, there are a lot of predictions, as said. My point was just that SILSO itself does not venture in long-term predictions, and that such predictions are based more on extrapolation of numbers than on any underlying physical model explaining the variations of the cycle in both strength and length (AFAIK). This is what should be clear in presenting such predictions.