Guest Post by Willis Eschenbach
When I was a kid I had the great fortune to be taught to splice rope by a grandson of Richard Henry Dana. He taught me how to do a long splice and a short splice … but I never learned how to do either the long or short data splice. For that, I had to wait for climate science.
Anthony recently highlighted a paper about reconstructed Greenland temperatures called “Past 4000 Years of Greenland Temperatures“. I don’t really have a dog in the fight, but I was greatly amused by their description of what they call “in situ observations”.
Here’s the top panel of their Figure 1.
Figure 1. ORIGINAL CAPTION FROM THE PAPER (top) Reconstructed Greenland snow surface temperatures for the past 4000 years and air temperature over the past 170 years (1840–2010) from three records. The thick blue line and blue band represents the reconstructed Greenland temperature and 1s error, respectively (this study). The reconstruction was made by two different methods before and after 1950. The “gas method” is as described in section 2, and the “forward model” is described by Kobashi et al. [2010]. Thick and thin black lines are the inversion‐adjusted reconstructed Summit annual air temperatures and 10‐year moving average temperatures, respectively [Box et al., 2009]. Thin and thick red lines are the inversion adjusted annual and 10‐year moving average AWS temperature records, respectively [Stearns and Weidner, 1991; Shuman et al., 2001; Steffen and Box, 2001; Vaarby‐Laursen, 2010]
I thought “hmmm, data from the summit of the Greenland ice cap, didn’t know about that” … so I went to find out what their data consists of, the famous “thin red line” in the Figure 1 above. Here’s what they say about the “in situ observations”:
5.1. Present Greenland Temperature
To place the Greenland temperature proxy reconstruction into a historical context, we incorporate two additional Summit temperature records. One record is obtained from a compilation of Summit Automatic Weather Station ∼2 m surface air temperature (SAT) observations (hereafter AWS or in‐situ record) that spans 23 years (1987–2010). The AWS were situated within 20 km of the GISP 2 coring site and within 25 m elevation of the ice sheet topographical summit (Figure 1, top, red line).
The series begins in May 1987 with Automatic Weather Station data after Stearns and Weidner [1991].
Shuman et al. [2001] merge this record with data from the Greenland Climate Network (GC‐Net) AWS data [Steffen and Box, 2001] to produce the first 12 years of this compilation.
Gaps before June 1996 are in‐filled using daily passive microwave emission brightness temperatures.
GC‐Net data then comprise the period spanning June 1996 to December 2003 with gaps in‐filled by Danish Meteorological Institute (DMI) Summit AWS data [Vaarby‐Laursen, 2010].
The DMI data exclusively form this data series from January 2004 through December 2010.
Man, I thought, that is a curious provenance for the summit temperature data. First, 12 years of observations, with gaps in-filled using satellite microwave observations. Then from 1999 to 2003 the summit temperature was estimated using surrounding stations. Gaps in the surrounding station data are infilled from the DMI Summit station data. Then from 2004 on, we have DMI summit station data only.
So I looked a bit deeper. It gets better. Remember the Shuman et al. observations that form the “first 12 years of this compilation”? It turns out that it was not one station, but three stations … and there was no overlap between the stations to compare temperatures. The Shuman paper is here. Their Figure 2 shows those first 12 years of the record, from three AWS stations: CATHY, GISP2, and SUMMIT.
Figure 2. Automated Weather Station records near and at the Greenland Summit.
Note the lack of overlap and the number of gaps, covering days, weeks, or months. Here’s Shuman’s description of what they did:
In order to complete a temperature record from the Greenland Summit (May 1987 to October 1999), it will be necessary to adjust the AWS Cathy temperature record to account for the difference in its location as well as to complete the AWS GISP2 and AWS Summit records across multiple periods of missing data .
The methods detailed in Shuman et al. (1996) or in Shuman et al. (1995), which rely on appropriately located and contemporaneous SSM/I brightness temperature data (Table 1), will be used to achieve a complete and consistent temperature record.
Inconveniently, SSM/I data are not available from 4 May 1987 to 10 July 1987 and are missing from 3 December 1987 to 13 January 1988 (Table 3). Smaller gaps in the SSM/I or AWS record of less than 5 days will be dealt with by interpolation.
So for the 23 year record we have a long data splice as follows:
2 years of AWS CATHY data,
7 years of AWS GSIP2 data,
3 years of AWS SUMMIT data,
5 years of estimated data, and
6 years of AWS SUMMIT data.
All of this is “infilled” from a couple of sources.
Now, remember that this data is what they are using to calibrate their algorithm that converts ∂O18 data into temperature data …
The authors of the study cite Ellen Vaarby-Larson 2010, which is here. It shows the Summit temperature for the period 1998- Feb 2010:
Figure 3. Air temperature from the 04416 Summit AWS station. From Vaarby-Larson 2010.
