by Tony Brown
This article examines the continued cooling of CET this century
- Looks at a similar scenario of regional cooling in America
- Examines CET related urbanisation issues, and the current Met office allowances for this
- Notes the centuries long general warming of our climate.
- Notes considerable English seasonal variability over the centuries
- Examines the key component parts of the weather that affect the British Isles
- Queries whether wind direction, strength and longevity are major factors in shaping our climate over the centuries.
Note: Weather comprises the day to day events that we all experience. Climate is officially the trend of the weather (often temperature and rainfall) taken over a continuous thirty year period. The two terms have sometimes been used in an interchangeable manner here, when a period of more than a year is being examined.
Some two years ago I wrote this article The Rise and Fall of Central England Temperature. This article commented on the interesting-but not climatically valid-observation that no one born in England this century has known warming; in fact there had been a slight decline in temperatures, albeit still maintained at a historically high level.
This data – using Central England Temperature (CET) which is maintained by the Met Office – has now been updated to the end of 2017 as shown in Figure 1. It shows this decline continuing, although recent warm seasons have slightly reduced the downwards trend
Figure 1
To put this into a much broader context, here is the seasonal data from the start of the CET record in 1660.
Figure 2
Figure 2a linked here [2a ], shows the seasonal temperatures in much greater detail.
The recent cooling was interesting, as it appeared that CET fitted into the pattern of an earlier article I co-authored with Verity Jones In Search of Cooling Trends.
This graphic shows some of the stations identified as cooling over the statistically meaningful period of at least 30 years
Figure 3
The take home message was that whilst undoubtedly most stations around the world had warmed in recent decades, it could be observed that there were large warming AND cooling trends in many places. With regards to cooling, some one third of stations worldwide showed a trend that was downwards, rather than upwards. This was confirmed by Richard Muller of the BEST project several years ago in a personal email, but it must be said there are many caveats to this observation, especially as regards the length, amount and consistency of this cooling.
In 2016 Professor Muller wrote an article in which he observed the areas of sustained cooling in America;
Figure 4
He wrote [link]
“I attach a plot that shows climate around the US. The blue circles show locations where the trend line has indicated cooling weather over the last 100 years. The red crosses show where it has warmed. The fact that ⅔ of the spots are warming illustrates that global warming is real, although to be careful and scientific we have to avoid the heat island effects (not part of global warming) and average equally over all land and sea. The cooling parts on the map don’t indicate that the world is cooling, but only that local variability in climate is still larger than the global warming trend.”
Now neither America nor England constitutes the entire world land surface of course, but both countries have especially good weather records. In Britain’s case, the temperature records go back to 1659, which I reconstructed further back to 1538 in this article from 2011 The Long Slow Thaw.
This showed the oscillation of temperatures throughout the period and in particular the depths of cold in the ‘Little Ice Age.’ (The results can be seen in Figure 6, below.)
The keepers of the CET records-the UK Met office had recognised that since its inception over 350 years ago, Britain – and more specifically England – had become much more urbanised and accordingly made adjustments to the temperatures in recent decades to compensate. In the ‘Long Slow Thaw’ I wrote this:
‘The modern era of CET is potentially showing the effects of needing a uhi adjustment greater than the Met office currently apply. * However, as we had earlier observed that instrumental records should not be considered accurate to tenths of a degree we are perhaps splitting hairs. Consequently, more accurately we should observe that the ‘direction of travel’ of temperatures, when combined and constrained by historic records, shows that at several points from 1538 there are similarities to the modern era as regards warm periods.”
*Note; Since 1974 the data have been adjusted by the Met Office to allow for urban warming: currently a correction of -0.2 °C is applied to mean temperatures. The context of this UHI adjustment can be seen in this graphic showing population growth.
Figure 5
The same data is shown below, excluding the population data which somewhat distorts the axis of the graphs
Figure 6
In considering the urbanisation factor used, it can be noted that the current population of Greater London is the same as that of the whole of England 200 years ago. The population has increased some 25% since the UHI adjustment was first made in 1974. Some 60% of the population of England lives within an hours’ drive of the Peak district which can be considered the area CET is centred on. One of the stations used in recent times, Ringway, was situated near a rapidly expanding airport. It was retired in 2004. England at 130,000sq km and a population of 55 million, is less than the size of New York state at 141,000sq km with a population of 20 million. So England, with its small size and large population could be considered one large heat island with the CET stations in the middle of it.
In consequence there appears to be a reasonable possibility that a further adjustment needs to be made to the urbanisation factor, which might slightly affect that characteristic ‘hump’ from 1990 clearly seen in Figure 6. In recent emails with the Met office I understand that during 2017 they carried out some work with regards to re-evaluating the CET daily and monthly series and current urbanisation adjustments have been revisited.
The result is that a new version of CET with supporting documentation is currently being formulated. Any differentiation with the existing series will need to be scientifically justified. Making any adjustments to the world’s longest running temperature series is not undertaken lightly, so it is unlikely we will see the results of this investigation in the near future. The immense amount of scientific analysis that goes into making adjustments to the record can be seen in this 2005 paper written by Met Office authors [link].
So it may end up that the urbanisation corrections could be larger for more recent years, but to comment on the likely adjustments, if any, would be mere speculation at this point.
Setting that issue aside for the time being, we can extract a variety of other data from an analysis of the seasons.
Figure 7
The coloured dots in Figure 7 highlight those ‘exceptional seasons’ that are at least 1.5C warmer or colder than the 5 year moving average. With a rising trend virtually from the start of both the official and extended record, fewer seasons would be counted as exceptional at the end, than at the start, of the graphic. However, that early era was said to be amongst the coldest periods in the Holocene- and should not be considered ‘normal’.
It was from around 1550 that some of the most severe periods of the LIA, with considerable glacier growth, appear to have occurred. This is illustrated in Figure 8 whose data was derived from a variety of sources including ‘Times of Feast, Times of Famine’ by E Roy Ladurie. Onto it has been superimposed extended CET. As can be seen from this graphic and the data noted in the other graphics, glacier growth or retreat does not necessarily occur only during short and sporadic periods of constant cold or warmth, but from the dominant weather characteristics of the entire period.
Figure 8
Looking again at Figure 7, what is notable is that even in the cold early period there were many mild winters. CET has a relatively small temperature spread with the greatest differences generally occurring in winter and summer and it can be readily seen that a mild winter can distort the year’s average. This most recently happened in 2015 when a fairly cool year up to then was changed by one of the warmest Decembers on record. Similarly a cold season, especially a winter, can cool down the year. If there are two or more exceptional seasons in the same year that will have a considerable impact on the average temperature of that year.
It is highly unusual for three or more seasons in one year to exceed these ‘exceptional’ temperatures, when they do, it is invariably marked by an exceptionally warm or cold year.
In Figure 9 (below) I examined the data covering the period 1538 onwards, with a particular view to looking closely at the especially cold periods. The rather vague term ‘Little Ice Age’ is something of a misnomer and is often generally applied to the exceptional cold that was thought to have lasted from around 1250 to well into the 19th century. The period around Dickens birth, his evocation of devastatingly cold winters, together with Napoleons retreat from Moscow, beaten by ‘General Winter’ are high profile examples of the latter part of this extended cold period. However, that is not the whole picture, as there were surprising interludes of considerable warmth throughout the ‘LIA’ as I noted in this article on The Intermittent Little Ice Age.
Figure 9 that follows is taken from this article.
Figure 9
The criteria for the temperature of years – ranging from warm red through to cold blu e- is shown in the legend heading the graphic. From this it can be seen that there were warm years, many moderate years, many cool years and many cold years, with the latter mostly being in the first two thirds of the period, the warm moderate years being well spread out (with a definite grouping around 1730 and especially at the end) and numerous cool ones, which again taper off towards the end. The suggested warmth at the (reconstructed) start around 1540 is tantalising and is better seen in context in Figure 6. This was said by some chroniclers to include the hottest and driest spring, then summer on record, followed by the warmest winter ever and an equally dry and hot spring and summer and autumn the following year.
The three years prior to this had also been exceptionally warm, as described in 6 of the Most Catastrophic Weather Events in British History.
What can we make of the overall extended historic picture when looking at the seasons and the individual years, augmented by the vast amount of literature and scientific studies, much of it referenced in the appendices of the articles cited above? It is that seasons, and no doubt very exceptional months, can affect the character of a year. That is to say, short periods of ‘weather’ are important in our understanding of the ‘climate’. The apparent deep freeze of the LIA from 1250 and lasting 500 years or more can be seen to be a chimera. Some winters were exceptionally cold but other seasons, and some winters, were as warm as their modern day counterparts.
There was no constant settled pattern but rather a mosaic of continually varying months, seasons and years, which at times produced a dominant theme, whether hot, cold, wet or dry, but was then replaced by another dominant theme that might be quite different. Whilst overall the cold might outweigh the warm, and this is especially so in some very defined periods, it was by no means a constant deep freeze, hence my use of the term ‘Intermittent Little Ice Age.’
What factors can dramatically affect the overall temperature record and the ‘climate’ over relatively short periods of months, a few seasons or a few years and thereby potentially shape our perceptions of an era? Two high profile possibilities are volcanic eruptions and sunspots;
Volcanic eruptions
The emissions can stay in the atmosphere blocking the sun which, depending on the season, may have a catastrophic impact in England or the near continent on the growing or harvesting of crops or vines, both of which have extensive centuries old records attached to them. In the case of crops, manorial records dating back to the 13th century are available and with grapes Le Roy Ladurie’s ‘Times of Feast, Times of Famine’ details the good and bad years dating back many centuries. These, amongst other records, can give a good indication of the likely real world impact of a major volcanic eruption, although its geographic location, prevailing winds and volume of emissions are key.
