From Cardiff University
Sun’s energy influences 1,000 years of natural climate variability in North Atlantic
Changes in the sun’s energy output may have led to marked natural climate change in Europe over the last 1000 years, according to researchers at Cardiff University.
Scientists studied seafloor sediments to determine how the temperature of the North Atlantic and its localised atmospheric circulation had altered. Warm surface waters flowing across the North Atlantic, an extension of the Gulf Stream, and warm westerly winds are responsible for the relatively mild climate of Europe, especially in winter. Slight changes in the transport of heat associated with these systems can led to regional climate variability, and the study findings matched historic accounts of climate change, including the notoriously severe winters of the 16th and 18th centuries which pre-date global industrialisation.
The study found that changes in the Sun’s activity can have a considerable impact on the ocean-atmospheric dynamics in the North Atlantic, with potential effects on regional climate.
Predictions suggest a prolonged period of low sun activity over the next few decades, but any associated natural temperature changes will be much smaller than those created by human carbon dioxide emissions, say researchers.
The study, led by Cardiff University scientists, in collaboration with colleagues at the University of Bern, is published today in the journal Nature Geoscience.
Dr Paola Moffa-Sanchez, lead author from Cardiff University School of Earth and Ocean Sciences, explained: “We used seafloor sediments taken from south of Iceland to study changes in the warm surface ocean current. This was done by analysing the chemical composition of fossilised microorganisms that had once lived in the surface of the ocean. These measurements were then used to reconstruct the seawater temperature and the salinity of this key ocean current over the past 1000 years.”
The results of these analyses revealed large and abrupt temperature and salinity changes in the north-flowing warm current on time-scales of several decades to centuries. Cold ocean conditions were found to match periods of low solar energy output, corresponding to intervals of low sunspot activity observed on the surface of the sun. Using a physics-based climate model, the authors were able to test the response of the ocean to changes in the solar output and found similar results to the data.
“By using the climate model it was also possible to explore how the changes in solar output affected the surface circulation of the Atlantic Ocean,” said Prof Ian Hall, a co-author of the study. “The circulation of the surface of the Atlantic Ocean is typically tightly linked to changes in the wind patterns. Analysis of the atmosphere component in the climate model revealed that during periods of solar minima there was a high-pressure system located west of the British Isles. This feature is often referred to as atmospheric blocking, and it is called this because it blocks the warm westerly winds diverting them and allowing cold Arctic air to flow south bringing harsh winters to Europe, such as those recently experienced in 2010 and 2013.”
Meteorological studies have previously found similar effects of solar variability on the strength and duration of atmospheric winter blockings over the last 50 years, and although the exact nature of this relationship is not yet clear, it is thought to be due to complex processes happening in the upper layers of the atmosphere known as the stratosphere.
Dr Paola Moffa-Sanchez added: “In this study we show that this relationship is also at play on longer time-scales and the large ocean changes, recorded in the microfossils, may have helped sustain this atmospheric pattern. Indeed we propose that this combined ocean-atmospheric response to solar output minima may help explain the notoriously severe winters experienced across Europe between the 16th and 18th centuries, so vividly depicted in many paintings, including those of the famous London Frost Fairs on the River Thames, but also leading to extensive crop failures and famine as corroborated in the record of wheat prices during these periods.”
The study concludes that although the temperature changes expected from future solar activity are much smaller than the warming from human carbon dioxide emissions, regional climate variability associated with the effects of solar output on the ocean and atmosphere should be taken into account when making future climate projections.
Notes for Editors:
Funding for this research has come from the Natural Environment Research Council, UK, the National Science Foundation, Switzerland, the European Commission and NCAR’s Computational and Information Systems Laboratory (CISL). This research forms part of the Climate Change Consortium of Wales (C3W; http://c3wales.org/).
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The paper:
Solar forcing of North Atlantic surface temperature and salinity over the past millennium
Paola Moffa-Sánchez, Andreas Born, Ian R. Hall, David J. R. Thornalley & Stephen Barker
Nature Geoscience (2014) doi:10.1038/ngeo2094
Abstract:
There were several centennial-scale fluctuations in the climate and oceanography of the North Atlantic region over the past 1,000 years, including a period of relative cooling from about AD 1450 to 1850 known as the Little Ice Age1. These variations may be linked to changes in solar irradiance, amplified through feedbacks including the Atlantic meridional overturning circulation2. Changes in the return limb of the Atlantic meridional overturning circulation are reflected in water properties at the base of the mixed layer south of Iceland. Here we reconstruct thermocline temperature and salinity in this region from AD 818 to 1780 using paired δ18O and Mg/Ca ratio measurements of foraminifer shells from a subdecadally resolved marine sediment core. The reconstructed centennial-scale variations in hydrography correlate with variability in total solar irradiance. We find a similar correlation in a simulation of climate over the past 1,000 years. We infer that the hydrographic changes probably reflect variability in the strength of the subpolar gyre associated with changes in atmospheric circulation. Specifically, in the simulation, low solar irradiance promotes the development of frequent and persistent atmospheric blocking events, in which a quasi-stationary high-pressure system in the eastern North Atlantic modifies the flow of the westerly winds. We conclude that this process could have contributed to the consecutive cold winters documented in Europe during the Little Ice Age.