Note that even in the modern period there are gaps of up to about a year in the record. (Also of note is that there are only about six three-hour periods in the record where it is above freezing, and that the summer/winter spread is about 60°C [108°F]. Yikes!) Here’s an example of why the record contains so many gaps and spaces:
Figure 4. Condition of the Summit station 04416 during the 2007 annual visit. From Vaarby-Larson 2010
Let me conclude by looking at some other problems endemic with AWS records. I cannot improve on the words of Ms. Vaarby-Larson, who said (op. cit.):
Recommendations
Generally, great care should be taken when using the observations from station 04416 Summit, since the observations are influenced by:
• Extreme climatic exposure of the station measurement equipment (the extreme cold causing e.g. low availability of wind observations during winter)
• Non static barometer elevation above sea level, due to the Greenland Ice sheet flow-patterns
• Non static height of measurements above ground, due to burial of the station by snow falling
None the less, the observations of temperature, humidity and wind (see Figure 10 – Figure 16 ) show no great, obvious shift in level or variance, at the individual station relocations in 2005, 2006, 2007 and 2009.
Any existing bias due to change in measuring height above ground, might be difficult to identify since:
• 04416 Summit only issues synop every three hours.
• There’s no direct measurement of the ongoing change in actual measuring height above ground, in-between station relocations.
• Change in weather conditions might produce the same signal in the observations
• Natural variability shows e.g. great temperature variance during winter compared to summer, please confer with the early attempt at investigation of temperature variance in Figure 17.
Hmmmm …
In a recent post called “A Modest Proposal—Forget About Tomorrow“, I discussed a paper that showed why even perfect “fitted” or “calibrated” models may not have predictive (or reconstructive) capabilities. In the current case, they are reconstructing the Greenland temperature based on a collage of actual observations, nearby observations, estimates, and satellite microwave brightness.
Let me be clear that there is nothing inherently wrong with putting together a pastiche composed of a variety of estimates and local observations and satellite data. There may even be something to learn from such a collation of disparate elements.
My point is that it doesn’t engender confidence when said pastiche is used to calibrate an algorithm designed to transform an ice core ∂O18 record into a temperature reconstruction. Even with the best of data, that’s a tough sell.
My conclusion? Only have one.
The confidence intervals in the original paper on historical Greenland temperatures are way too narrow.
w.
PS—Ya gotta love the Google Earth image of the Greenlad Summit temperature measuring site (Station ID# 04416), found here:
When I first looked that that I thought “They left out the satellite part of the image” … then I realized that they hadn’t left anything out. Anthony, I do believe we’ve actually finally found a truly rural temperature station …
Why does the shape of the red line in figure 1 bear absolutely no resemblance to Figures 2 and 3?
Just asking… I really would like to understand.
Looks like a white out, I can’t see the station 😉
When I initially commented that the spliced in situ data at the end might be dodgy, I had no idea just how dodgy it would turn out to be. I wonder if any of this was ever caught and discussed in peer review?
James Reid says:
November 11, 2011 at 10:40 pm
Not sure, but I think they’ve used the thick red line from Figure 1 (10 year averages) rather than the annual (or monthly) data.
w.
One of my teachers once said that it is better to have an approximate answer to a good question than an exact answer to a poor question. He so saying this did so before climate “science” began fabricating and torturing data. If one doesn’t splice a rope correctly the consequences can be deadly. In climate “science” there are no consequences.
Thanks Willis.
Lemme see Willis, we’re using a coupla stations that have been relocated, to estimate the temperature at a station that has been wonky for at least some little time, from which we estimate a terminal velocity from temperature acknowledged to be even wonkier from time to time due to known spurious responses due to whatever might be discerned from “Natural variability shows e.g. great temperature variance during winter compared to summer”.
Got it..
Seems OK to me, but I did bump my head last night……..
re Google Map
“… it’s full of polar bears!”
Apologies to Clark & Kubrick (and Dave Bowman)
This is the satellite record for Central Greenland:
Monthly anomalies
http://climexp.knmi.nl/data/itlt_315-325E_70-75N_na.png
Annual anomalies
http://climexp.knmi.nl/data/itlt_315-325E_70-75N_n_mean1a.png
Pics will be active for few days.
So Figure 1 is what peer-reviewed “climate science” looks like?
Say no more.
“I don’t really have a dog in the fight”
Then I won’t really have to compare you to Michael Vick.
What a relief. Michael Vick is the lowest form of life on this planet.
summer/winter spring is about 60°C [108°F]. Yikes!)
Doesn’t that melt the snow ??
I can understand a typo of the missing minus ( this is apparently stand practice in temperature reporting) but when you did the fahrenheit conversion you should have clicked. 😉
Something is rotten in the state of Denmark and I suspect it is the Greenland Temperature reconstruction.