However, whilst undoubtedly a short term factor that can impact on temperatures of single months or even seasons, the longer term impact of volcanoes is perhaps exaggerated. As an example, the super volcano Mount Rinjani eruption -probably May to Oct 1257- was said by some scientists to have caused weather chaos for years around the world and even precipitated the first major phase of the LIA. [link]
However, detailed comments in Note 1 [Note 1], taken from contemporary English accounts, shows that this view is possibly misplaced:
Laki in Iceland erupted in June 1783 and continued sporadically until March 1784. [link]
There was a very hot summer in 1783 after some very mixed and often exceptionally wet weather in the preceding years and early snow in parts of the country. Then the annals of Exeter cathedral note:
1783 ‘Extra poor relief in extreme cold’
The grouping of cold seasons around that 1783 period appears to show emissions impacted on England for around a year or two, assuming these cold seasons were volcano related and not connected to what had caused the earlier unsettled weather. However, the decades before the eruption appear to show an unsettled period was already long established.
This is not to say that severe volcanic eruptions have no impact on weather, but that their impact may be overstated at times and such eruptions appear unlikely to have precipitated long term changes in the climate.
Sunspots
Sunspots are also often highlighted as prime causes of catastrophic changes in the climate that can cause a cold regime. Looking at CET there appears at first sight to be a reasonable correlation with the Maunder minimum around 1645 to about 1715 and the Dalton minimum around 1790 to 1830. However, an examination of the detailed record (see Figure 9) illustrates there were many warm seasons mixed in with the cold ones, so if sunspots did have an impact it was a sporadic one, or they were merely one of a number of possibly unrelated factors that affected the climate. Some very cold winters also often fall outside of known sunspot minima.
Other factors
Other factors that may influence the weather and climate to a greater or lesser degree include the strength and frequency of ocean events such as an El Nino or La Nina, the subsequent temperature of the oceans, strength of currents such as the ‘Gulf’ stream, Co2 levels, Cosmic rays, amount of sunlight, pollution and cloud cover, wind direction and perhaps extended periods of the chilling effects of a SSW (Sudden Stratospheric warming) possibly causing a break up of the polar vortex. So all in all there are a number of factors that shape our short term weather and may contribute towards longer term changes. Some, such as volcanoes and sunspots appear to probably have a passing and sporadic -although often very important- impact, rather than a long lasting one.
A SSW event can reverse the jet stream and in winter create intensely cold easterlies in contrast to the prevailing mild and wet westerlies in the UK. So in this scenario there are three broadly related factors; SSW’s , prevailing wind directions and the position of the jet stream, that are perhaps overlooked in their influence in shaping not only our weather but, over the longer term, the climate.
People have been studying the winds for years and there are numerous historic records concerning them. Information on the jet stream and SSW’s is mostly confined to more modern periods.
Anyone who has visited the exposed west coast of Britain will have seen the trees bent over in confirmation of the prevailing South westerly winds shown in the ‘wind rose’ (figure 10) taken at Chilthorne in Somerset in the West of England.
But what happens when those predominant ‘warm wet westerly winds’ stop blowing for a protracted time – for whatever reason – and are replaced by those from other directions? Could it cause a fundamental regime change in our climate – such as one of the intermittent periods of the LIA – that can be picked up in the records?
The possible impact of winds as a major factor in shaping the British weather and climate over the long and short term is the subject of part two of this study.
Figure 10
To summarise
The CET record demonstrates an interesting – but not climatically significant – decline since the turn of the century.
It also demonstrates that CET temperatures remain at a historically high level
A minority of countries or regions around the word have also experienced temperature declines of varying amounts and longevity, such as in America
The historic record appears to show evidence of enhanced urbanisation which may not be currently fully reflected in the appropriate CET adjustments by the Met office
There are potential historic siting concerns of one of the three stations generally used in CET although this station was removed several years ago.
The Met office appear likely to be releasing a new CET series that will account for some of these concerns
We can determine that the extreme seasons have lessened over the centuries, although that is partly an artefact of the rising temperature trend
We can see that exceptional seasons or months can affect the characteristics of a year or of a longer period
We can also see that the temperature has been generally rising throughout the official and extended CET record. If CET is an accurate global or Northern Hemisphere proxy (see Section 6 of the ‘Long Slow Thaw’) then it appears that we are experiencing a global warming trend of some centuries and the Global records from 1880 can be seen as a staging post and not the starting post for this rise.
We can determine that the Little Ice Age was rather intermittent, rather than continuous over hundreds of years and that individual factors such as volcanoes or sunspots do not always explain the marked changes in temperatures up or down.
Whether wind direction is a major factor in the intermittent Little Ice Age and in other periods through the CET will be the subject of a further paper.
RGHE theory exists only to explain why the earth is 33 C warmer with an atmosphere than without. Not so. The average global temperature of 288 K is a massive WAG at the ”surface.” The w/o temperature of 255 K is a theoretical S-B ideal BB OLR calculation at the top of – the atmosphere. An obviously flawed RGHE faux-thermodynamic “theory” pretends to explain a mechanism behind this non-existent phenomenon, the difference between two made up atmospheric numbers.
But with such great personal, professional and capital investment in this failed premise, like the man with only a hammer, assorted climate “experts” pontificate that every extreme, newsworthy weather or biospheric flora or fauna variation just must be due to “climate change.”
The Earth’s albedo/atmosphere doesn’t keep the Earth warm, it keeps the Earth cool. As albedo increases, heating and temperature decrease. As albedo decreases, heating and temperature increase.
Over 9,600 views of my five WriterBeat papers and zero rebuttals. There was one lecture on water vapor, but that kind of misses the CO2 point.
Step right up, bring science, I did.
Nick Schroeder, BSME, PE (LinkedIn)
http://writerbeat.com/articles/14306-Greenhouse—We-don-t-need-no-stinkin-greenhouse-Warning-science-ahead-
http://writerbeat.com/articles/15582-To-be-33C-or-not-to-be-33C
http://writerbeat.com/articles/19972-Space-Hot-or-Cold-and-RGHE
http://writerbeat.com/articles/16255-Atmospheric-Layers-and-Thermodynamic-Ping-Pong
http://writerbeat.com/articles/15855-Venus-amp-RGHE-amp-UA-Delta-T
Seriously? Copying and pasting the same off topic comment in multiple posts is very rude on our planet.
https://judithcurry.com/2018/02/26/nature-unbound-viii-modern-global-warming/#comment-867545
Ya’ know, WordPress is flooded by the same repetitive CAGW BS posted by the lying clueless MSM and maybe a dozen avatars dominating the conversation.
The work is 100% my own.
Put a sock in it.
NR65, I wasn’t going to touch this but now cannot resist. Went and read the first of your linked ‘papers’. You did not bring science, you brought JUNK.
1. A greenhouse works by inhibiting convection. It does not work by ‘insulation’ , which is used to inhibit conduction. A insulated hot water heater is a good example. Convection is also the main heat transfer mechanism in the troposphere, witness thunderstorms which are realy just convective cells. The only way earth can lose heat is through radiation, as spece is a vacuum in which neither convection nor conduction can occur. The misnamed greenhouse effect of CO2 is about radiative transfer, from first principles.
2. The ToA is above the stratosphere, not the troposphere. And there it is about radiative transfer, by definition. Perhaps younwere confused by the ERA, effective radiative altitude, where the GHE ceases. That is determined from satellites by radiosone lapse rate and infrared frequency ‘temperature’. Usually below the tropopause, except sometimes near the poles.
3. Your critical deconstruction of the Trenberth diagram is beyond ridiculous. There is much to criticize, but it concerns the error bars, not the basics.
Take your off topic nonsense elsewhere. Too many of us here have studied too long and hard to be taken in by your attempt to drive us tomyour drivel. BTW, want more detail on how the atmospheric GHE actually works, read essay Sensitivy Uncertainty in ebook Blowing Smoke (first third, the reser really is about climate sensativity). It even unpacks a better version of the original Trenberth energy balance diagram.
1) Actually, you agree with me. There is no RGHE. The albedo, which exists because of the atmosphere, reflects 30% of the irradiation and cools the earth same as the aluminized panel in the car windshield.
2) The atmospheric blanket creates a thermal gradient between the earth and the ToA same as through the insulated walls of a house.
NASA says ToA is 100 km, but I say 32 km because 99.9% of the molecules are below 32 km. Traditional Q=UAdT up to 32 km and S-B radiation above that.
3) The K-T diagram creates 333 W/m^2 of energy out of nothing, creates a 333 W/m^2 100% perpetual energy loop, moves energy from cold to hot without adding work. Three very clear violations of basic thermodynamic laws.
There appears to be no significant trend between 1700 and 1900, and the warming is concentrated thereafter. This is rather more like the CO2 trace. A sixty year running average would be more informative than trying to fit a single trend line to the whole period that clearly doesn’t fit either the earlier or later part at all.
jimd
It demonstrates that neither weather nor climate is consistent.
tonyb
Except in the last 100 years which is climate change by any definition.
Jimd
And the two climate changes from 1650 to 1740 were insignificant?
Tonyb
They certainly don’t look much when you average them over 50 years.
https://wattsupwiththat.files.wordpress.com/2013/08/clip_image008_thumb1.jpg?w=591&h=359
Jimmie, nice to see you recognizing that climate change predates the last 50 years (you’ve come a long way, baby… ☺)
But that last step is a doozie.
https://wattsupwiththat.files.wordpress.com/2013/08/clip_image0081.jpg
Jim
But it’s a Mann Imaginary tree step, not a real one.
Tonyb
Tonyb, the blue steps are yours.
Jim
Of course they are, but the cet temperature reconstruction goes back only to 1540 and as I said in this current article it shows some intriguing hints of a much warmer period of weather. Long enough to be climate? I don’t know.
Tonyb
Jim
You may remember my article ‘the long slow thaw’ I have never denied the climate has been warmimg but as you demonstrate with the graphic it has been doing so for 300 years or more.
