For those who love (or hate) GISTEMP‘s surface temperature product, we have this from Climate-Skeptic.com, by Warren Meyer. His interesting analysis is timely and appropriate. Surface station coverage in the areas of greatest contention right now are rather poor. – Anthony
Warren writes:
Apropos of my last post, Bob Tisdale is beginning a series analyzing the differences between the warmest surface-based temperature set (GISTEMP) and a leading satellite measurement series (UAH). As I mentioned, these two sets have been diverging for years. I estimated the divergence at around 0.1C per decade (this is a big number, as it is about equal to the measured warming rate in the second half of the 20th century and about half the IPCC predicted warming for the next century). Tisdale does the math a little more precisely, and gets the divergence at only 0.035C per decade. This is lower than I would have expected and seems to be driven a lot by the GISS’s under-estimation of the 1998 spike vs. UAH. I got the higher number with a different approach, by putting the two anamolies on the same basis using 1979-1985 averages and then comparing recent values.
Here are the differences in trendline by area of the world (he covers the whole world by grouping ocean areas with nearby continents). GISS trend minus UAH trend, degrees C per decade:Arctic: 0.134
North America: -0.026
South America: -0.013
Europe: 0.05
Africa: 0.104
Asia: 0.077
Australia: -0.02
Antarctica: 0.139
So, the three highest differences, each about an order of magnitude higher than differences in other areas, are in 1. Antarctica; 2. Arctic; and 3. Africa. What do these three have in common?
Well, what the have most in common is the fact that these are also the three areas of the world with the poorest surface temperature coverage. Here is the GISS coverage showing color only in areas where they have a thermometer record within a 250km box:
The worst coverage is obviously in the Arctic, Antarctica and then Africa. Coincidence?
Those who want to argue that the surface temperature record should be used in preference to that of satellites need to explain why the three areas in which the two diverge the most are the three areas with the worst surface temperature data coverage. This seems to argue that flaws in the surface temperature record drive the differences between surface and satellite, and not the other way around.
Apologies to Tisdale if this is where he was going in his next post in the series.
It is actually even worse than it sounds at first glance because for areas such as the arctic and antarctic, temperatures are filled by the model projections instead of actual observation. Then these model projections are used to create global averages which are then used to produce model projections so you have a positive feedback loop.
How much of the earth’s surface is water? And of course none of it’s covered by a GISS surface station!
If we were really looking for warming, we’d be carefully measuring ocean heat content.
Anthony-
I don’t know if it was intentional, but you pasted the post out of order
Warren
Using my favorite cherry pickin’ site, it’s interesting how much GISS diverges from all the others: click
It should also be kept in mind that 89% of the surface station record is unreliable: click
Best to go with the satellite and ARGO record instead. The urge to diddle with the surface data is just too much for some folks to resist: click
And Asia isn’t that far behind in 4th.
Africa might be a good place to drill down a little farther, separating it into zones either geographically or politically. My bet is that the S. Africa difference will be a lot closer than say sub Saharan regions. Probably able to detect differences in Asian areas the same way.
Warren Meyer: You wrote, “Apologies to Tisdale if this is where he was going in his next post in the series.”
No apologies necessary. It’s not where I was going. In Part 2, I’ll be looking at GISS land surface temperatures versus TLT over the same continental land mass areas. Then I’ll be looking at OI.v2 SST data (the dataset used by GISS in GISTEMP since ~1982) versus TLT over the same ocean areas in Part 3. And as always, I’ll be illustrating the differences graphically.
Regards
Off Topic
Holy Crap – Michael Jackson is Dead!!!
It should also be kept in mind that 89% of the surface station record is unreliable
90% with the most recent stations included.
Sonicfrog (15:33:56) :
Damn, you beat me to it by almost 2 minutes (I put it in the tips section).