Take a look at the long sweeping curves in their Figure 2 Borehole temperature reconstruction down to 2,000 metres…
Now reconcile that to their jagged surface temperature graphics….
These sweeping curves look like an artefact of depth… not a temperature reconstruction.
Take a look at the temperature range in their Figure 2 Borehole temperature reconstruction down to 1,200 meters…
It ranges between -30.9 C and -31.9 C… one whole degree variability in 1,200 metres of ice…
I never realised weather and climate was sooooooooooooooo stable.
Try to find the temperature range in their Figure 2 Borehole temperature reconstruction below 1,950 meters…
It suddenly goes out of range on the graph… what is happening here…
Are they hiding an exponential artefact increase that kicks in around 1,600 meters?
The three hourly temperature records shows an annual temperature range of over 60 degrees C…
Its a very extreme environment…
Its an environment where the concept of an Average Temperature is pretty meaningless…
And I think that is the bottom line with these Greenland reconstructions: MEANINGLESS.
It looks exactly the same on Google Earth … There are some nice pics there of the Summit Station. If I knew how, I’d paste one here for you to look at.
Juraj V. says:
November 11, 2011 at 11:47 pm
Juraj, per the READ ME file from the UAH MSU data (emphasis mine):
Note that the Greenland Summit is at 3,200 metres …
Just sayin’ …
w.
malagaview says:
November 12, 2011 at 12:41 am
Actually, the solid body of the ice acts as an integrator, so the smoothness of the borehole curve is expected.
Whether it contains valuable information on surface temperature is another question. It depends on whether the thermal properties of the actual ice match up with the thermal properties of the theoretical ice. I discuss some of the issues with boreholes here.
w.
Willis:
It would be very interesting to read your take on the Greenland dating techniques.
Dating layers in Firn is one thing… at least there are layers that can be argued about…
But once you get down into ice it is another thing altogether… no layers…
This is where the computer models kick in…
Modelling “gaps” in the record
Modelling “periods of melting”
Modelling “rates of accumulation”
Modelling “flow of the ice cap”
Modelling the “annual melt rate” at the bottom of the ice cap
Modelling an ever thinning “notional annual layer” of ice in the flowing ice cap
Basically the models are circular logic… confirmation bias… call it what you like…
The input parameters to the models are a “temperature reconstruction”!
I suspect it is another case of models all the way down…
Especially as Greenland is called Greenland because it was once GREEN.
Thanks for the feedback….
Whether it contains valuable information on surface temperature is another question.
That’s the question I am trying to answer….
That’s the question I would ask before I wasted time and money on Greenland cores….
But then this is climate science 🙂
Willis
On the subject of splicing, you may be interested to look in detail at the “dance of the thermometers” in the Central England Temperature record that is presented as the oldest temperature record in the World but is no such thing, even if it does contain the oldest measurements. It is of interest because it is managed by the Hadley (Met Office) partner in the HadCRUT series and whereas the other partner Jones claims an insignificant UHI effect the CET series since 1959 has had adjustments for UHI from 0.1 to 0.3 oC depending on time of year.
From 1772 until 1852 it was a composite stitched together from seven London sites and then until 1877 from Oxford, from when until 1930 it was made up a an equally weighted composite from three sites in a triangle from the NW to SW and SE that have different climates. In 1931 another switch takes place with Cambridge tossed out and replaced by Rothamsted – one of the oldest agricultural research stations in the World with a continuous high quality temperature record going back 120 years. This mix lasted until 1958 (when the atmospheric carbon dioxide took off) when all but Rothamsted were tossed and three more introduced and then finally (so far) in 2007 one of these replaced. Details of the compilations and corrections are here:http://www.metoffice.gov.uk/hadobs/hadcet/Parker_etalIJOC1992_dailyCET.pdf
It should also be noted that the CET graphic used by the UK Government (http://ukclimateprojections.defra.gov.uk/content/view/751/500/) shows continued warming to 2010 whereas the original complied by Hadley (Download HadCET here / http://www.metoffice.gov.uk/hadobs/hadcet/ ) shows cooling substantial cooling after 2007/8!