The 1880 hansen record demonstrates that it is merely a staging post of rising temperatures and not the starting post.
Tonyb
tonyb, your diagram illustrates the point I am making, that the last 100 years is something else entirely, and this also reflects very well the way the CO2 forcing has grown concurrently with the temperature.
Jim, this is where AGWers begin to paint themselves into a corner. When you go beyond the pervue of the IPCC and claim anthropogenic warming all the way back to the turn of the century, it brings up a very real question about climate sensitivity. If a relatively small increase in co2 caused all that warming a century ago, then why haven’t we seen a whole lot more warming with the relatively large increase in recent decades? Seems that agw doesn’t give us a whole lot of bang for our buck. I think this is a loser argument for the agw crowd. (best to stick with our beloved IPCC’s pronouncements instead)…
That is why observations-based estimates of CS make no physical sense, and that is why they are going to go down the hole.
fonzie, it turns out one third of the effect of CO2 would have been before 1950 and two thirds after, so before 1950 there should be a noticeable warming, about one third of a degree, since we are at one degree now. One third of a degree is a little harder to spot against the background natural variability of +/-0.2 C, but two thirds is easy to see. We are now five standard deviations above natural variability.
But still, wonder off the IPCC reservation at your own peril. Hearkening to JCH’ comment, perception is everything. Observations are where we live. Before 1950, little change in co2, x amount of warming. After 1950, big change in co2, comparable amount of warming. And that’s assuming all you say is true! Still think that argument is a white elephant. (better to stick with the grand poobahs of the IPCC)…
fonzie, it is only twice as much after 1950 as before, same with the warming. All consistent.
Let’s put this here – when it is unmoderated I suppose.
https://judithcurry.com/2018/03/03/the-rise-and-fall-of-central-england-temperatures-part-ii/#comment-867684
Bottom line, Jim, CO2 up, warming not so much. (i don’t think AGWers want to go there)…
http://jonova.s3.amazonaws.com/graphs/hadley/Hadley-global-temps-1850-2010-web.jpg
JimD:
– “tonyb, your diagram illustrates the point I am making, that the last 100 years is something else entirely, and this also reflects very well the way the CO2 forcing has grown concurrently with the temperature.”
I would say the last 100 years are something entirely *not* different, and the whole series is entirely *not* concurrent with CO2 forcing:
https://plazamoyua.files.wordpress.com/2018/03/cet-tendencia-lineal-30-a-2017.png
plazaeme
Jim sees what he wants to see but I suspect we are all guilty of that.
I don’t know if you saw my chart from a previous article?
https://curryja.files.wordpress.com/2015/02/slide4.png
It is self explanatory. Jim suggested here that he would like to see a graphic with 60 year trends. This covers 70 years so is pretty close to what he wanted.
It seems to show a very long established warming of many centuries. Without prior knowledge it would be difficult to know where modern levels of co2 has an impact.
Also, as can be seen in my current article CET is doing exactly the opposite of what it should be doing this century within the parameters of rapidly rising levels of a well mixed gas-co2.
tonyb
tonyb, and if you put the CO2 plot next to that, it shows the point I was making. Yes, there are variations prior to 1800, solar/volcanic/ocean circulations, you name it. However the recent rise so far above the millennial or at least multi-century average is the thing that goes with CO2 levels.
TonyB, thanks.
I was trying to simplify. Showing “climate change”
– climate: 30 year statistics.
– change: the rate of T change in the period.
I dont see anything peculiar in the last 100 years.
https://plazamoyua.files.wordpress.com/2018/03/cet-tendencias-30a.png
http://lasp.colorado.edu/home/sorce/files/2011/09/TIM_TSI_Reconstruction-1.png
Jimmie, maybe this has something to do with it? (note the temp rise coincident with solar activity circa 1840)…
jim
We can see the upwards trend from 1650, not 1880 or 1950. that is the inflexion point.
The temperature also appears to start rising again around 1540/1550 but how far back that warming lasts I have not yet researched in the context of CET.
tonyb
tonyb, for climate change the important part is the deviation from the long-term mean. There are ups and downs of 0.2 C either side of the long-term mean around 9.1 C, but lately we see a continuing trend away from that, and at a time that also had increasing CO2. The scientists expect this, but the skeptics seem to be increasingly puzzled the longer this trend lasts. At some point they’ll break and say they thought it was CO2 all along.
… different post… different thread… but the same narrative…
I meant to put this here.
https://judithcurry.com/2018/03/03/the-rise-and-fall-of-central-england-temperatures-part-ii/#comment-867785
Oh, lordy… now jimmy has climate change going back 200 years when emissions were less than 1% of what they are today. (and i thought i’d left all the nutters behind at watts’)…
fonzie, not sure where you get that from. Examine Tonyb’s picture and see where you think the current trend started.
https://curryja.files.wordpress.com/2015/02/slide4.png
Then compare it with the CO2 trend.
https://i.ytimg.com/vi/UatUDnFmNTY/maxresdefault.jpg
Err, 1650 jim. If you use my graph of figure 5 it goes back that far. It comes complete with trend line.
So we have hundreds of years warming before co2 has any noticeable effect which you always pinpoint as 1950 .
The warming trend started long before that
Tonyb
I put the break point at 1850, not 1650, when you use your 70-year averaged plot. Before 1850, the mean trend would be quite flat. After 1850, not so much.
Looks pretty consistent with AGW to me. For an island on the blast end of the ocean, I would say astoundingly consistent.
“A number of studies have indicated that the decreases in global mean temperature associated with a future decline in solar activity are likely to be relatively small3,4,5,6,7. However, variability in ultraviolet solar irradiance has been linked to changes in surface pressure that resemble the Arctic and North Atlantic Oscillations (AO/NAO)8,9,10 and studies of both the 11-year solar cycle11,12 and centennial timescales13 suggest the potential for larger regional effects. The mechanism for these changes is via a stratospheric pathway, a so-called ‘top-down’ mechanism, and involves altered heating of the stratosphere by solar ultraviolet irradiance. Anomalous temperatures in the region of the tropical stratopause give rise to changes in the subtropical stratospheric winds, in geostrophic balance with the modified equator-to-pole temperature gradient. This signal then propagates poleward and downward and is amplified by altered planetary wave activity8 before being communicated throughout the depth of the troposphere in the Pacific and Atlantic basins14” Inerson et al 2015. Regional climate impacts of a possible future grand solar minimum – Nature Communications volume 6, Article number: 7535 (2015) doi:10.1038/ncomms8535
Solar UV/ozone chemistry modulates surface pressure at both poles spinning up more or less winds and ocean gyres changing patterns of warming and cooling ocean surfaces and overturning circulation in the northern Atlantic and upwelling in the eastern Pacific. It is a Lorenzian forcing – a small change triggering large responses in the Earth system. The NAO has a significant influence on CET with negative values driving cold polar fronts pushing onto lower latitudes.
The cold winter of 2009/2010 is discussed by Osborne, 2010, Winter 2009/2010 temperatures and a record-breaking North Atlantic Oscillation index – doi 10.1002/wea.660. “The Central England Temperature (CET; Parker etal., 1992) for winter 2009/2010 was 2.43 °C, an anomaly of –1.65 °C compared with the 1961–1990 mean. Although there have been 56 colder winters in the CET record since 1659, none occurred during the last three decades and 2009/2010 was the coldest since 1978/1979.” Unfortunately the NAO record below doesn’t quite go back to Napoleon’s retreat in 1812.
https://watertechbyrie.files.wordpress.com/2018/03/osborne-nao.jpg
“Winter NAO index based on the difference between normalised sea-level pressure observations at Gibraltar and southwest Iceland (Jones et al., 1997;Osborn, 2006). The original series has been rescaled here so the DJF mean time series has zero mean and unit variance over the 1961–1990 period. The thick black line shows smoothed values from a 10-year Gaussian-weighted filter.”
“These low temperatures over the UK were part of a much more extensive pattern (Figure 2(a)) with negative temperature anomalies extending over many mid-latitude landmasses of the Northern Hemisphere (NH).” op.cit.
https://watertechbyrie.files.wordpress.com/2018/03/osborne-global-temps.jpg
“Temperature anomalies (degC from the 1961–1990 mean) for winter 2009/2010, (a) as observed in the CRUTEM3 land air temperature and HadSST2 SST dataset; (b) as predicted using linear regression with the NAO index; (c) the residual (observed minus predicted). To increase the completeness of the spatial fields, grid boxes with missing data are replaced by the average of their neighbouring values if there are at least four such non-missing values.”
Osborne compared ocean and atmosphere data (a) with NAO regressed temperature (b) and found that winter temperature in 2009/2010 would have been even colder if it were not for AGW. With declining solar activity – in the UV frequency especially – the expectation is for more frequent cold NH excursions this century. The upside is more frequent summer BBQ weather in central England.
Robert
Reference your last paragraph.
We have just endured a few days of really bitter weather. Considerable snow and amazing freezing ice coating trees and making the roads a skating rink. It included the coldest march day on record.
Now this was just weather, but as we spent ten minutes levering ourselves into our coats, scarves and gloves, I must admit I did remark
‘Just imagine what it would have been like without global warmimg!’
Mind you the temperatures have definitely declined over the last 15 years but as I stress that comes from a high plateau. However it is noticeable that over the last few years I have not been able to consistently grow things like tomatoes, peppers and runner beans.
10 or 15 years ago I had no problem doing this. So something is happening but whether it will continue I have no idea. Consistent barbecue summers seem a long way away
Tonyb
A generation goes, and a generation comes,
but the earth remains forever.
The sun rises, and the sun goes down,
and hastens to the place where it rises.
The wind blows to the south
and goes around to the north;
around and around goes the wind,
and on its circuits the wind returns.
