By Steven Goddard
The American Thinker ran an article by Randall Hoven that asked “Was the Arctic Ice Cap ‘Adjusted’? The conclusion is based on the chosen value of concentration of ice in the “pole hole” where the satellite can’t measure due to inclination. See the image below from Cryosphere Today for an example:
The statement from the article below is correct, but slightly misleading because March ice concentration near the pole is always close to 100%
If we add the “pole hole” back to the measured “area,” we would get a downward trend in area due to the change in pole hole size in 1987. If we assume that the pole hole is 100% ice, then the downward trend in March would be 2.2% per decade. But if we assume that the pole hole is only 15% ice (the low end of what is assumed), then the downward trend is only 0.1% per decade, which is not statistically significant. (The corresponding downward trend for “extent” was 2.6% per decade.) It is true that whatever downward trend there is for March is due only to these adjustments (assumed pole hole size and concentration). And whether that trend is statistically significant depends on ice concentration in the “pole hole,” an assumed value.
If you look at essentially any available March concentration maps, you see concentrations near the pole close to 100%. 15% is not a reasonable number to work with, or even 80%.
If we adjust the March area for 100% concentration at the pole hole (below) the area and extent trends agree with each other just as expected.
The title of the article is “Was the Arctic Ice Cap ‘Adjusted’?” I believe the answer is yes. The extent/area data is adjusted – but correctly. Comparing this to “CRUgate shenanigans” doesn’t seem appropriate.
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[quote Morgan (14:12:26) :
1DandyTroll (12:22:55) :
Thanks for your reply.
“It’s more a difference in the code that paints the pictures, rather than either “real or instrumental”.”
I’m not sure I follow this. Are you saying that the code that was used way back when interpreted a specific piece of data as 60% concentration, but the code used today would interpret it as 100% concentration?
[/quote]
Well, the satellites don’t actually measure ice. They measure light. The detection of ice is done by software looking at the light data. This is basically “pattern recognition”.
Change the software and the pattern will change even on the same light data.
Whether or not that’s what happened with the University of Illinois pictures used with this article, I don’t know. I’m not familiar with the history of that software. But most climate software has changed in the period covered by those pictures.
Looking at the March data shown in the article,
http://www.americanthinker.com/2010/04/was_the_arctic_ice_cap_adjuste.html
The anomolies data for areas does not match the actual data.
The satellite was changed in 1987. The measurement data shows a sudden increase in 1987. Might this not be a calibration error ?
So 1983 is supposed to be the “high ice year” of record.
UIUC Comparison Photos.
Why in the name of all that’s even quasi-intelligent do we have satellites in orbit to measure POLAR ice, that aren’t in a true POLAR orbit (90deg inclination)?
Steve Goddard (13:07:05) “Looking at GISS Greenland temperature data, my sense is that satellites came on line at a most unfortunate time. http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=431042500000&data_set=1&num_neighbors=1 ”
This is a realy excellent point and deserves more publicity. The 1979-2000 baseline looks like an atypically cold period. We’re death spiralling back to normalcy!
RE: Steve Goddard (13:07:05) :
Steve I agree. There is a tendency by some to base conclusions on a small snippet of time. The 30 years of satellite data is great for science but that 30 year window is not large enough to permit clear separation of natural cycles from any potentially anomalous and unnatural event.
When I see data reflect something like this I tend to ask myself… okay, what known potentially relevant natural cycle would go full circuit in an approximate 80 year span? I also note an apparent step increase around the early 1920s. Then I have to wonder if the effects of Mt. St Helens and Pinatubo are removed would the dynamics of the Arctic over the last 80 – 90 years and specifically the last 30 years seem quite stable / mundane?
http://leekington.com/images/GLUpernavik1.png
others …
http://www.leekington.com/images/GLTassilaq1.jpg
http://www.leekington.com/images/GLIllulisat1.jpg
http://www.leekington.com/images/RuKandalaksa.png
http://www.leekington.com/images/RuOstrov.png
The NUUK data you provided (giss) in the same scaling format as those above
http://www.leekington.com/images/GLNuuk1.jpg
bubbagyro (12:14:25) :
Starting and stopping points determine trends. It is a statistical art when to start or stop depending on ones bias. The only way to make this scientific is to do trend line analysis, or analysis of trends. This has to be set ahead of the fact to set the rules. For example, one sets a trend period using a random rule, say arriving at 17 or 27 years. Then you analyze, say, 7 periods of 17 or 27 years, each time the confidence grows and odds of chance are minimized.