I spent my youth near two of the current sites and can attest that they have been subject to a major increasing UHI effect – but so too have the other sites that were rural prewar and have continually urbanized. Take Rothamsted that had a population of 11000 in 1930 that grew to 15,000 in 1950 and about 27,000 now but where as far as I can tell there has been no correction for UHI. What is somewhat disturbing is that this raw data from Rothamsted (http://www.worldclimatereport.com/archive/previous_issues/vol4/v4n20/cutting.htm ) is converted by the statisticians at that site into this “hockey stick” with the “blade” from the time it joined the CET series:( http://www.rothamsted.bbsrc.ac.uk/aen/ecn/AirTemp.htm ) when “by eye” the series has three similar warming trends. A comparison of the four stations making up the recent CET record shows that they had a similar trends until around 1992 when they diverged with Rothamsted showing a major warming trend whilst Cambridge, the station it replaced went in the opposite direction and that Malvern that shows a cooling trend was replaced in 2007: http://www.anenglishmanscastle.com/archives/004438.html
Since the CET record is said to reflect the NAO, and as such can be taken as a proxy for the global record, the analysis of these series deserves more attention, especially the discrepancy between the partners in HadCRUT over corrections for UHI
malagaview says:
November 12, 2011 at 1:19 am
Dating is tricky. However, a variety of different methods are used and compared for agreement. There’s a paper here (PDF) whose abstract says (emphasis mine):
Since they give error measurements, that allows you to see how the dating error might affect any particular results that interest you. In any case, download the cited report, it will answer each and every one of your questions, and you can make up your own mind.
w.
Actually, the solid body of the ice acts as an integrator, so the smoothness of the borehole curve is expected.
The smooth curves indicate that ice acts as an integrator…
The smooth curves could also indicate that ice acts as an homogeniser…
In which case the smooth curves could just be an artefact of depth and pressure…
So I am wondering where are the studies that demonstrate that the argon and nitrogen ratios remain stable in “ice bubbles” when subjected to increasing pressure over,say, 4,000 years?
When you standardize a measurement the standard must be correct and accurate otherwise the end result will be wrong. To standardize an algorithm against a data set that is questionable, and some data from below surface level due to the surprise snow, is laughable.
Thanks for the link….
It’s the case of the exponentially disappearing ice…
As you get to the bottom of the ice core 98% of the ice is gone…
So I guess the bottom of the ice core is just “dust” and “bubbles”
Providing snow has been accumulating continuously for 161,313 years..
And no “ice” has melted for 161,313 years..
And the “bubbles” haven’t risen in 161,311 years…
And the “dust” hasn’t settled in 161,311…
And the ice has only “flowed” laterally for 161,311 years…
And I am happy that up to 98% of my sample has disappeared…
Then everything is looking good.
Malagaview
One of the ways they date the Greenland ice cores is by counting the individual annual layers. Kind of like counting tree rings. This has worked reasonably well down to ages of 50,000 years (or so) . Generally speaking layer counting works fairly well. The dated variations in ice and air bubble chemistry tie in quite nicely with other well dated climate sensitive proxies from ocean floor sediments, lake sediments and speleothems. Skepticism has its limits. Even a depths of 2 to 3 km and corresponding ages of up to 110,000 years the Greenland ice cores are each accurate to about plus or minus 2000 years, which might not be perfect, but its not bad either. The layer counted ages are archived and can be downloaded for free.
Why go to all this expense and set up only one thermometer? This is the difference between classroom scientists and engineers. There should be a dozen thermometers in an array that are correlated. You could even see when one of them went down or got buried. Jeesh, we have wasted 12 precious years and have to start over again. It takes 60 years before you might have a reliable record to correlate with O18 data. Also, the AWSs should be on platforms that could be raised to stay above the snow level – adjustments made for the change in elevation (hmm engineering again)
They are splicing snow surface temperatures to air temperatures. Anyone who has dabbled in the art and science of waxing cross country skis will tell you they can be surprisingly disconnected.
In tree rings, each line represents annual growth.
In ice snow, each line represents a snow event. How do we translate multiple lines into a single annual event? Is it a simple model calculation? ie total line count divided by the average typical snow events, in a Greenland year.
I feel, a little stupid, asking such a dumb question? I assume someone has radio dated organic matter in the ice layers, to confirm event layer conversion to annuals. Is there an issue here? GK
Well we are overdue for an ice age. If AGW is as effective as said then maybe it’s a good thing.
peter azlac says:
November 12, 2011 at 1:35 am
Been there … spliced that.
w.
If the ice is only 161,000 years old at the bottom it means that the whole of Greenland was ice-free as recently as that. Does no one find this remarkable?
Surely natural variation sufficient to melt or reform all the current ice sheet is sufficient to explain anything now taking place on this planet! Claiming otherwise would be very difficult to prove. There is no doubt that the claims for AG warming are all based on very short time periods, with these same time periods refused by AGW proponents as proof of any stalled or cooling global temperatures.
These simple facts are sufficient to convince me the AGW case has not yet been proven, however technically plausible it may or may not be. Enthusiastic support does not make CAGW true any more than Flat Earth or Phlogiston.
Crispin in Waterloo says:
November 12, 2011 at 10:55 am
Crispin, let me see if I can find an image to show why this is not true. Hang on … ok, try this one.
The Greenland ice cap is not solid. It is constantly in motion. At the ice / land interface, the ice is in movement towards the coast and eventual calving.