All streams run to the sea,
but the sea is not full;
to the place where the streams flow,
there they flow again.
All things are full of weariness;
a man cannot utter it;
the eye is not satisfied with seeing,
nor the ear filled with hearing.
What has been is what will be,
and what has been done is what will be done,
and there is nothing new under the sun.
Is there a thing of which it is said,
“See, this is new”?
It has been already
in the ages before us.
There is no remembrance of former things,
nor will there be any remembrance
of later things yet to be among those who come after.
http://science.sciencemag.org/content/199/4326/293
Yes – I could feel the Antarctic chill on the Tropic of Capricorn – it got down to 20 degrees C thids year so far – brrrr. Winds shifted direction creating more clarity in local waters than I have ever seen and a massive Trichodesmium bloom ensued. The watermelons – however – survived and were quite tasty.
There is of course a continuum in which the “global coupled atmosphere-oceanland-cryosphere system exhibits a wide range of physical and dynamical phenomena with associated physical, biological, and chemical feedbacks that collectively result in a continuum of temporal and spatial variability. The traditional boundaries between weather and climate are, therefore, somewhat artificial.”
https://watertechbyrie.files.wordpress.com/2014/06/hurrell.png
And if we are going to average it is only sensible to average over regimes as they have different means and variance. As far as the current regime is concerned the fat lady may or may not have stopped singing – but she might need a coat for the next one.
Vanity of vanities – Maks old mate – but the 21st century is when it all changes (Captain Jack Harkness). The future is cybepunk. The singularity occurs on January 26th 2065 when an automated IKEA factory becomes self-aware and commences converting all global resources to flat pack furniture. Until then – endless innovation on information technology and cybernetics will accelerate and continue to push the limits of what it is to be human and to challenge the adaptability of social structures. New movements, fads, music, designer drugs, cat videos and dance moves will sweep the planet like Mexican waves in the zeitgeist. Materials will be stronger and lighter. Life will be cluttered with holographic TV’s, waterless washing machines, ultrasonic blenders, quantum computers, hover cars and artificially intelligent phones. Annoying phones that cry when you don’t charge them – taking on that role from cars that beep when you don’t put a seat belt on. Space capable flying cars will have seat belts that lock and tension without any intervention of your part. All this will use vastly more energy and materials this century as populations grow and wealth increases.
“Over the past decade there has been increasing realization and concern that the steady and high solar luminosity of the past century may transition to greater variability later this century (Abreu et al. 2008; Feulner & Rahmstorf 2010; Lockwood 2010). Specifically, the Sun may descend into a period of low magnetic activity analogous to the historical Maunder minimum (MM; circa 1640–1715; Eddy 1976). A resulting decrease in total solar irradiance (TSI) impacting the terrestrial lower atmosphere energy budget is linked to changes in high-latitude circulation patterns that strongly influence the
climate of Europe and the Atlantic sector of the Arctic and subArctic (Song et al. 2010; Meehl et al. 2013), and may also influence Antarctic climate (Orsi et al. 2012). Studies have also shown the importance of stratospheric response to a grand minimum (e.g., Gray et al. 2010; Bolduc et al. 2015; Maycock
et al. 2015). Over a solar cycle and certainly in response to a future grand minimum, irradiance variability at middle ultraviolet (UV) wavelengths that drive oxygen photolysis and ozone chemistry is much larger that that of the TSI. Resulting changes to stratospheric ozone abundance alter the stratosphere–troposphere temperature gradient and feed back to tropospheric planetary wave refraction, further altering climatically
relevant circulation patterns (Maycock et al. 2015). With this realization that both direct radiative and indirect stratospheric influences affect terrestrial climate under a solar grand minimum, it is important to understand how UV irradiance would respond to such a large and prolonged change in solar
magnetic activity.” Lubin D et al, 2018, Ultraviolet flux decrease under a grand minimum from IUE short-wavelength observation of solar analogs
This does of course have implications for NH temps last century and this. It is the mechanism for a far from novel idea.
“Many things can change temperatures on Earth: a volcano erupts, swathing the Earth with bright haze that blocks sunlight, and temperatures drop; greenhouse gases trap heat in the atmosphere, and temperatures climb. From 1650 to 1710, temperatures across much of the Northern Hemisphere plunged when the Sun entered a quiet phase now called the Maunder Minimum. During this period, very few sunspots appeared on the surface of the Sun, and the overall brightness of the Sun decreased slightly. Already in the midst of a colder-than-average period called the Little Ice Age, Europe and North America went into a deep freeze: alpine glaciers extended over valley farmland; sea ice crept south from the Arctic; and the famous canals in the Netherlands froze regularly—an event that is rare today.
The impact of the solar minimum is clear in this image, which shows the temperature difference between 1680, a year at the center of the Maunder Minimum, and 1780, a year of normal solar activity, as calculated by a general circulation model. Deep blue across eastern and central North America and northern Eurasia illustrates where the drop in temperature was the greatest. Nearly all other land areas were also cooler in 1680, as indicated by the varying shades of blue. The few regions that appear to have been warmer in 1680 are Alaska and the eastern Pacific Ocean (left), the North Atlantic Ocean south of Greenland (left of center), and north of Iceland (top center).”
https://eoimages.gsfc.nasa.gov/images/imagerecords/7000/7122/maunder_minimum_temperature.gif
https://earthobservatory.nasa.gov/IOTD/view.php?id=7122
We can compare this fruitful science with its creative and productive use of the abductive mode of inference with the plodding narratives and misguided trendology that are horribly over indulged in by some above.
Isn’t there an equal chance it will return to the strong mid-20th century level of activity as part of that 100 year cycle?
From the information presented above, one could also infer that the observed climate change could also be correlated simply with population increase, and that CO2 is simply a rider, not a cause. ;-)
Allan
I think population increase must have some sort of affect which I suspect is greater than the Met office allowed for. Certainly urbanised stations tend to read higher than nearby rural stations.
co2 must be a factor, but at what point the logarithmic correlation drops sharply in its real world impact is difficult to determine.
Bearing in mind the high temperatures at times in the past I suspect it was around 300/320ppm
tonyb
That kind of thinking only lasts until the person looks at a map of the fastest warming areas, which are related to reduced snow cover seasons, and it doesn’t correlate with population centers. Also you can’t blame Arctic ice loss on urbanization, but some still don’t let the facts get in the way.
https://data.giss.nasa.gov/tmp/gistemp/NMAPS/tmp_GHCN_GISS_ERSSTv5_1200km_Trnd112_1950_2017_100__180_90_0__2_/amaps.png
Excursions in CET are in the order of 1 to 2 degrees centigrade. Globally intrinsic variability is in the order of a degree or more on the millennial scale.
“Regional structure is found in the wintertime response in both experiments, with enhanced relative cooling over northern Eurasia and the eastern United States. For EXPT-B, the change in winter northern European surface temperatures over the late twenty-first century is found to be of similar magnitude to the difference between RCP6.0 and RCP4.5 projections for this region. We conclude that solar forcing may be an important source of uncertainty in regional climate projections.” https://www.nature.com/articles/ncomms8535
Globally the north-south polar blocking patterns modulate upwelling in the eastern Pacific in both hemispheres – that is the dominant source of global cloud variability (Clements et al 2009). SWCRE – shortwave cloud radiative effects – dominate with the low clouds that form over cool ocean surfaces.
http://www.climate4you.com/images/CloudCoverTotalObservationsSince1983.gif
SWCRE has been the dominant source of ocean and atmospheric warming (and cooling) in recent decades.
e.g. http://onlinelibrary.wiley.com/doi/10.1002/2016GL071978/abstract
“Recent studies suggest that low clouds in the Pacific play an important role in the observed decadal climate variability and future climate change.”
Tony, nice article. When weather is that varied by year and season, it suggests the very notion of climate as 30 year trends is suspect. The UAH monitored impacts of the 1998 and 2015-16 El Ninos further makes the same point. I don’t think it possible to sort a CO2 signal (yet) from that much noise. And the large decoupling of CMIP5 models from observations since ye 2005 (tropical troposphere, sensitivity) suggest they cannot be relied on for policy purposes.
The whole CAGW premise seems based on ‘nothing’ except warmunist belief. Except for the now cooled 2015-16 El Nino blip, temperature hasn’t risen significantly this century, yet this century comprises about 35% of the increase in CO2 since 1958. Sea level rise hasn’t accelerated best as we can tell. Arctic sea ice hasn’t disappeared. Polar bears are thriving. Sahel is greening. UK kids know snow. Meanwhile, the ‘mitigations’ are a costly disaster. Wind and solar destabalize the grid because they are intermittent and lack grid inertia, while driving electricity prices up sharply. Diesel pollutes compared to gasoline.
Rud
Interesting thought; Is the official definition of climate worthwhile bearing in mind the regular changes we can observe?
I think in a human timescale if things change for a decade that could be considered a change in the ‘climate’.
The difference between this winter and last is very marked and we came close to having a gas shortfall which bearing in mind the extreme temperatures, snow and high winds would have been catastrophic.
I am not against renewables per se, but they need to be robust, cost effective and reliable.
Our wind turbines would have had to be braked due to the very fierce winds and there has been barely any sun the last four or five days, so I don’t know where our power was supposed to come from
tonyb
The idea of climate as a 30-year construct when the weather (and hence the climate) are subject to non-coincident cycles some of which are much longer than 30 years seems very suspect. What value is really provided by the construct?
Tony, dunno about a decade but do know about ~15 years based on personal experience on my Wisconsin dairy farm. Of course years vary, but from ~1985 to late 1990s we always had lots of permanent winter snow. I bought 4 snomobiles so family could enjoy zipping around. Kids loved them. Put the snomobiles up (means clean, degas, fog engine, cover air intake, jack above shed floor the two not on the trailer) spring of 1998 (El Nino, IIRC) and never took them out again. Insufficient snow when you can only get there once in a while.