As it was known, Michael Jackson was breating pure oxygen regularly. He must have taken massive doses of anti-oxydants to try to repair damages to his cells from breathing pure oxygen. I hope the EPA won’t use that as a reason to tax us if we have plants at home that produce oxygen during photosynthesis… that stuff can kill you too!!! And Obama will say that it pollutes our air and water…
I know the topic is GISS vs satellite data, but something odd is happening with GISS vs HadCRUT3 too.
Like Lucia at The Blackboard, I’ve been following trends for the five databases, in my case I’m concentrating on data since Jan 2000 (the beginning of “this decade” as far as I’m concerned).
Since then, the HadCRUT3 trend based on monthly data is essentially zero. The GISS trend is about 1 deg/century.
Here’s a curiosity I noted at the Blackboard; one could treat the GISS/HadCRUT3 difference data as two separate datasets, with a breakpoint in the middle of 2004.
See my post at the Blackboard (comment#13090)
http://rankexploits.com/musings/2009/want-to-see-some-weird-trends/
(BTW, Lucia didn’t seem impressed :), and I admit the statistics here are not rock solid.)
A similar, but not quite as distinct feature can be seen for the NOAA/HadCRUT3 data (not shown).
Anyone else notice this? More importantly, anyone know of any changes that might have occured in 2004 wrt to how the data are treated by the two agencies?
coyote (14:34:22) : “Anthony-I don’t know if it was intentional, but you pasted the post out of order. –Warren”
It does seem a bit garbled in just one place. Not to mention “anamolies.”
Over the last 12 years GISS has a similar size trend to HAdcru UAH and RSS.
It just happens to be the opposite sign. Lol.
http://www.woodfortrees.org/plot/uah/from:1997.5/plot/uah/from:1997.5/trend/plot/rss/from:1997.5/plot/rss/from:1997.5/trend/plot/gistemp/from:1997.5/plot/gistemp/from:1997.5/trend/plot/hadcrut3vgl/from:1997.5/plot/hadcrut3vgl/from:1997.5/trend
So, the three highest differences, each about an order of magnitude higher than differences in other areas, are in 1. Antarctica; 2. Arctic; and 3. Africa. What do these three have in common?
Well the first two of them are regions where the MSU technique can’t be properly used, which is why RSS don’t measure there.
I wonder what they will make of the current heatwave, USA Today said record highs are being broken in half of the country, this after a series of cold snaps broke tons of cold records but USA Today had no coverage of that.
NOAA will probably use that to say they were right after record highs coming and send someone to gloat in the face of people who think the Earth is cooling, maybe they think Cap and Trade will have unprecendented support because of that. O.o
That should be “to say they were right about record highs coming…”, and I know I spelled unprecedented wrong.
Trends since 1980 in degrees per decade :
GISS: 0.159
HADCRUT: 0.159
RSS: 0.157
UAH: 0.128
Well I’m not at all surprised by the discrepancies that you two are pointing out.
I have been totally suspicious of the surface “measured” results for a long time; simply on the grounds that as far as spacial sampling goes, GISS doesn’t even come close to satisfying the Nyquist sampling theorem requirements. On top of that, the reporting of min/max temperatures daily for the land based sites also fails to conform to the needs of a proper sampling of a 24 hour function that is not time symmetric; and of course totally ignores the effect of cloud transients. The planet earth of course correctly integrates all of those frequency components, both temporal and spatial. The satellite based measurements should inherently have better sampling regimens.
The notion that a “temperature anomaly” can be legitimately used to represent points spaced as much as 1200 km apart seems to me to be totally ludicrous. The whole UHI situation indicates how silly that is.
I don’t see any point in making computer gridded models that work on a regular “grid” of 75 km or so; when no such real world grid exists for making actual data measurements to compare to the predictions of such a model.
Anyway, I await the development of this theme, that you are pursuing here.
George
Michael Hauber (17:43:53) :
Thanks. Now show us how the trends are accelerating.
Hmmm….that might be tough.
Trends since Jan 2000
GISS: 0.102
HADCRUT: .0007
RSS: 0.0002
UAH: 0.0028
(What is it with those GISS guys, anyway?