In addition, down at the ice / land interface, because of the motion of the ice there is shear and mixing going on which jumbles up the layers and makes any further dating impossible. We don’t know the age of ice at that depth, no way to tell.
AFAIK, the last time Greenland was largely ice-free was about three million years ago.
w.
A very interesting analysis of this papier mache construction of a ‘modern age continuous temperature record’ from arbitrary (I’m being kind…) spliced temperature records and proxies, and using that soggy construction to try to establish a connection to the shaky-at-best oxygen/nitrogen isotope ratio temperature proxies from the Greenland icepack. As most engineers realize early on, after their first significant failure, “The devil is in the details!” Your analysis, Willis, shows the exceptional, undocumented, and probably calculation defying uncertainty embedded in those details, rendering their analysis and conclusions essentially bankrupt and useless. Analytically, their ‘constructions’ are even less palatable than the institutional grade ‘chop suey’ served in my old high school cafeteria was! Ugh….
Thank You, Willis!
And “Thanks!” to Malagaview, as well, for your cogent contributions!
Delightful.
G. Karst says: November 12, 2011 at 7:58 am
In tree rings, each line represents annual growth.
In ice snow, each line represents a snow event.
PRECISELY!
Rob R says: November 12, 2011 at 3:38 am
One of the ways they date the Greenland ice cores is by counting the individual annual layers.
The problem is that a “layer” can represent:
1) a snowing event,
2) a melting event
3) a freezing event
So you can count layers… but that is NOT years…
You can try to backtrack “dust” to a volcanic event…
But they only managed eight “hits” on that one…
The penultimate volcanic “dust” match is for Eldgja in 934 AD…
The it fizzles out in 79 AD with “dust” from Vesuvius…
At which point there are only about 500 meters down in the 3,030 meter core
Hardly convincing…. only another 159,379 years left to worry about!
Then we have the problem that the “core is deformed below 2,800 meters”.
Unsurprisingly this doesn’t ring any alarm bells with climate scientist.
To a rationale person this represents a residual ice cap.
A residual ice cap after numerous melting events…
A residual ice cap after numerous accumulation events…
Then we have the problem of the disappearing ice age…
Greenland was the focus of snow accumulation for the ice sheet that spread down over North America in the last ice age…
That is one heck of a lot of snow and ice…
And the average notional annual layer depth between 9,374 BP and 39,852 BP is just 24.38 millimetres!
Based upon a comparison with “recent” accumulations 90% of the ice age has disappeared…
And it gets worse as you dig deeper…
And we still don’t know if “bubbles” rise in 161,311 years…
And we still don’t know if “dust” settled in 161,311 years…
And we have to guess using a computer model how the ice has “flowed” for the last 161,311 years…
And how do they do this?
By supplying the snow fall and temperatures (and much more) for the last 161,311 years…
And if they know those parameters then they wouldn’t need to look at the ice core to begin with.
At this point they have lost an ice age and all credibility.
Willis Eschenbach says: November 12, 2011 at 11:23 am
AFAIK, the last time Greenland was largely ice-free was about three million years ago.
Sorry – but that is either a big “duck out” or just plain misdirection.
malagaview says:
November 12, 2011 at 2:54 pm
I tried to answer your question honestly, and you want to insult my motives? I neither duck out, nor do I misdirect people, you unpleasant little man. Perhaps you mistake me for yourself.
That’s the last time I try to lighten your ignorance. You want answers in future, go insult someone else.
w.
Well, the fjordlands were ice-free, as they are now, plus a little more, and it was warm enough to have a dairy-and-hunting economy. They still had to go to Markuland or further south for wood. So definitely warmer than today, but we are talking central to northern Norwegian climate, not the north of France or something.
@ malagaview,
You were doing pretty well with your arguments about the science, I thought, but then you made the “misdirection” blunder.
BTW what is a “duck out”?
Maybe I am incredibly dense or something… but when I look at image 3, I seen no warming whatsoever. So, where do they get they get the red line in image 1?
Anton Eagle says:
November 12, 2011 at 5:30 pm
It’s a question of scale. The change in Figure 1 is about 2°C, which is almost invisible one the scale used in Figure 3.
w.
Willis Eschenbach,
“Crispin, let me see if I can find an image to show why this is not true. Hang on … ok, try this one.”
Wikipedia has a nice picture of the bedrock below the Greenland ice:
http://en.wikipedia.org/wiki/File:Topographic_map_of_Greenland_bedrock.jpg
from
http://en.wikipedia.org/wiki/Greenland
Since central Greenland lengthwise is below sealevel and a number of areas of the surrounding mountains are very low, we end up with glacial flow rates varying radically even when not affected by geothermal sources. We also have the situation where most of the lower levels of the glacier that is not on the outside of the mountain range is NOT going ANYWHERE!!!