Not just me. A lot of the snowmobile club marked long distance trails in the Uplands just didn’t get marked, because were unusable.
Only in the last couple of years has there been enough permanent winter snow (min 6 inches for snomos) to think about recommissioning them. Trails now getting remarked in fall by the clubs. Now, this is just SW Wisconsin, like CET is just central England. But there is a large similar message in both.
A generation is “all of the people born and living at about the same time, regarded collectively.” It can also be described as, “the average period, generally considered to be about thirty years. [Wikipedia]
That’s probably where 30 years come from. An approximate limit of a personal experience. Few of us bother with historical records, and if we do, we can always adjust them.
Rud wrote: “ it suggests the very notion of climate as 30 year trends ”
The choice of the average over 30 years (that is, climate normals) was established in the mid-1930s, and was not chosen for the purpose it is now put.
When writing about “climate’, Köppen is more appropriate.
May need a better source for Köppen — dates are wrong in the link I provided.
See Köppen climate classification in Wikipedia for dates.
John, Chen and Chen Chen at University of Gothenburg, Sweden have a good website where they have analyzed shifts in Koppen zones over annual, decadal and 30 year periods. Bottom line, they found little shifting of the boundaries over 30 year periods. Overview and links here:
https://rclutz.wordpress.com/2016/05/17/data-vs-models-4-climates-changing/
Whoops, only two Chens, not three.
Ron
Thanks for those Koppen references.
You may have seen me on here ask Mosh if he could produce BEST data that shows what has been happening in the Koppen climate zones.
If I remember correctly he wasn’t very enthusiastic at the idea
tonyb
Colder periods, such as the Little Ice Age, are times when ice extent on land is more, ice shelves are extended more and there is more sea ice.
Warmer periods, such as now and the Roman and Medieval Warm Periods, are times when ice extent on land is less, ice shelves are extended less and there is less sea ice.
This is cause and not result. Climate changes in well bounded cycles that are natural, normal, necessary and unstoppable.
Ice core data shows ice accumulation is more in warmer times and it gets colder after. Ice core data shows ice accumulation is less in colder times and it gets warmer after.
Tony,
Congratulations on another highly detailed very rigorous article. I have some points for the discussion that I will be making on different comments so it doesn’t get too confusing.
Regarding the intermittent LIA. We do know the LIA was global and the coldest period in the entire Holocene from the number, proportion and extent of global glacier advances.
This image was sent to me by Olga Solomina. She prepared it for the 2015 review on Holocene glaciers that has 11 authors, among them glacier luminaries like Nesje, Ivy-Ochs, and Wanner. The figure was not included in the article.
https://curryja.files.wordpress.com/2017/05/figure-43.png
Whether intermittent or not, that requires lower temperatures. No other way around it.
Then we have the problem of studying the LIA at a single location. The LIA was complex and had regional variability. I have looked at numerous proxies and in my opinion four periods of general climate deterioration can be defined, separated by periods of general climate improvement. They do not exactly coincide with periods of low solar activity according to cosmogenic isotopes records, but show good agreement. They are shown in the following figures that in the end didn’t make it to my articles, but perhaps could be included in a revision.
https://i.imgur.com/j5Zyp0R.png
https://i.imgur.com/jVxYXux.png
While some authors that study the LIA identify the same periods, others don’t, so the issue is still contentious. I think they agree relatively well with your CET record, but not completely.
The reason for significant differences between periods is that other climatic factors are at play. As the second figure shows, LIA II took place at a time of a very profound long drought affecting Europe, North America, and the Indian Monsoon area. European glaciers did not grow much at that time due to lack of precipitation, while South American glaciers did grow. This period coincides with the most profound fall in TSI during the long Spörer minimum. But I will discuss the drivers of the LIA in another comment. For now suffice to say that at the LIA there was a coincidence in the lows of the ~ 2400 and ~ 1000 year cycles. This coincidence takes place every ~ 5000 years and the previous one marked the start of the Neoglacial period, as I have discussed in my articles.
Javier
One of the big surprises to me when i research it a couple of years ago was the intermittency of the LIA. So I am not Averse to the idea of their being different causes for these periods! or that perhaps they had some of the same causes and other factors were added.
I am ambivalent that sunspots were a major driving factor but they could have combined with another factor. The very long term cycles are always interesting, although it is sometimes difficult to know if they overwhelm all other climate factors or are merely secondary to them.
I am inclined to think you need a coincidence of factors to cause extremes, with some more important than others.
In this respect In order to make an analogy, i am thinking of the coastal flooding today just near my home.
There was a strong easterly wind which is not our usual wind direction. This created large waves and drove them towards shore. The pressure system that accompanied the winds was just in the right place and there was a spring tide. Add in a lot of water coming down the river and flooding results.
Take away the major factors, especially the winds and the sping high tide and it would have been a non event.
So the analogy with climate can be made whereby a basket of factors may need to coincide, such as you describe, whether a major drought, growth of glaciers or sunspots and this causes an extreme series of linked events.
As far as I can see winds are perhaps a determining factor ( but not the only one) in our weather, but whether they can recur consistently enough to cause a change in the ‘climate’ i.e thirty years or more, I am currently examining
In this respect Hubert lamb created some very interesting data regarding wind direction going back some five centuries, but for obvious reasons this ceased in the 1990’s.
To bring it up to date I have contacted such as the met office, where individual scientists have been very helpful and dr Phil jones who of course worked with hubert lamb, who has also been exceptionally helpful.
The problem is that the data lamb used on wind direction is not really kept nowadays in the same way as it was in his day so I am at risk of using apples and oranges in order to create a hypothesis.
There are very many things we don’t know about the climate and it would help to move things on if scientists would just occasionally say I don’t know but there seems to be a continual imperative to create doom ridden scenarios
Look forward to your other comments and more diagrams! The one from olga solomina was specially interesting.
Tonyb
Javier:
“This period coincides with the most profound fall in TSI during the long Spörer minimum.”
There were in fact two separate centennial solar minima in that period, one from the late 1420’s, and another from around 1550.
“For now suffice to say that at the LIA there was a coincidence in the lows of the ~ 2400 and ~ 1000 year cycles.”
The length and the depth of any given centennial solar minimum is not regulated by longer cycles.
Why is it that when I search this site for “Wien’s Law” nothing comes up! Surely Wien’s Law and the Planck function should be relevant with regards to the energy balance of the sun and earth and the absorption of incoming energy by carbon dioxide.
Had to look up Wein’s law. Peak emission frequency is anninverse function of temp. Why, as steel heats beyond infrared into visible spectrum, it goes from red hot to white hot as higher green then blue frequencies get added. RGB=> white. For the very narrow temperature range that climate change deals with (at most the lapse rate from surface to tropopause, maybe averaging around delta 120k, Wein’s law is irrelevant. All the radiative Planck emission is deep infrared over the entire range.
We have to put that myth originating from a French lie to rest once and for all. Napoleon’s Grande Armée was not defeated by generals Janvier and Fevrier. Napoleon’s troops were outside Russian territory before the first day of winter 1812.
https://en.wikipedia.org/wiki/French_invasion_of_Russia
While summer-early autumn 1812 was particularly warm, late autumn from 5 November became very cold and snowy.
French soldiers at the time only had summer equipment for the reason that they did not fight during the winter, and were thus awfully equipped even for moderate cold.
The losses were increased because the French army could not find a place were to hold the line and continued its retreat until reaching Danzig (Gdansk, in Poland) by late January 1813.
Napoleon’s army was defeated by Napoleon’s mistakes, and decimated by hunger, diseases, and desertion before being finally hit by a cold late autumn, the last nail in the coffin.
Javier
‘My campaign, led by General winter is just beginning’
The words of the tsar himself.
Whilst napoleon escaped, his army was very much slower, not helped by the destruction of their winter quarters. Many perished because of the harsh conditions as they retreated from Moscow.
http://www.bbc.co.uk/history/ancient/archaeology/napoleon_army_01.shtml
Not sure what point you are making here. It was cold. Many of napoleons soldiers died of the cold. Napoleons reputation as a great general was always resting in his own self belief and propaganda skills.
If citing ‘general winter’ as a big factor in his campaign was good enough for the tsar it’s good enough for me.
Tonyb
Tony,
The point is that winter could not have defeated Napoleon in Russia if Napoleon’s army was out of Russia before winter started. That’s a fact regardless of what the Tsar said.
And as a matter of fact Napoleon’s army was already on the retreat before the cold arrived, so the cold didn’t defeat him either. His mistakes defeated him.
I believe that monthly CET Tavg has an inhomogeneity (i.e. a mistake) of around a 0.2C sudden anomalous cooling in 2004, which is when the station composition changed:
https://diymetanalysis.wordpress.com/2018/03/03/central-england-tavg/
More generally the notion of a regional ABSOLUTE temperature is a strange one, the question of where exactly this temperature applies goes away if an average of temperature VARIATIONS is constructed instead.
Dr chase
That is an excellent web site you have that I recommend others look at.
Was that error you believe to be present, covered in the 2005 paper I cited by David Parker in my article?
Although retired he was still retaining an interest. Failing that, if Tim legg can not answer your query then Richard betts would point you to the answer
Tonyb
Tony, thanks for the kind words. Parker and Horton 2005 give the dates of changes in station composition, including the change in 2004, but of course that change was made just before publication of the paper. They must have checked data before 2004 to ensure that the change made sense, but it looks to me that enough time has now passed to see that it did not work perfectly.