Say what? We only have one 30 year period? That’s my point.
Sure, let’s predict if the climate will irrevocably changed in 2100, after 189 years of data collecting. Brilliant.
How about your doctor come up with diagnosis of lung cancer a few decades after you’re buried ? You know, after he’s sure. No hurry.
Anu – Goofy analogy. If you think about it for just a moment, you will recognize that, and why – unless you don’t want to.
Does remind us of the ‘tobacco scientists’ who stuck to their story no matter what the data showed.
Which side of this debate is most like them?
Anu (11:26:38) :
Sadly, all that’s left of WWN is an ill-maintained web site.
However, a pleasant find was http://english.pravda.ru I was under the impression it was all propaganda, but today they have stories like Girl Sleeps in Siberian Town for Nine Years Non-Stop, NASA Probe Finds Trees on Mars, and Yes! Aliens Land in Russia.
I need an iPad so I can read it while standing in the checkout line at the grocery store.
Clayton Hollowell (15:07:35) : “Why in the name of all that’s even quasi-intelligent do we have satellites in orbit to measure POLAR ice, that aren’t in a true POLAR orbit (90deg inclination)?”
Two reasons, (1) a polar orbit means the satellite can observe the polar area for only a fraction of its orbit (as it swings around the Earth from North to South), and (2) the satellite needs to transmit its data to ground receivers, there is a network in place across the world for that, but only for equatorial-type orbits. A polar orbit means it will frequently transit N to S over ground which has no receiver.
Lee Kington (15:16:15)
1979 was the beginning of a significant period of global warming, and that is the same year which the satellites came on line. As a result, all satellite temperature and ice data is skewed. Note the break in slope of gistemp around 1979.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
Also, satellite temperature data gets exaggerated during ENSO events.
http://www.woodfortrees.org/plot/uah/from:1997/plot/gistemp/from:1997/offset:-.25
So much effort to deny the obvious, it is warmer than 30 years ago (even though we don’t really know how much), and Ice extent has dropped since the 70’s. Yet it was warm in the 30’s, the MWP and the previous interglacial maximum was much warmer. Ice extent in the Arctic was low in the 30’s from anecdotal records. The warming has been a good thing, crop yields are up, forests are regrowing in much of the developed NH.
Of course, in order to counter exaggerations of the warming, seasonal weather patterns, and ice extents demise, much energy must be wasted.
The only question of interest really is what proof is there that mans CO2 (4% of annual emissions) contributes to climate change (warming, cooling, whatever). I have not seen any convincing evidence that man has caused the small amount of warming and is responsible for all the CO2 increase (perhaps natural warming caused CO2 atmospheric equilibrium to change, and it lags temperature), other than the invalid correlation is causation argument.
Less evidence is available for the runaway greenhouse effect.
B efore adopting any expensive measures to combat what may be a myth, all papers which are sited as evidence for the AGW- CO2 hypothesis whould be made available to the public for free, instead of hidden behind subscription paywalls (much of the research was probably paid by the public, or perhaps I should say borrowed to pay for).
Instead of all papers, maybe the top 100 would be better.
Clayton Hollowell (15:07:35) :
Why in the name of all that’s even quasi-intelligent do we have satellites in orbit to measure POLAR ice, that aren’t in a true POLAR orbit (90deg inclination)?
Remote sensing satellites in polar orbit commonly use a sun-synchronous orbit: so that each successive orbital pass occurs at the same local time of day. Since a typical orbit is ~1000km you get an orbital period of ~100mins giving a local time variation on each half orbit of less than an hour.
To maintain a sun-synchronous orbit as the earth revolves around the sun, the orbit of the satellite must precess at the same rate. This can’t happen if the satellite passes exactly over the pole. Given the earth’s non-spherical shape, an orbit inclined at a slight angle is subject to a torque which causes precession; an angle of about 8 degrees from the pole produces the desired precession in a 100 minute orbit, but it leaves a small hole at the poles.
Al Gored (16:01:07) :
Anu – Goofy analogy. If you think about it for just a moment, you will recognize that, and why – unless you don’t want to.