Malagaview;
There are several problems here. The Norse farming methods worked well for nearly 500 years. That isn’t bad.
The Norse got along well with the Dorset and intermarried with them as archeological evidence shows. They also traded with them all along the north-eastern Canadian arctic, also discovered by archeologists.
The Norse did not up and attack the skraelings of Wineland the Great. It was a kerfuffle, as the saga clearly describes.
The Inuit, called ‘Eskimo’ or ‘cannibal’ by their Algonquian neighbors were much more warlike than the Dorset, and as they moved East, they eliminated the Dorset and Thule and then came into conflict with the Norse.
However, the Black Death opened up significant tracts of farmland on Iceland, that Greenlendings had inheritance rights to, and at this point, with the cooling climate, it was much more attractive to leave Greenland and move to Iceland.
The West Colony had already been abandoned when Bristol fishermen after bad luck on the Grand Banks, seeking slaves, were sent to the west colony by the east colony people. From this event, reports came to Norway which led to the Knutson expedition, which may or may not have reached west-central Minnesota by water. These were not Vikings, they were high medieval Norse and Shetland islanders scarce a hundred years before Columbus.
There is no evidence for a taboo against eating fish among Christian peoples, let alone the Catholic Norse. Nor is there a social class structure tied to Christianity. Over all I have to give this paper a C at best, if undergraduate work.
kuhnkat says:
November 12, 2011 at 6:59 pm
Willis Eschenbach,
“Crispin, let me see if I can find an image to show why this is not true. Hang on … ok, try this one.”
Wikipedia has a nice picture of the bedrock below the Greenland ice:
http://en.wikipedia.org/wiki/File:Topographic_map_of_Greenland_bedrock.jpg
from
http://en.wikipedia.org/wiki/Greenland
Since central Greenland lengthwise is below sealevel and a number of areas of the surrounding mountains are very low, we end up with glacial flow rates varying radically even when not affected by geothermal sources. We also have the situation where most of the lower levels of the glacier that is not on the outside of the mountain range is NOT going ANYWHERE!!!
Good image, looked like it could be a huge caldera in the the centre, so perhaps the whole island in total an old volcano. And recalling that the interglacial previous to ours is said to be hotter, the 161,000 years ago bottoming out of the ice could be during that previous glacial around 100,000 years ago, in which case the age of the bottoming out could be more accurately adjusted to that time, or the time adjusted to the bottoming out. Britain was much warmer at this interglacial too, hotter than our present one, the South more like African savannah if I recall with hippos or something in the rivers. Anyway, exploring this volcano thing:
Volcanoes in Greenland – http://www.hobotraveler.com/na_2_volcanoes-in-greenland.php
These are all around the edges and could be just all that is left of one very large volcano which blew at some time, like Santorini, but in the centre so leaving the island shape intact.
More becoming known of the present volcanic activity:
I don’t know if this is a real hot spot, like the island forming hawaiian one with the island formed moving away from and becoming detached from it. NE corner would suggest then that the island is moving southwesterly, perhaps?. Part of the movement that has Scottish rocks in the US?
And even further warm periods found:
Again, these could be tied into the now known periods of interglacials in our current ice age, around every hundred thousand years.
OOPS – I’m not going there… 🙂
No doubt they’ll let us know when they’ve sorted it out..
Willis re CET
Thanks Willis, I had not seen your previous post on CET but even after the explanation by Parker I remain sceptical of the reasons for the adjustments, especially since in 2004 they replaced Malvern with Pershore, a with a site with a different microclimate, and in 2007 deleted Ringway and went back to Stonyhurst. This gives two sites close to each other in Lancashire (Stonyhurst and Sqires Gate), one truly in central England (Pershore) and one in the SE – Rothamsted. Knowing all these sites I can say they have different climates – one can see that by the type of farming at each site: grass and cattle, fruit and cereals respectively. This is acknowledged by the Met Office from data at their regional climate site – so why claim that CET represents Central England when it does not?:
http://www.metoffice.gov.uk/climate/uk/regional/
http://www.metoffice.gov.uk/climate/uk/averages/ukmapavge.html
The two Lancashire sites will, like Armagh in N Ireland, be most affected by the North Atlantic Sea temperatures (http://www.arm.ac.uk/preprints/445.pdf ) and precipitation as they are close to the coast on the Irish Sea (that is why Lancashire is known for cotton spinning), whereas I can say from my time at nearby Cambridge, that Rothamsted is affected by weather coming off the North Sea from the direction of Russia. So CET is a mixture of apples, oranges and pears with the varieties changing with the need to keep the graph heading ever upwards, or so it seems.