Re: Volcanic forcing
Moberg’s superb NH temperature reconstruction shows the evidence for volcanic forcing.
https://curryja.files.wordpress.com/2016/09/figure-14.png
Figure 14. The effect of volcanic forcing on temperatures. (a) Reconstruction of the time and aerosol forcing of major volcanic eruptions from sulfate levels in Greenland and Antarctic ice cores (Sigl et al., 2015) for the past 2000 years. (b) Multi-proxy temperature reconstruction (Moberg et al., 2005) AD 1-1979 (grey line) with a 10 year moving average (black line) and its >80-yr slow component (red line). Light blue columns indicate the temperature reduction after the four biggest volcanic eruptions. Orange columns indicate the temperature recovery after the temperature effect of volcanic eruptions ended.
The run-of-the-mill volcanic eruption has a climatic effect that lasts for 2-3 years, but the really big eruptions, and the clustered big eruptions that characterized the LIA have a climatic effect that can last 1-2 decades. However once the effect disappears temperatures jump back up and the previous trend continues.
Volcanic eruptions are not responsible for the long term cooling trend that caused the LIA, but they can explain why the cooling started ~ 1230 before solar activity declined sufficiently, and why the Dalton period was so cold, when solar activity was not sufficiently low (not a solar grand minimum).
Javier
Yes, that is a very good graphic which fairly well follows CET.
Cooling appears to already be in place well before the 1257/8 event.
As shown in the contemporary accounts I cite, the observers note the cold and rain and snow which started before the volcanic eruption, although that event may have worsened it, It recovered soon after.
Lets be hypothetical here javier. Let’s assume these climatic forcings have the considerable impact some claimed.
Have you ever seen a serious study that shows what the temperatures would have been like if ;
A) the volcanoes had not happened
B) the volcanoes and solar activity had not occurred.
Are we saying here that if it had not been for these extra ordinary forcing circumstances, which have little comparison in the modern era, that the temperature curves we can observe in mine and mobergs graphs would have looked entirely different?
Tonyb
Tony,
No, I don’t remember any study that subtracts any of the forcings that are believed to be responsible for the LIA. They might exist but I would not have enough interest in them to download them, as I don’t put too much credit on computer games.
Volcanic forcing is becoming more contentious as there is interest in explaining the LIA in terms of volcanism, to weaken the solar case, as to leave CO₂ as the only contender for modern warming. So there are articles now using models to show that volcanic eruptions can have effects over oceanic variability that can last centuries. It appears the ocean is always hiding something convenient for those people hypothesis.
It is my opinion that without volcanic forcing the curve would have been quite similar with less cooling at the periods of high volcanic activity, like the Dalton period.
If we also take out the unusually low solar forcing, what is left? Without external forcing the LIA can’t be explained by our current knowledge. Which doesn’t mean that it couldn’t happen. We can’t explain the 4.2 kyr event either. In theory increased oceanic turnover can provide that level of cooling and much more. The ocean is incredibly cold and big, but there is no evidence that something like that has happened. The 1500-year cycle contributed to the LIA by increasing storminess, but I don’t think it is sufficiently strong. I can’t find a clear signature for the 1500-year cycle on temperature reconstructions due to the noise. Only specific proxies show it.
This is the record for storminess that shows the effect of the 1500-year cycle on the LIA. It has been well described by a couple of papers. I just put the data together.
https://curryja.files.wordpress.com/2017/09/figure-75.png
Figure 75. The 1500-year storminess cycle. a) Five Holocene widespread storm intervals defined on the basis of nine independently dated records of northern coastal Europe storm activity. Source: P. Sorrel et al. 2012. Nature Geosci. 5, 892-896. b) Score of the seventeen independent storminess studies for the North Atlantic and Western Mediterranean compiled from the literature in S. Costas et al. 2016. Earth Planet. Sci. Lett. 436, 82–92. c) Figure 10 from Costas et al., 2016 displaying the periods of high storm activity as black boxes for the seventeen studies that are the basis for the score analysis in b. For the identification of the individual studies see the source. DO periodicity is indicated with continuous grey lines. Dashed and dotted grey lines represent harmonics of the DO periodicity. Arrows indicate storminess power at the 750-year harmonic.”
DO is Dansgaard-Oechsger. The LIA was also the stormiest period in 6500 years.
Javier
Yes it is computer games territory but without the model simulations there would not be a climate ndustry.
I have looked through the literature to see the claimed effects for volcanic forcings. Giff miller who is one of the big proponents of the effects of volcanoes reckons the series in the mid 1200’s precipitated the little ice age.
Various commentators reckon they had an impact of from half to one degree centigrade on global temperatures but rather more on northern hemisphere and especially European ones.
If you look at your moberg chart and put those sort of figures on top of the anomaly being shown, not only would the lia not have happened but it would have been as warm or warmer than today. When cooling from volcanic forcings and solar coincide, you can put another half a degree on top of that.
Curious. I wonder why no such reconstructions seem to exist?
Tonyb
Without external forcing the LIA can’t be explained by our current knowledge. Which doesn’t mean that it couldn’t happen.
The data to explain the LIA is in the Greenland ice cores. Ice accumulation was more during the Medieval Warm Period. Ice accumulation became enough to cause a ice advance. We know the ice extent increased as the LIA got colder. It was not a result of colder, it was the primary cause of colder. Glaciers always flow. When the ice accumulation in warm times exceeds the thaw rate, the the flow rate becomes more that the thaw rate and ice advances. None of you consider the ice as a contributing factor. You are wrong about that.
Glaciers advance when ice on top is heavy enough to cause flow rate to be more than thaw rate at the lower extremities. Glaciers retreat when ice on top is depleted enough to allow flow rate to be less than thaw rate at the lower extremities.
This is never considered in climate theory or models.
You get more ice on top when oceans are more thawed and ice accumulation rates are high. You get depleted ice on top when oceans are more frozen and ice accumulation rates are low.
You can read hundreds of pages of climate theory with calculations and graphs and not find ice or flow rate or thaw rate. It is as if no one ever studied ice core data which are the best proxies we have.
LIA was also the stormiest period in 6500 years.
Ice core data clearly shows that there was more ice accumulation during the Medieval Warm Period and less during the Little Ice Age. LIA storms had less rain and snow because oceans were more frozen. You must have a source for moisture. Harvey produced more rain because oceans are warmer. The LIA could not compete with this. People rank storms worse when it is colder but precipitation cannot be more when the source for much water is frozen over. Data shows more precipitation in warmer times, even in the most recent hundred years.
LIA was also the stormiest period in 6500 years. I consider that very wrong. The storms were colder, but with less precipitation. Some of the floods may have been worse due to meltwater joining the precipitation.
If there was a large tropical volcanic eruption in 1257, I would look for a very cold winter 1256-57, and a milder winter 1257-58 following the eruption. Volcanoes don’t explain any LIA cold winters, the reverse is true, larger eruptions tend to follow the colder winters.
Page 90:
https://wattsupwiththat.files.wordpress.com/2011/09/weather1.pdf
Ulric
If you follow the link to note 1 under the sections on volcanoes you will come to the contemporary accounts of the weather of the time. I think I have sent you these in the past?
Anyway, the weather before and after the eruption in 1257/8 is as you describe.
It breaks down in the January 1258 and there was then a very cold spell which lasted a long time. 1259 was quite mild.
tonyb
Javier,
“Volcanic eruptions [..] can explain [..] why the Dalton period was so cold”
One cold summer. Tropical eruptions tend to slightly warm NW Europe winters.
Yes, but they cool the summer everywhere. Their cooling effect trumps their warming effect.
Low solar activity does not cause ice ages. More ice extent causes ice ages.
Solar activity does cause blips in the temperature but the little ice age lasted hundreds of years and the solar blips did not continue that long.
That sounds like a chicken and egg situation. What caused the greater ice extent in the first place, reduced solar activity ?
I am being devils advocate here, as the temperatures waxed and waned during the various sunspot episodes. I need to be convinced they were the main factor but they could have worked in harness with other factors
Tonyb
I like the chicken and egg story. I go to the ice core data. In warm times, like the Medieval Warm Period, ice core data shows ice accumulation is much more than in cold periods. Ice volume increased, ice piled up and got heavier and heavier. The more ice weight caused the ice to flow faster than ice was thawing. This increased ice extent. Earth got colder as the ice extent increased.
You asked: what caused the greater ice extent in the first place. That is Occam razor simple, more ice volume and weight from more ice accumulation in a warm time caused ice to advance faster than it was thawing.
Actual ice core data shows this to be correct.
What caused the greater ice extent in the first place?
Greater ice volume and weight and resulting increased ice flow is always the cause of greater ice extent.
If it got cold first, oceans would become more frozen, snowfall would become less, ice would deplete due to lack of replenishment, ice would retreat and warming would occur.
Popes
Yes, what is chicken and what is egg? Have you ever submitted a paper to Judith? I seem to remember you linking to a conference you were involved in but that was a year or two ago
tonyb
I presented this at two conferences in 2016
https://www.dropbox.com/s/8sb2yq2sk3ih7t9/Alex%20Pope%20-%20Ice%20on%20Land%20-%202017.ppsx?dl=0
So… what we’re learning now is what has been said by others from the beginning (and, I think Roger Revelle figured it out before he died whereas Al Gore flunked the course, Common Sense 101)– that temperature is an intensive variable and whole idea of an average global atmospheric temperature is meaningless.
Well, sort of yes but sort of irrelevant. IMO your critique fails for a very basix reason.
Temp is an intensive heat property of a specific place. True. Manaus Brazil is not equal to Barrow Alaska. Mile high Denver is not equal to Vail although both are in central Colorado, because of elevation lapse rate. Sure. But that is not what is compared in climatology. Each unique place local intensive heat record is averaged over 30 years (and which 30 matters greatly for comparisons) and then the anomaly plus minus from that local climatology average is computed going forward. Those Anomalies are globally comparable, because the intensive nature of local hear/temp (for example, the heat content of air depends on its humidity) is mathematically washed out by the procedure.
Now, anomalies can also hide many sins, especially the realism of climate models. See essay Models all the Way Down in ebook Blowing Smoke for examples. But not as you argued in your comment. Regards.