Do contrails drive the difference between surface and satellite temperature measurements? The warming trend due to contrails reported by NASA in 2004 seems to have disappeared from the discussion in recent years;
“NASA scientists have found that cirrus clouds, formed by contrails from aircraft engine exhaust, are capable of increasing average surface temperatures enough to account for a warming trend in the US that occurred between 1975 and 1994 …..”
http://earthobservatory.nasa.gov/IOTD/view.php?id=4435
Is the contrail effect still relevant in accessing warming trends or has that work at NASA been discredited?
John M,
Why is GISS higher since 2000? Look at a map of GISS for trends since 2000 with 1200km smoothing. This shows a large hot spot over the Arctic, which contributes to a warming trend.
Now create a trend map with 250km smoothing. The hot spot is largely absent, as most of it is extrpolated from stations around the edge of the Arctic. HADCRUT does not extrapolate. The satellites measurements have a hole in the Arctic as well due to their orbit. So the HADCRUT, UAH and RSS view are closer to the map with the 250km smoothing, which is missing a lot of this hot spot.
Maps of GISS trends can be created at http://data.giss.nasa.gov/gistemp/maps/
I canot show this trend accelerating since 1980, so obviously this acceleration must be smaller than the fluctuations due to noise/natrual variation etc.
If you could show me that the largest possible fluctuations due to noise/natural variation must be smaller than the acceleration expected due to CO2 since 1980 I would have consider this lack of acceleration evidence against CO2 warming at the rate predicted by IPCC.
Hansens stated estimate in 1981 was that natural variations and fluctuations could be strong enough to totally cancel out all CO2 warming for periods of up to 20 years.
RE: Phil. (17:31:27) : “Well the first two of them are regions where the MSU technique can’t be properly used, which is why RSS don’t measure there.”
It is very easy to talk past each other on this without defining terms. The The MSU technology is not useful for the last few degrees of latitude, but there is Arctic and Antarctic beyond these degrees. UAH shows a decadal trend of .44 for NoPolar and -.08 for SoPolar.
An Inquirer (21:06:33) :
It is very easy to talk past each other on this without defining terms. The The MSU technology is not useful for the last few degrees of latitude, but there is Arctic and Antarctic beyond these degrees. UAH shows a decadal trend of .44 for NoPolar and -.08 for SoPolar.
In the case of the SoPolar those ‘last few degrees’ are 15º, using data from 70ºS to 85ºS as UAH do is very dubious, likewise for Greenland and North of 82.5ºN.
I am a teacher in the Eastern Cape area of South Africa. Recently I attended a teacher workshop with teachers from the rural areas where most of the people are very poor subsistence farmers, who rely on the weather to grow their crops, as they do not have the resources to irrigate.
I asked the teachers (many of them middle-aged) if they had noticed global warming or climate change in their areas. They were unanimous: “Not at all”. They also felt that people in their areas had MUCH bigger problems to worry about.
Michael Hauber (20:53:57) :
Thanks. So if we need to wait 20 years to make sure we’re not seeing a natural variation, why are we now hearing it stated with confidence that things are much worse now than we thought even two years ago when the IPCC report came out?
Is it that 10 year trend in arctic ice or that 15 year trend in hurricane damage?
And those 20 year “masking events” seem to be pretty darn common?
Annabelle (03:29:00) That single observation is worth a 1000 climate model studies.
tallbloke (16:51:46) :
“Over the last 12 years GISS has a similar size trend to HAdcru UAH and RSS.”
What a complete different picture emerges if you extend your data to cover a period of 13.5 yrs (rather than starting at the anomalous El Nino year, as you did):
http://tinyurl.com/lvqjzj
GISS station data (http://data.giss.nasa.gov/gistemp/graphs/Fig.A.txt) are in good agreement with MSU.