This does, however, raise a serious question as to whether global temperature anomalies have any real value. Surely, apart from the politics and financial aspect, we are concernesd with how changes in climate impact supplies of food and water and this is a zonal and regional problem. Natural changes in climate over centuries are reflected in the well known climate zones that can be delineated by where crops grow – for example the growth of maize and grapes during recent warming has moved northwards by a hundred kilometres plus,reflecting the fact that apart from fertilisers, agro chemicals and plant breeding, crop growth is determined by soil temperature, water supply and heat units. This concept of regional analysis of temperature anomalies is the basis pf the Ruti project of Lanser who finds that coastal thermometers exhibit different trends to those inland, as do differences by elevation. http://hidethedecline.eu/pages/ruti.php
http://hidethedecline.eu/pages/ruti/coastal-temperature-stations.php
This goes a long way to explaining the problem with CET that mixes all three – Malvern is hill country, Squires Gate and Stonyhurst are close to the coast and backed by the Pennines and Rothamsted in on the plain.
It is important to sort CET out as it is used by some climatologists in place of Nuuk Greenland – (giving the relevance to your current paper) in determining the phase of the NAO, especially since the BEST project now claims to link changes in global temperature to those in the North Atlantic.
http://www.cgd.ucar.edu/cas/jhurrell/Docs/folland.summerNAO.jclim08.pdf
http://research.eeescience.utoledo.edu/lees/papers_PDF/Atkinson_2005_AFM.pdf
http://coast.gkss.de/staff/storch/pdf/vinther.pdf
Interesting topic, more interesting to me is how you ran across Dana the Younger, grandson of one of my very favorite authors..
He should write a book:
Master Sailing Ships in 2 Years the Dana Way
kuhnkat says: November 12, 2011 at 6:59 pm
Since central Greenland lengthwise is below sealevel and a number of areas of the surrounding mountains are very low, we end up with glacial flow rates varying radically even when not affected by geothermal sources. We also have the situation where most of the lower levels of the glacier that is not on the outside of the mountain range is NOT going ANYWHERE!!!
The geography of Greenland is very intriguing… what precisely is buried beneath the ice remains to be seen… and the dynamics of the flowing ice may be more complex (than suspected) at depth … the “domed” nature of an ice cap (higher in the middle) drives the downward radial flow… while the underlying natural rock “dish” (higher at the edges) provides resistance to this radial flow at depth. So we have two forces in opposition… the containment of the rock “dish” versus a dynamic ice “dome” which varies over time. Given the massive accumulation if ice over Greenland during the last ice age it is fairly safe to assume that the balance of these forces (at depth) was very different from today.
So now we come the “chicken and the egg” question.
Why is much central Greenland is below sea level?
Obviously, this could be the natural geography of Greenland before the ice cap arrived… or perhaps the weight of the ice age “dome” compressed the underlying rock layers to form the retaining “dish”… or perhaps the flowing ice “gouged out” a depression in central Greenland during the last ice age… who knows… and who knows how to generate a realistic computer model of ice flows over the last 161,313 years.
The other side of this geographic mystery is that there is no Lake Greenland under the ice cap.
Given the natural “dish” shape of central Greenland I would expect geothermal heat to help generate a lake beneath the ice cap… after all there are 140 known subglacial lakes in Antarctica of which Lake Vostok is the largest… even the Greenland ice flow computer models have an input parameter that represents the estimated annual melting rate at the base of the ice core. http://en.wikipedia.org/wiki/Lake_Vostok
So where has the Greenland melt water gone? Evidently it is not in a lake… therefore, it seems safe to assume that the natural “dish” in central Greenland is not watertight… the ice is melting at the bottom of the ice cap and the water is somehow “running off” Greenland into the sea… quite where and how this run off is achieved is probably buried beneath ice and / or sea level.
Given:
1) the lack of a Lake Greenland
2) the Greenland ice core deformation below 2,800 meters
3) the lack of an ice age accumulation signature in ice core
i.e. at least 90% of the “ice age” ice has disappeared
4) the known history of human settlement in Greenland
5) the increased concentration of “dirty” ice at depth
Then
It is very likely that the settled science based upon the Greenland Ice Cores is misleading (to say the least).
It seems far more likely that there have been numerous epochs where the ice cap has advanced and retreated – natural variation… the core deformation and settlement history indicate that the ice cap has been far smaller (than today) in recent history… and in all likelihood the ice cap has retreated (perhaps on several occasions) into the mountains where a very dirty “residual ice core” has been retained… through melting and ablation the residual ice core retains “dust” artefacts from bygone accumulation epochs… but the ice and the air “bubbles” from the melting epochs have long since disappeared.
In essence:
The physical continuity of an ice core does NOT guarantee the temporal continuity of the ice cap in that location… this is especially applicable in Greenland.
u.k.(us) says: November 12, 2011 at 5:06 pm
You were doing pretty well with your arguments about the science, I thought, but then you made the “misdirection” blunder.