Globally is the only what to look at it because looking locally, all you’re measuring is the UHI effect modern living– even assuming the location of official thermometers meet established standards..
Reblogged this on Climate Collections.
“With regards to cooling, some one third of stations worldwide showed a trend that was downwards, rather than upwards. This was confirmed by Richard Muller of the BEST project several years ago”
Where are the warming stations located? In urban areas? Part or whole of local warming trend could be UHI effect. But deurbanization is unlikely the cause of cooling. World population grew from 1.7 billion to 6.1 billion in the 20th century. People don’t live in caves. They build big cities and asphalt roads radiating infrared. You can even cook egg in hot asphalt road if you cover it with glass to prevent air cooling.
“Where are the warming stations located? In urban areas? Part or whole of local warming trend could be UHI effect. But deurbanization is unlikely the cause of cooling. World population grew from 1.7 billion to 6.1 billion in the 20th century. People don’t live in caves. They build big cities and asphalt roads radiating infrared. You can even cook egg in hot asphalt road if you cover it with glass to prevent air cooling.”
1. These were primilimary results done on raw data.
2. The time period required was 75 years
a) the 75 years cound have been from 1850 to 1925
OR, ANY 75 year period. They are NOT
the last 75 years.
3. UHI was elimated as a cause.
4. Once station data was corrected, the phenomena was further isolated
to a few geographic areas ( US southeast)
mosh
I was hoping to flush you out from your Bitcoin empire. :)
I know the one third of stations cooling (worldwide or strictly regional) is hung with caveats (which I hoped I made clear) but it would be interesting to see a map of them similar to the one I linked to in my article from Ric.
hard Muller
tonyb
“UHI was eliminated as a cause.”
To eliminate UHI, you have to know the UHI effect on each station. It is not constant in all stations. How did you do that? If an average adjustment was made, how did you get the average without determining the UHI effect on individual stations? Just remove all stations in urban areas with over 10,000 population
Dr Stranelove
Good questions. I doubt Mosh will reply but let’s see
tonyb
Let’s UHI until we get the answer political conservatives demand.
jch
I don’t think I’ve ever seen an article from you here despite your knowledge. how about doing on the ‘cooling’ stations in the absence of Mosh?
tonyb
I find the cooling stations completely unremarkable. Long enough?
We should be looking for economic heat islands. Heat islands, like the ghe, seem to be stronger when starting from a lower absolute value iirc. We should look at effects from various types of economic activity.
dr strange.
simple. i picked thousands of stations that have no population. miles frim even small towns. with no human built structure close by.
next.
We don’t need no stinking UHI. We got Trump rules.
Just eyeballing that Map of the US you can clearly see major cities. They are blobs of red crosses. San Diego, San Francisco, Detroit, Chicago, Washington DC, New York, Boston. Florida is particularly interesting-
clearly visible are Jacksonville, Miami/Ft Lauderdate and Tampa.
A lot of red along the coasts. In the US south, not many people lived next to the coasts- bugs but also ability to get there. Until relatively recently. Miami, Florida, is only 122 years old and didn’t exist until someone ran a train track to the beach.
That still leaves a bunch of red crosses- Canadian interior in particular. But it’s fascinating how easily you can see where the cities are on a map of 100-year warming.
A trend profile of the CET and its relationship with emissions
https://ssrn.com/abstract=2951507
https://ssrn.com/abstract=2956179
Well done – you should summarize and submit it to Judith.
Just a suggestion.
“The Hurst effect is frequently taken to be synonymous with Long-Range Dependence (LRD) and is typically assumed to be produced by a stationary stochastic process which has infinite memory. However, infinite memory appears to be at odds with the Markovian nature of most physical laws while the stationarity assumption lacks robustness. Here we use Lorenz’s paradigmatic chaotic model to show that regime behavior can also cause the Hurst effect. By giving an alternative, parsimonious, explanation using nonstationary Markovian dynamics, our results question the common belief that the Hurst effect necessarily implies a stationary infinite memory process.” https://www.nature.com/articles/srep09068
Robert
Yes its good.
Did you follow the link in my article to here?
https://curryja.files.wordpress.com/2018/03/2a.pdf
This shows seasonality in great detail. The commentator uses the Daily temperature whereas I use the monthly data which enables us to back track to 1659 rather than 1772 when Parker started his daily series. Both are valid and the commentator has produced a very nice paper.
I don’t think there is much difference in the net effect between the two sets of data. We can observe over some 350 years the evolution of the seasons in CET and that they generally warm, but some show different trends to others at different times (hence my interest in exploring wind directions to see if that accounts for it)
The generally downwards trend since 2000 is therefore a little surprising as it affects most if not al seasons.
tonyb
Reblogged this on WeatherAction News and commented:
Another great read from TonyB. Looking forward to the rest of the series
Another great read from TonyB.
+1 and it couldn’t have come from a classier guy…
I’m a bit sceptical of the notion of cooling in some areas, having seen a lot of station records that appear to have cooled recently, but only because of relocations from urban-compromised sites to out-of-town places.
you must remember that a great many sites started in relatively rural locations such as in fields next to universities or in a green space convenient for the often weathy noblemans observers) residence. These then became built up and were compromised. Some moved often to locations not similar to ones they had left such as in a walled garden or on a higher or lower location.
In modern days many stations moved to those well known cool spots (sarc) next to airport runways or within the mass of buildings that comprise the airport complex.
Cet takes these into reasonable account, although as I say I suspect-like probably other locations-more note needs to be taken of the uihi effect than has appended.
tonyb
“Looking at CET there appears at first sight to be a reasonable correlation with the Maunder minimum around 1645 to about 1715 and the Dalton minimum around 1790 to 1830. However, an examination of the detailed record (see Figure 9) illustrates there were many warm seasons mixed in with the cold ones, so if sunspots did have an impact it was a sporadic one, or they were merely one of a number of possibly unrelated factors that affected the climate.”
The bulk of negative Arctic and North Atlantic Oscillation conditions during solar minima are well constrained by sunspot cycles. In the Maunder Minimum, from a sunspot cycle maximum around 1672 through to a sunspot cycle maximum in 1705, broken by a very warm year at a sunspot cycle maximum in 1686. In the Dalton Minimum the bulk of negative AO/NAO was 1807-1817, between the max’ of cycles 5&6, and in the Gleissberg Minimum 1885-1895, between the max’ of cycles 12&13.
In the first half of SC5 (SC12) and the second half of SC6 (SC13), there were far fewer cold anomalies.
My findings on the ordering of solar cycles and solar minima, which Tony kindly came to look at briefly a few years back, shows that the bulk of negative AO/NAO in Maunder should occur 1672 to 1705, exactly as CET shows. Much of the 1650’s and 1660’s were warm, hardly solar minimum weather.
https://climexp.knmi.nl/data/tcet.dat
CET is not always a good solar proxy in winter though, strong blocking can give positive NAO while AO is negative, like Jan-Feb 2014, and its fine analogue in Dec 1876 and Jan 1877.
1807-1817 in the Dalton Minimum coincides with a concentration of years with zero aurora observations, suggesting that solar coronal hole activity was highly suppressed. Page 11:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.641.5823&rep=rep1&type=pdf
Ulric
I was hoping you were going to write a couple of articles that explained your findings. Did you ever write them?
If so please give me a link so I can properly archive them in my active file
tonyb
I have been filling in missing pieces, finding the right correspondence for each sunspot cycle minimum. and identifying a 3453 year cycle of solar minima, based on the synodic periods of the four bodies that dominate the ordering of sunspot cycles. I’ll have it all documented on a public link over the next few months.
“The grouping of cold seasons around that 1783 period appears to show emissions impacted on England for around a year or two, assuming these cold seasons were volcano related and not connected to what had caused the earlier unsettled weather.”
The only season that those near surface aerosols impacted was summer 1783, by making it hotter, much like the forest fire smoke in Moscow in summer 2010. By Autumn the fumes and ash were blowing northwest away from Britain. Winter 1783-74 has fine heliocentric analogues in the winters of 1962-63, and the two times the River Nile froze in 829 and 1010 AD. It’s the Sun going quiet for a season.
A fascinating article that coincides with my own work relating to the correlation between annual temperature and wind direction. I have taken my own records from the last 11 years from the Baltic coast and re-assigned daily temperatures to wind direction rather than date. Using monthly averages per wind direction I have then reconstructed a theoretical annual temperature. The correlation between actual and calculated is quite astounding!
Paul
I would be most interested to see your work. Getting hold of English wind records has proven problematic and makes it difficult to correlate (or not) the wind direction and temperatures sine the 1990’s.
my address is
tonyATclimatereasonDOTcom
tonyb
Is it just me know that thinks that a mere 30 years does not constitute a valid view of climate? 300 years may just, and only just, give a view of climate
Rob Johnson-taylor “a mere 30 years does not constitute a valid view of climate?”
Seems not just you. IPCC scientists didn’t think so at one time, but it then became convenient:
Representing Uncertainty in Climate Change Scenarios and Impact Studies
ECLAT-2 Workshop Report No . 1 Helsinki, Finland, 14-16 April 1999
Edited by : Timothy R. Carter , Mike Hulme and David Viner
Published by the Climatic Research Unit, UEA, Norwich, UK. September 1999
“Representing Uncertainty in Climate Change Scenarios and Impact Studies”
Mike Hulme and Timothy R. Carter
Some take aways,
“Climatologists commonly describe the present-day climate using observations from a recent thirty-year period (e.g. 1951-80 or 1961-90). The performance of GCMs at simulating present climate can be tested with reference to such information, although measurement errors, interpolation errors and sampling errors lead to considerable uncertainty regarding the true baseline climate (e.g. New et al.., 1999).