But, after the extrapolation made by Hansen (http://data.giss.nasa.gov/gistemp/graphs/Fig.A4.txt) , we have a extra warming that is causing the divergence with MSU: (in 2008, by example, from +0.54ºC to +0.75ºC)
The problem isn´t the poor station coverage. The problem is in the extrapolation of the data to the zones without coverage.
In the ocean, GISS uses satellite data, being in agreement with MSU, of course.
Phil. (21:41:22) :
I have a question for you. What is the physical mechanism that causes CO2 to warm the planet?
“”” ohioholic (12:08:42) :
Phil. (21:41:22) :
I have a question for you. What is the physical mechanism that causes CO2 to warm the planet? “””
It’s really very simple.
CO2 is a rare trace gas in the atmosphere; about one in 2597 air molecules is CO2, so on average it is about 13.75 molecular layers in 3-d space between one CO2 molecule and another one; so they aren’t even aware of the other’s presence.
The earth’s surface which is mostly water, is many hundreds of times denser than the atmosphere, and the solid ground portion is on average 5-6 times denser than the water; and both of those materials emit something like 390 W/m^2 at the global mean temperature of about +15 deg C (288 K).
At that temperature, the emitted radiation has a specral peak emittance at around 10.1 microns wavelength. CO2 has a resonance vibrational absorption band at around 14.8-15 microns or so. At the surface density and temperature it is about 13.5 to 16.5 microns radiation that can be absorbed by the CO2 moelcule. The excited CO2 molecule collides with ordinary atmospheric gases of N2 and O2, nad rarely Ar, and the energy from the aborbed IR photons is redistributed and warms the atmospheric gases. The warm atmosphere in turn then radiates its own IR spectrum, which is generally at a longer wavelength, since the air temperature is cooler than the surface (Wien Displacement Law). The re-radiated energy goes in every direction, so only about half goes downwards towards the ground; the rest goes upwards towards escape to space. Because of the temperature and pressure gradients in the atmosphere, it is easier for the upward radiation to escape, than it is for the downward radiation to reach the ground. Multiple re-absorptions and re-emissions take place, with the downward path being more obstructed by more CO2 than the upward path which has less CO2.
So the portion of the downward IR re-emission that reaches the ground or ocean gets re-absorbed in the surface which replaces some of the lost energy, so the ground doesn’t cool as fast, which is akin to saying it stays warmer. In the case of the water surface, that surface IR absorption can cause prompt evaporation of water vapor into the atmosphere; which removes ahuge amount of additional thermal energy from the surface; around 545 calories per gram of water evaporated.
But CO2 is not like other gases; it is magic; and the sort of atmospheric warming that only CO2 can do, has the unique property of being able to wake up all the water vapor that is present in the atmosphere; about 25 water molecules for every CO2 molecule is typical. By themselves, water molecules which are also a green house gas, simply remain asleep and don’t do anything, until that magic moment when they are awakened by the CO2 molecule, and they immediately also start to absorb infra red radiation from the surface to add to the warming that the CO2 caused.
Now water vapor can absorb much more infrared energy than CO2 can; but only after being woken up by the CO2 molecule. That process is called “feedback”. So it is actually the water vapor that is the green house gas that causes global warming climate change; but only after it gets the go ahead from the wake up call from the CO2 molecule.
Not even Steven Hawking himslef has been able to explain why water vapor cannot warm the atmosphere by itself without the CO2 wake-up. Totally weird, that initial atmospheric warming by the ever present water molecules at around 25 times the abundance of CO2, is unable by itslef to warm the surface and do the whole job that it is able to do after being woken up.
That’s about the size of it; you could probably get yourself a Nobel Prize in Physics, if you can explain how CO2 wakes up water vapor and gets it to absorb Infrared, and warm up the atmosphere, and surface. Good luck
George
That’s about the size of it; you could probably get yourself a Nobel Prize in Physics, if you can explain how CO2 wakes up water vapor and gets it to absorb Infrared, and warm up the atmosphere, and surface. Good luck
Too late George, Clausius & Clapeyron did it over 150 years ago!