My perspective is that we are all left blundering around in the dark when we unquestioningly accept settled science… so we can all benefit from “nudges” that challenge us to “dig” into the settled science… sometimes the “nudges” are ignored… sometimes they work… sometimes they backfire… sometimes you have to take risks if you want to move the conversation forward… and sometimes I am just perceived as a unpleasant little man… such is life… that is why I usually restrict my “nudges” [comments] to ridicule and sarcasm… trying to pursue an open minded inquiry into settled science is not a straight forward adventure – there are so many twists, turns and inconvenient bumps in the road… that is why so many “advocates” prefer to establish an extensive uninterrupted narrative that is difficult to critically address.
BTW what is a “duck out”?
Another phrase that doesn’t well… a connected phrase is “ducking out”… but that doesn’t travel well either according to an “urban dictionary… what I meant was: to avoid the issues, to ignore the issues.
Steve says: November 12, 2011 at 9:28 pm
The Norse farming methods worked well for nearly 500 years. That isn’t bad.
In this context that is the only point I was trying to establish… it is a random quote [via a Google search] from the multitude of examples that support this view of history.
The NASA Earth Observatory has some interesting insights:
http://earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/
Their temperature profile diagram explains the sudden uptick in temperatures at 1,500 meters…
This is apparently caused by “warming from bedrock” just as we arrive at the “ice age”
http://earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/Images/borehole_profile_rt.gif
From this I conclude that the ice core is morphing / flowing due to both pressure and temperature gradients… so I guess this introduces many challenges when analysing the ice core chemistry – let alone the ice flow dynamics… but luckily the Scientists have resolved these problems…
However, I am still left wondering how we can be certain that the original “bubbles” and “dust” embedded in the ice has remained fixed in-situ when most of the original ice has simply flowed away – about 90% of the original ice has disappeared at 1,500 meters.
The following ice core images highlight how the concentration of “dust” increases with depth so that “the bottom of a core (lower: 3,050 meters), rocks, sand, and silt discolor the ice”.
http://earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/Images/cores.jpg
I am left wondering whether the rocks, sand, and silt at the bottom of the ice core indicates that the ice cores from central Greenland could have been formed above a fresh water lake or a sea water lagoon… I will continue my searches… perhaps there are organic remains from the bottom of the ice core that confirm [or confound] the assumption that the last time Greenland was largely ice-free was about three million years ago.
More ice cores… more dirt… more surprises….
More support for the concept of a residual ice sheet….
Digging deeper we find:
HalfEmpty says:
November 13, 2011 at 3:35 am
Although we lived on a remote cattle ranch, occasionally and fairly regularly some unusual humanoid would wash up on our shores for some obscure reason or another, friend of a friend, who knows? In any case, I’d read “Two Years Before The Mast”, so I was suitably impressed.
w.
peter azlac says:
November 13, 2011 at 3:27 am (Edit)
Thanks, Peter. I, like you, remain quite cautious about what the CET might or might not mean.
If you’d like a better long record, you should look into the Armagh temperature series.
w.
malagaview:
You have done well and have added much to the conversation regarding Greenland’s enigmatic nature. Willis does a lot of article posts and therefore receives a lot of spurious criticism. I am sure you can understand his sensitivity to wayward remarks. Stick around. GK
G. Karst says:
November 13, 2011 at 10:21 am
Agreed and thanks, G.K.
w.
I’m an engineer and if I told my line manager that I has performed a simple measurement using three different pieces of equipement that each used three different measuring techniques, had not been calibrated with each other and which gave apparently different results but I’d nevertheless spliced them together into one big measurement, he’d think I’d gone loopy.
Ryan says:
November 14, 2011 at 2:02 am
Yeah, damn engineers are picky that way, they want all these hoity-toity real measurements and verifiable results, clearly they don’t understand how climate science works …
w.
Steve says: November 12, 2011 at 9:28 pm
Your reference to the Greenlanders going to Minnesota is interesting. Have you read Barry Fell, ‘Bronze Age America’. He specialized in stone inscriptions, and put the Vikings in Minnesota during the Bronze Age, actually as a source for copper to make bronze with. If memory serves, he put them as far west as Colorado. This seemed to be supported by a PBS show 20 y.a. on a cave in southern Colorado with multi-lingual stone inscriptions, including Viking runes.
As for the basic premise of comparing current surface air temperatures with oxygen-isotope derived temperatures from the ice it should be noted that the latter do NOT correspond with surface temperatures, but rather with the temperature at the altitude in the atmosphere where the snow crystals formed. The proper comparison is therefore instead with the oxygen-isotope temperatures of the most recent snow layers.These should be easy to obtain, but strangely I haven’t been able to find any such measurements.
Phew !! for a while there I thought they were talking about reaL Greenland Temperatures.
Good news: they are just RECONSTRUCTED Greenland Temperatures.