Climate is also known to vary naturally on multi-decadal (e.g. 30-year) time scales and for reasons that have nothing to do with anthropogenic forcing.
Determining what is the true level of natural climate variability on 30-year timescales is not therefore straightforward. Observational data are limited to at most usually 100 years or so (and in any case may already contain an anthropogenic signal).
Another way of obtaining estimates of multi-decadal variability is to use multi-century unforced GCM simulations. However, with only a limited observational record and uncertain multi-century paleaoclimatic reconstructions of climate (Jones et al., 1998) available for comparing with model outputs, it is difficult to judge how effectively such model simulations represent the true natural variability of climate.
SUPPRESSING UNCERTAINTIES
This is a dangerous practise, which unfortunately is widespread in climate change scenario construction and application. The suppression of uncertainty may be deliberate or inadvertent.
Richard Katz: (Environmental and Societal Impacts Group, National Center for Atmospheric Research
“Jaeger et al. , (1998) assert that uncertainties in climate change are so pervasive and far reaching that the tools for handling uncertainty provided by decision analysis are no longer sufficient.
Despite these strong statements about the importance of uncertainty, its present treatment is viewed as quite inadequate.”
“Uncertainties in Social and Economic Projections ” Arnulf Grübler
International Institute for Applied Systems Analysis
“Over a century time scale, current states and trends simply cannot be extrapolated. The only certainty is that the future will not be just more of the same of today, but will entail numerous surprises, novelties and discontinuities. Even if probability distributions can be constructed, they are inherently subjective and also time dependent.
To quote Henry Linden: “The probability of occurrence of long-term trends is inversely proportional to the ‘expert’ consensus.”
“Uncertainty in Representing Observed Climate”
Mark New, Climatic Research Unit, School of Environmental Sciences, University of East Anglia
..it is conventional to use a 30-year period for the construction of datasets of climatological means and variances. In the presence of multi-decadal climate variability a thirty-year mean may provide an incorrect estimate of the longer-term average climate.
Unfortunately, observed climate data over much of the world is limited to the 20th Century or parts thereof, making it difficult to assess these data in the longer-term context. It is only in Europe that multi-century homogenised climate records exist (Jones, 1999). The best known example is the Central England Temperature (CET) series which extends back to 1659 (Manley, 1974).
Observed climate data are typically of short duration – less than 100 years – which makes it difficult to place an observational record in the context of longer-term natural variability. This issue is complicated further because some of variance in the observational record may be anthropogenic.”
New models build upon existing models. Their errors and uncertanties are glossed over by the enthusiasm to produce an anticipated result and are carried forward as future facts.
“The NAO is essentially a measure of the variability of the zonal flow with strong zonal flow during the positive cycle and meridional Rossby wave blocking north-south patterns during the negative cycle.” http://www.mdpi.com/2225-1154/3/4/833/htm
https://watertechbyrie.files.wordpress.com/2017/01/nao_fig_4-e1520191198670.jpg
“Atmospheric scientists have maintained that winter NAO anomalies owe their existence to atmospheric processes [15]. They suggest that hemispheric winds of the NAM and SAM reflect dynamic processes that transcend land-sea geometry and the distribution and character of continents of a particular hemisphere. The NAO was thought to be a symptom of a broader fluctuation in the atmospheric mass between the entire Arctic Basin and the surrounding zonal ring [15]. In this way sea level pressure is described as a hemispheric scale seesaw of atmospheric mass between polar latitudes and the centers in the North Pacific and North Atlantic. The southern hemisphere has an identical low pressure polar area and high pressure zonal ring [15]. Generally the sea level pressure seesaw has a strong winter signature in the northern hemisphere [15] but is less seasonal in the southern hemisphere [16].” op. cit.
This is what drives major excursions in CET. Polar surface pressure seems connected to solar activity.
Robert
This just posted by David Archibald at WUWT which originally came from Ole Humlum
https://wattsupwiththat.files.wordpress.com/2018/03/image2.png
So yes and no.
tonyb
Negative NAO drives a warm North Atlantic anyway, but while a warm AMO will raise a seasonal average UK temperature, it won’t stop a particularly negative AO/NAO period from being very cold, like both ends of 2010 and March 2013. The increase in negative AO/NAO in every solar minimum drives a warm North Atlantic. You can see it on the AMO series in the late 1800’s, and ships saw a large loss of sea ice 1815-1817.
Solar Forcing of Regional Climate Change During the Maunder Minimum:
“However,
when filtered to isolate the multidecadal-to-
centennial time scales associated with the
Maunder Minimum, and lagged to allow for
inertia in the ocean’s response, the empirical
regression (Fig. 3, bottom) shows a clear
AO/NAO-type pattern of alternating cold
land and warm ocean temperature anomalies.”
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.468.6544&rep=rep1&type=pdf
https://media.springernature.com/m685/springer-static/image/art%3A10.1038%2Fs41598-017-13246-x/MediaObjects/41598_2017_13246_Fig2_HTML.jpg
The aa-geomagnetic index is a ‘precursor’ to solar activity. It is calculated from records from Melbourne and Greenwich Observatories originally.
https://wattsupwiththat.files.wordpress.com/2018/03/image3.png
It is solar activity that David Archibald is suggesting is at the bottom of this – influencing these other disparate measures. These changes seem to be a combination of wind driven gyre circulation changes and ocean baroclinic feedbacks.
“A number of studies have suggested that much of the interannual variability of the AMOC has been forced by atmospheric wind stress changes (Polo et al., 2014; Zhao & Johns, 2014a, 2014b). On longer time scales, climate simulations suggest that there are cycles of air-sea interaction in which reduced heat loss from the ocean to the atmosphere over the subpolar gyre results in less deepwater formation, thus slowing the lower limb of the overturning circulation (Roberts et al., 2013). The diminished ocean meridional heat transport leads to a reduction in subpolar gyre heat content until eventually heat loss over deepwater formation regions, such as the Labrador and Irminger Seas, increases again, reinvigorating the overturning circulation. A decline in the density of water in the Labrador Sea since the late 1990s has led to the hypothesis that a reduction of the AMOC after 2008 is part of such a cycle (Robson et al., 2013). However, variability in freshwater transport is also important in controlling density in the subpolar gyre and significant variability in mechanisms has been found in model studies (see, e.g., Buckley & Marshall, 2016; Roberts et al., 2013).” http://onlinelibrary.wiley.com/doi/10.1002/2017GL076350/full
And the mechanism is solar UV/ozone chemistry in the stratosphere connecting and amplifying through atmospheric pathways to polar surface pressure. As I discussed above.
https://judithcurry.com/2018/03/03/the-rise-and-fall-of-central-england-temperatures-part-ii/#comment-867642
So yes and yes.
Robert, best to look directly at the solar data than a terrestrial proxy. AMO cooling occurred in the early to mid 1970’s, the mid 1980’s, and the early 1990’s, during periods of stronger solar wind, and AMO warming from the mid 1990’s from when the solar wind weakened.
The solar influence on the AMOC-AMO goes in and out of phase with sunspot cycles so it cannot be dominated by UV forcing.
https://www.linkedin.com/pulse/association-between-sunspot-cycles-amo-ulric-lyons
https://snag.gy/d2v3aJ.jpg
I can’t even read this graph – and the a-a index is instrumental and not a proxy. The influence of surface pressure at the pole in the Northern Annular Mode is what drives all these other things through modulation of the north-south blocking pattern. You are not looking at the fundamentals.
The aa index chart that you have posted above is a proxy for geomagnetic storms, showing only annual days with >60 on the aa index. The aa index is a result of solar activity, it cannot be a precursor of solar activity.
https://www.ngdc.noaa.gov/stp/geomag/image/aastar07.jpg
http://lmgtfy.com/?q=The+geomagnetic+aa+index+as+a+precursor+of+solar+activity
Regarding below posts concerning aa index, what is/are the proposed terrestrial climate change mechanism(s) due to solar influenced geomagnetic activity? I have an idea, but I want to hear from you all.
Sorry, I am asking about the above posts concerning the aa index. What is/are the proposed terrestrial climate change mechanism(s) due to solar influenced geomagnetic activity? The aa index indicates degree of geomagnetic disturbance by solar inducements, not just sunspot activity. The sun can generate relatively high aa index values due to Earth directed coronal holes in the absense of sunspots; yieldiing greater solar wind changes. See the following:
https://www.ngdc.noaa.gov/stp/geomag/aastar.html
http://appinsys.com/GlobalWarming/AAIndex.htm
I have some ideas of possible effects, but I want to hear from you all.
Robert writes:
“The influence of surface pressure at the pole in the Northern Annular Mode is what drives all these other things through modulation of the north-south blocking pattern. You are not looking at the fundamentals.”
Don’t teach your grandmother how to suck eggs.
https://www.linkedin.com/pulse/association-between-sunspot-cycles-amo-ulric-lyons
Solar UV/ozone chemistry acting through atmospheric pathways on polar surface pressure is a Lorenzian trigger for shifts in atmospheric and ocean circulation.
The solar connection – for instance.
https://www.nature.com/articles/ncomms8535
Influences on ocean and atmosphere circulation.
http://www.mdpi.com/2225-1154/3/4/833
I am interested in mechanism not supposition.
The solar wind effects polar ozone. The overriding point is that the solar influence on the AMOC-AMO goes in and out of phase with sunspot cycles, following the solar wind strength, so it cannot be dominated by UV forcing.
As I say to people quite often – I can’t take your word for it and would need a reputable source for common knowledge or journal articles for more arguable findings.
Such sources are unanimous that the AMO is internal variability, and lack knowledge and arguable findings, it’s just an assumption.
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So much to peruse in this long view of CET temperature oscillations.
Thx Tony, Javier, et al (but not Al.) Reposting @ Jo Nova.
Yes, Thanks Tonyb and Javier
Lots to absorb.
But great work.
Scott
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