Does remind us of the ‘tobacco scientists’ who stuck to their story no matter what the data showed.
Seitz and Singer come to mind
Which side of this debate are they on?
Phil. (17:59:40)
Well, we know which side you are on: the side of climate panic.
Phil. (17:49:09) : “… Given the earth’s non-spherical shape, an orbit inclined at a slight angle is subject to a torque which causes precession; an angle of about 8 degrees from the pole produces the desired precession in a 100 minute orbit, but it leaves a small hole at the poles.”
Great explanation, leaves my prior explanation in the dust. Thanks, Phil.
Nah, that hole is where god sharpens his pencils… Saint Elmo’s fire is the bits burning off in the atmosphere…
Here’s a picture worth a 1000 emails:
http://www.robertb.darkhorizons.org/TempGr/YearlySeaIceAv.GIF
And here’s the data I computed the lines from:
http://www.robertb.darkhorizons.org/TempGr/SHEET1.XLS
And here’s the webpage where you can see the text with it:
http://www.robertb.darkhorizons.org/WhatGlobalWarming.htm
The Northern Hem Sea Ice Extent is down, but the Southern Hem Sea Ice Extent rose to compensate for it.
Almost the same thing happened for Sea Ice Area.
Looking at the Global Sea Ice Yearly Averages for both Extent and Area, nothing remarkable has happened. Both measures are very close to thier 1979-2009 average.
This is about as mundane and unexciting as a Soap Opera rerun.
In fact, it’s another AGW rerun. They just pick the stat with the most slope to prop up the theory, and jump on the PA system.
The only data points I had to interpolate were Dec 1987 and Jan 1988, so the real data for them is 11/12, or 91.6%. Blame it on El Nino.
I also did montly stats for N, S and Global Area & Extent, but the results still add up to the same thing: It all evens out. Who cares?
If the persons who portrayed the Sea Ice crisis had bothered to paint the whole picture, we wouldn’t be discussing this.
Good grief.
The story I hope to read one day will be about the changes in technology and algorithms over the years. Both the data and the methods of converting data have changed, and the way ice is estimated today is not the same as in 1980, or 1990 or 2000.
How did they graft the changes together to produce one time series?
If one used just the 1980 method throughout, how has ice extent changed?
Anu,
“Sure, let’s predict if the climate will irrevocably changed in 2100, after 189 years of data collecting. Brilliant.”
Climate science is an immature science. We only have 30 years of satellite temperature and ice extent gathering. Other satellites for measuring water vapour and energy budgets are even more recent. There are yet other satellites that are still on the drawing board, and more still that have not even been conceived. The fact is it will take a lot of time to build the datasets we need to understand climate. It makes no sense for you to get irate at other people for pointing this out.
I wonder if there has been any thought of putting up a weather satellite in a 12-hour synchronous polar orbit. Such a satellite would cross each pole and the same two opposite points on the equator twice each day.
RE: Spector (05:36:53) : “I wonder if there has been any thought of putting up a weather satellite in a 12-hour synchronous polar orbit. Such a satellite would cross each pole and the same two opposite points on the equator twice each day.”
Correction: As the earth will have rotated 90 degrees east by the next equatorial crossing, every six hours with a 12-hour orbit, I believe each equatorial crossing would be 90 degrees east of the previous crossing point. Thus it would appear that the same point on the equator would only be seen once a day.
Latest news from the Catlin Arctic Survey.
http://www.catlinarcticsurvey.com/
Hilarious!
Every pole has a hole. It they didn’t they wouldn’t be upright. Now the picture I see in the picture above is the top of the pole and not the hole without the pole. The pole must be changing, getting thicker and thinner, and that’s why we see what we see. I just can’t believe that the pole hole is getting bigger and smaller without a change in the size of the pole. That doesn’t make any sense. You know how cold it is up there. If the pole weren’t in the hole the hole would soon disappear and freeze over. Ergo, the pole is in the hole and the pole and the hole that the pole is in get bigger and smaller year to year. this is because of unrecycled plastics in the polar gyre. The more the plastics circle and rub up against the pole in the hole the smaller the pole and its hole get, but.. and this is the missing piece of data… every December Santa Claus waves his hand and everything goes back to normal –for a little while. Need I say more:-)
PS: Sorry;-)
Looks to me like the alleged hole is about the right size for Santa’s workshop, given the global population of children.