Archives par mot-clé : Cycle(s)

Climate Cycles, Climate Mechanisms and Determining Accurate Dates

by Dr. Tim Ball, August 31, 2014 in WUWT


Lack of information is a major problem in reconstructing and understanding climate and climate mechanisms. H.H.Lamb gave it as his reason for creating the Climatic Research Unit (CRU).

Notice he is talking about “the facts”, which includes data and other measures. Chief among the other measures are accurate chronologies, which is why he discusses dates and dating methods at some length in Volume 2 of his Climate, Present, Past and Future.

Lamb also divided climate studies into three major areas based on time and method. The secular or instrumental period covers at most 100 years. Few stations are longer and almost all are in Western Europe or eastern North America. The historical period includes the recorded works of humans and covers at most 3000 years. The biologic/geologic record covers the remainder of time. The degree of accuracy diminishes both in measures, such as temperature and precision of dates, as you go back in time. One tragedy of the “hockey stick” rarely discussed was that it misused and demeaned the value of one of the few measures that transcends two or three of these divisions.

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Are we headed for a deep solar minimum?

by Anthony Watts, May 23, 2018 in WUWT


Have you been keeping an eye on Sol lately? One of the top astronomy stories for 2018 may be what’s not happening, and how inactive our host star has become.

The strange tale of Solar Cycle #24 is ending with an expected whimper: as of May 8th, the Earthward face of the Sun had been spotless for 73 out of 128 days thus far for 2018, or more than 57% of the time. This wasn’t entirely unexpected, as the solar minimum between solar cycle #23 and #24 saw 260 spotless days in 2009 – the most recorded in a single year since 1913.

Cycle #24 got off to a late and sputtering start, and though it produced some whopper sunspots reminiscent of the Sol we knew and loved on 20th century cycles past, it was a chronic under-performer overall. Mid-2018 may see the end of cycle #24 and the start of Cycle #25… or will it?

Solar Activity Flat Lines…Cycle 24 Weakest In 200 Years…Link To Recent Northern Hemisphere Ice Rebound?

by F. Bosse and Prof. F. Vahrenholt, April 28, 2018 in NoTricksZone


As the current solar cycle nears an end, it will go down as the weakest in close to 200 years. And as inhabitants of the northern hemisphere dig themselves out of an especially icy and snowy winter and Arctic sea ice rebounds, it may all be in part linked to low solar activity as many scientific studies have long suggested.

Figure 1:  The current solar cycle no. 24 (red) compared to the mean of the previous 23 recorded solar cycles (blue) and the similar solar cycle no. 5 (black)

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The 60-year oscillation revisited

by Javier, April 26, 2018 in WUWT


It is a well-known feature of climate change that since 1850 multiple climate datasets present a ~ 60-year oscillation. I recently wrote about it in the 7th chapter of my Nature Unbound series. This oscillation is present in the Atlantic Multidecadal Oscillation (AMO), Arctic Oscillation (AO), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), Length of Day (LOD), and Global (GST) and Northern Hemisphere (NHT) temperatures, with different lags.

To me this oscillation is not a cycle because prior to 1850 it had a more variable period and it is not well identified in LIA records. Since the origin of this oscillation is unknown, models have a hard time reproducing it and it is all but ignored by the IPCC. It is a big oscillation with an amplitude of ± 0.3 °C in NHT (0.1-0.2°C in GST; figure 2). While the long-term temperature trend is unaffected by it, there is a large effect on the 30-year trends. If this oscillation is considered, most of the climate alarmism vaporizes.

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It appears Solar Cycle 25 has begun – Solar cycle 24 one of the shortest and weakest ever

by A. Watts, April 12, 2018 in WUWT


Evidence of a Cycle 25 sunspot found

In our previous post: Solar activity crashes – the Sun looks like a cueball, 

Our resident solar physicist, Dr. Leif Svalgaard commented and provided a link to something reported by his colleagues, something that likely would not have been possible without the fantastic solar observations of NASA’s Solar Dynamic Observeratory (SDO).

It seems a small sunspot has been observed, that has the opposite polarity of cycle 24 sunspots.

Tools to Spot the Spots

by Willy Eschenbach, March 30, 2018 in WUWT


People have asked about the tools that I use to look for any signature of sunspot-related solar variations in climate datasets. They’ve wondered whether these tools are up to the task. What I use are periodograms and Complete Ensemble Empirical Mode Decomposition (CEEMD). Periodograms show how much strength there is at various cycle lengths (periods) in a given signal. CEEMD decomposes a signal into underlying simpler signals.