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Glad I could be of service.
(I waited until the post had moved on so as not to start a salvo exchange.)
Some read it from the stand point that it is just another book among many authored by men. They see what they perceive as a flaw and that is enough to validated that belief. Some read it as what it really is and acknowledge that the “flaw” is either in them not understanding what they read or was introduced as it passed through the hands of men before it got to us.
Janice says:
(I’ve had some pretty big boulders heaved at me on WUWT — and, thanks largely to Gunga Din and my ever-supportive hero, Mario, I’m STILL here.)
++++++++++++++
I’m in good company, evidently…
lsvalgaard says:
March 11, 2014 at 7:45 pm
Carla says:
March 11, 2014 at 7:38 pm
Even small variations in Earth’s rotational rate (LOD length of day) will have an effect on atmospheric wind patterns and when they might start establishing new patterns..
You have this backwards. It is the wind patterns and other atmospheric and oceanic variations that have effects on the LOD.
—————————-
Yes, Dr. S., that is true.
But, solar wind dynamic pressures and energetic particle accelerations will also have an effect on atmospheric circulations, as LOD debate continues in the scientific community…… They don’t know what to do with that 5.7 to 6 year variation in LOD that seems to be located on the rise of solar cycle and on the decline of solar cycle. Regular 5 to 6 year delay between max and min of Solar cycle in LOD. LOD goes up then goes down.
From 1880 to 1920 you can see AAM out of phase with solar cycle, then around 1920 looks like they got intimate, as shown in Figure 1 pg. 4
There are two short articles on the link.. the first article was kinda interesting too.
REVISITING A POSSIBLE RELATIONSHIP BETWEEN SOLAR
ACTIVITY AND EARTH ROTATION VARIABILITY
R. ABARCA DEL RIO, D. GAMBIS
http://syrte.obspm.fr/jsr/journees2010/pdf/Aleshkina.pdf
pg. 3
“””A variety of studies have searched to establish a possible relationship between the solar
activity and earth variations (Danjon, 1958-1962; Challinor, 1971; Currie, 1980, Gambis, 1990). We are
revisiting previous studies (Bourget et al, 1992, Abarca del Rio et al, 2003, Marris et al, 2004) concerning
the possible relationship between solar activity variability and length of day (LOD) variations at decadal
time scales. Assuming that changes in AAM for the entire atmosphere are accompanied by equal, but
opposite, changes in the angular momentum of the earth…
pg. 4
Figure 1: Decadal band pass filtered times series, from up to bottom of: Solar Activity (SUN; as repre-
sented by the Sunspots number), the Low Frequency AAM (LF AAM) Annual and Semiannual amplitude
modulation (AN AAM and SA AAM respectively. The decadal cycle of Semi Annual amplitude is inverted
(-SA-A).”””
Carla says:
March 13, 2014 at 3:45 pm
But, solar wind dynamic pressures and energetic particle accelerations will also have an effect on atmospheric circulations, as LOD debate continues in the scientific community
There is no such debate [some wild claims perhaps], but in any case the direction of alleged causality still goes opposite to what you think.
Dear Gunga Din,
Thank you. And thanks for appearing here, way down the thread. You remember some of those boulders, eh? “… we wrestle not with flesh and blood… .” LOVE IS THE ANSWER!
Your sister in Christ,
Janice
************************************************************************
Dear, dear, Mario,
I am so thankful for you! All ALONE in a room, you are in excellent company. The best.
With admiration and gratitude,
Janice
Okay, CARLA #(:)) — it’s your turn — back on topic!
lsvalgaard says:
March 13, 2014 at 3:56 pm
Carla says:
March 13, 2014 at 3:45 pm
But, solar wind dynamic pressures and energetic particle accelerations will also have an effect on atmospheric circulations, as LOD debate continues in the scientific community
There is no such debate [some wild claims perhaps], but in any case the direction of alleged causality still goes opposite to what you think
—————————————
The overall trend in LOD (of the last 40-50 years) has been a slow down. But for that period the solar cycle had been medium/high in activity. Which is consistent with the thinking that higher solar activity, slower rotation rates, due to the high speed solar wind that Earth is faced with in its orbit. We have just experienced our first, really low amplitude solar cycle, so then we might expect a acceleration in Earth’s rotation.
Maybe those four geo-magnetic jerks since ’03’ are telling us something?
Carla says:
March 13, 2014 at 5:42 pm
Which is consistent with the thinking that higher solar activity, slower rotation rates, due to the high speed solar wind that Earth is faced with in its orbit.
That is not how it works, and the solar wind speed has not changed the way you think. The solar wind does not change the Earth’s rotation. Your thinking is wrong. End of story.
I did have the long term trend backwards .. see below..
Characteristics of Perturbations in Recent Length of Day and Polar Motion
Sung-Ho Na†, Younghee Kwak, Jung-Ho Cho, Sung-Moon Yoo, and Sungki Cho
Korea Astronomy and Space Science Institute, Daejeon 305-348, Korea
http://janss.kr/Upload/files/JASS/30-1-33-Na.pdf
pg. 9
4. DISCUSSION AND CONCLUSION
…”””Currently, average LOD is longer by a small amount than its nominal value, and has been decreasing through the last few decades. As noted earlier, positive angular acceleration existed at two time spans; 1981 – 1987 and 1995 – 2003, and recent Earth’s angular velocity has been increased accordingly. Average excessive angular velocity of the Earth since year 2000 is
Δω0 ≃ –0.54±0.47×10 to the-12 (rad/s). Taking this rate as constant yields one leap second for every 4.3 year, which is longer than the average interval of successive leap seconds ever made (1.6 year) or that of last century (1.3 year). Therefore, for the near future, introduction of leap second will not be necessary as often as last century. Earth’s spin angular acceleration is affected by several causes including the change in the Earth’s dynamical form factor J2 and the core motion. Accurate monitoring of J2 has been done by the satellite orbit analysis since 1960s. However, large uncertainty lies in the estimation of angular momentum of core/mantle motion. More realistic simulation of the geomagnetic field generation would greatly improve this situation.”””…
Carla says:
March 13, 2014 at 6:50 pm
I did have the long term trend backwards .. see below..
The Sun has nothing to do with the LOD. I would look at circulation in the liquid core or freezing of its innermost part on to the inner solid core.
Carla says:
March 11, 2014 at 7:38 pm
Even small variations in Earth’s rotational rate (LOD length of day) will have an effect on atmospheric wind patterns and when they might start establishing new patterns..
lsvalgaard says:
March 11, 2014 at 7:45 pm
You have this backwards. It is the wind patterns and other atmospheric and oceanic variations that have effects on the LOD.
Total nonsense Leif.
The Length of day on earth does indeed slow down and speed up. You have claimed that “weather patterns” cause this variation, I disagree. The transfer of energy between weather and earths planetary mass is not transferable to earths orbital parameters, It works from earths orbital parameters (Length Of Day) to weather.
All the planets speed up and slow down during their orbit, and most of them have massive amounts of weather, including Jupiter.
Sparks says:
March 13, 2014 at 9:09 pm
The Length of day on earth does indeed slow down and speed up. You have claimed that “weather patterns” cause this variation, I disagree.
That you disagree does not make you right.
“There is now general agreement that most of the changes in LOD on time scales from weeks to a few years are excited by changes in atmospheric angular momentum” http://en.wikipedia.org/wiki/Fluctuations_in_the_length_of_day
Not a chance Leif,
Weather does not effect a planets orbit.
Sparks says:
March 13, 2014 at 10:16 pm
Weather does not effect a planets orbit.
But does affect the LOD [which is not the orbit]. No need to further elaborate on this. I gave you already a pertinent link.
Sparks — Dr. Svalgaard did not say weather affects a planet’s orbit.
He said (on March 11th at 7:45pm): “…wind patterns and other atmospheric and oceanic variations that have effects on the LOD.”
That is, that such natural phenomena affect Earth’s rotation.
Oh, brother! I was writing my post at the same time as Dr. Svalgaard! Sorry for the apparent (not actual) mimicking.
Not it does not Leif.
I get the joke! (if that’s what you’re getting at?) lol
You are the only one laughing, Sparks.
No, the earths weather does not effect the earths orbit which includes (length of day).
Sparks says:
March 13, 2014 at 10:34 pm
Not it does not Leif.
No need to further elaborate on this. I gave you already a pertinent link.
To clarify Janice, Earths weather has no effect on earths orbit.
Sparks — The earth’s orbit includes the length of day?!
Okay. Sure.
Just like my drive down the freeway “includes” the revolutions per minute of my engine.
To clarify, Sparks, NO ONE SAID THAT IT DOES.
Oh, btw, Sparks you are NOT the only one laughing, now.
#(:))
This is hilarious!
Janice, Lief did, he even provided a “pertinent link”.
I think he’s being funny.