Now, a lot of folks seem to think that they can determine whether a climate dataset is related to the sunspot cycle simply by looking at a graph. So, here’s a test of that ability. Below is recent sunspot data, along with four datasets A, B, C, and D. The question is, which of the four datasets (if any) is affected by sunspots?

New paper tries to disentangle global warming from natural ocean variations

by A. Watts, March 15, 2018 in WUWT


This paper deals with the central argument that skeptics bring up about claims of global warming: How do you separate the temperature signal from the base components like natural variation, human land-use influence, micro-site bias, measurement errors and biases, and other factors to get the “true” global warming signal?

The answer is that you can’t, at least not easily.

With the surface temperature record, it’s somewhat easier since  you can observe some of those elements directly and separate them (such as we’ve done in our surfacestations project for land-use microsite biases), but in the ocean, everything is homogenized by the ocean itself. All you can look for is patterns, and try to disentangle based on pattern recognition. That’s what they are trying to do here.

Disentangling Global Warming, Multidecadal Variability, and El Niño in Pacific Temperatures
Authors
Robert C. Wills, Tapio Schneider, John M. Wallace, David S. Battisti, Dennis L. Hartmann

 

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Global SST data confirms cooling is on the way

by P Homewood, January 27, 2018 in NotaLotofPeopleKnowThat


I see that reality is beginning to intrude upon the dangerous global warming team. They say ” it is plausible, if not likely, that the next 10 years of global temperature change will leave an impression of a ‘global warming hiatus’.”
Climate is controlled by natural cycles. Earth is just past the 2003+/- peak of a millennial cycle and the current cooling trend will likely continue until the next Little Ice Age minimum at about 2650.See the Energy and Environment paper at
http://journals.sagepub.com/doi/full/10.1177/0958305X16686488
and an earlier accessible blog version at http://climatesense-norpag.blogspot.com/2017/02/the-coming-cooling-usefully-accurate_17.html

The Antarctic Centennial Oscillation: A Natural Paleoclimate Cycle in the Southern Hemisphere That Influences Global Temperature

by W.J. Davis et al., January 8, 2018 in Climate


We report a previously-unexplored natural temperature cycle recorded in ice cores from Antarctica—the Antarctic Centennial Oscillation (ACO)—that has oscillated for at least the last 226 millennia. Here we document the properties of the ACO and provide an initial assessment of its role in global climate.

See also here

Earth’s Rotation Is Mysteriously Slowing Down: Experts Predict Uptick In 2018 Earthquakes

by Tevor Nace, November 20, 2017 in WhoaScience


Scientists have found strong evidence that 2018 will see a big uptick in the number of large earthquakes globally. Earth’s rotation, as with many things, is cyclical, slowing down by a few milliseconds per day then speeding up again.

You and I will never notice this very slight variation in the rotational speed of Earth. However, we will certainly notice the result, an increase in the number of severe earthquakes.

Geophysicists are able to measure the rotational speed of Earth extremely precisely, calculating slight variations on the order of milliseconds. Now, scientists believe a slowdown of the Earth’s rotation is the link to an observed cyclical increase in earthquakes.

12 New Papers: North Atlantic, Pacific, And Southern Oceans Are Cooling As Glaciers Thicken, Gain Mass

by K Richard, September 11, 2017 in NoTricksZone


Contrary to expectations, climate scientists continue to report that large regions of the Earth have not been warming in recent decades.

According to Dieng et al. (2017), for example, the global oceans underwent a slowdown, a pause, or even a slight cooling trend during 2003 to 2013.  This  undermines expectations from climate models which presume the increase in radiative forcing from human CO2 emissions should substantially increase ocean temperatures.

The authors indicate that the recent trends in ocean temperatures “may just reflect a 60-year natural cycle“, the AMO (Atlantic Multidecadal Oscillation), and not follow radiative forcing trends.

Nature Unbound V – The elusive 1500-year Holocene cycle

by Javier,  September 15, 2017, in Judith Curry Climate Etc.


The existence of a 1500-year climatic cycle during the Holocene, related to the glacial Dansgaard-Oeschger cycle, is a matter of intense debate. However, by introducing precise timing requirements it can be shown that the 1500-year cycle displayed in Northern Hemisphere glacial records is also observed in Holocene records from all over the world.

The cycle is most prominently displayed in oceanic subsurface water temperatures, Arctic atmospheric circulation, wind deposits, Arctic drift ice, and storminess records.