GISS vs CRU/RSS/UAH

[skierinvermont]

As you said yourself, the arctic is 6% of the surface. It has warmed 1.5C since 1995.

This has raised the global temperature change by .08C. In other words, if we removed the arctic from 1995-present, GISS would be .08C cooler today. As I said, the rapid warming of the arctic explains all or nearly all of the divergence. This is simple math. Remove the warming 66-90N on GISS, and the divergence disappears.

Here's the math representing the effect of 6% of the earth warming by 1.5C. The effect is to raise the global temperature anomaly by .08C.

.94X +.06(1.5) = .25

X = .17

.25-.17 = .08C

.25= warmign of globe including the arcitc on GISS

.17C=warming of the other 94% after removing the 6% that warmed 1.5C

.08C=the difference

(I assume for the purpose of this calculation that the globe has warmed .25C since 1995 on GISS. If you assume a smaller number, the effect is increased. If you assume a bigger number, the effect is decreased. If for example, I assume that GISS only increased .15C since 1995, the effect of 1.5C of arctic warming increases to .09C. I'm just too lazy to perform a trend analysis to arrive at the true number so I used .25C as an approximation based on the graph of GISS).

[tacoman25]

2006-2009 is 4 years. 2002 and 2003 had bigger divergences than half of them (2006 and 2008 had smaller divergences).

If I drew a trend line from 2002-present, the divergence would have only grown slightly.

Again, I have no expectation of a perfect correlation between arctic temperatures and the divergence. I don't know how you can continue to deny it's the arctic. If you remove the arctic, GISS nearly agrees with HadCRUT.

Here it is graphically represented for you. GISS clearly diverged increasingly with all other sources as the decade went on, starting in 2002. UAH and HadCRU saw virtually the same trend, while RSS saw a greater trend (trending closer to UAH). But all sources diverged further from GISS.

[tacoman25]

2006-2009 is 4 years. 2002 and 2003 had bigger divergences than half of them (2006 and 2008 had smaller divergences).

If I drew a trend line from 2002-present, the divergence would have only grown slightly.

Again, I have no expectation of a perfect correlation between arctic temperatures and the divergence. I don't know how you can continue to deny it's the arctic. If you remove the arctic, GISS nearly agrees with HadCRUT.

Not denying the Arctic hasn't played a role, just don't think it explains everything like you do, and I don't think it has warmed as much (or as broadly) as GISS shows. And not just the true Arctic, but also high latititudes in the NH in general.

[skierinvermont]

Here it is graphically represented for you. GISS clearly diverged increasingly with all other sources as the decade went on, starting in 2002. UAH and HadCRU saw virtually the same trend, while RSS saw a greater trend. But all sources diverged further from GISS.

Ok that's more than I thought - I think partially because your graph included 2010 whereas the graph I have only went through 2009.

I'm not interested in how it compares to the satellites though. ENSO has a much more profound effect on the satellites and the ENSO trend 2002-present is quite negative.

Regardless, it doesn't matter. I don't expect a perfect correlation. As the arctic has warmed, GISS has had a tendency to show larger divergences. That more than satisfies the expectation.

As you said the arctic is 6% of the earth's surface. It has warmed 1.5C since 1995. Removing that would reduce the GISS global temperature anomaly by .08C. Basic math.

[tacoman25]

As you said yourself, the arctic is 6% of the surface. It has warmed 1.5C since 1995.

This has raised the global temperature change by .08C. In other words, if we removed the arctic from 1995-present, GISS would be .08C cooler today. As I said, the rapid warming of the arctic explains all or nearly all of the divergence. This is simple math. Remove the warming 66-90N on GISS, and the divergence disappears.

Here's the math representing the effect of 6% of the earth warming by 1.5C. The effect is to raise the global temperature anomaly by .08C.

.94X +.06(1.5) = .25

X = .17

.25-.17 = .08C

.25= warmign of globe including the arcitc on GISS

.17C=warming of the other 94% after removing the 6% that warmed 1.5C

.08C=the difference

(I assume for the purpose of this calculation that the globe has warmed .25C since 1995 on GISS. If you assume a smaller number, the effect is increased. If you assume a bigger number, the effect is decreased. If for example, I assume that GISS only increased .15C since 1995, the effect of 1.5C of arctic warming increases to .09C. I'm just too lazy to perform a trend analysis to arrive at the true number so I used .25C as an approximation based on the graph of GISS).

Where do you get that 1.5C since 1995 number? MSU shows about .6 to .7C warming in the Arctic since 1995. Look at the trend line on Will's graph from the previous page.

[skierinvermont]

I'm just going to create a graph that removes the arctic influence from GISS. I will use the arctic as 6% of the earth's surface and I will use UAH trends since 1995. That should decisively settle the role the arctic has had.

[tacoman25]

Ok that's more than I thought - I think partially because your graph included 2010 whereas the graph I have only went through 2009.

I'm not interested in how it compares to the satellites though. ENSO has a much more profound effect on the satellites and the ENSO trend 2002-present is quite negative.

Regardless, it doesn't matter. I don't expect a perfect correlation. As the arctic has warmed, GISS has had a tendency to show larger divergences. That more than satisfies the expectation.

As you said the arctic is 6% of the earth's surface. It has warmed 1.5C since 1995. Removing that would reduce the GISS global temperature anomaly by .08C. Basic math.

The graph goes from Jan 2002 to Jan 2010. Basically 2002 through 2009.

In addition, I believe your 1.5C warming since 1995 is way too high. Also, since most of the Arctic is water, it doesn't explain the increasing NH land divergence with GISS.

[tacoman25]

I'm just going to create a graph that removes the arctic influence from GISS. I will use the arctic as 6% of the earth's surface and I will use UAH trends since 1995. That should decisively settle the role the arctic has had.

That would be great.

[skierinvermont]

Where do you get that 1.5C since 1995 number? MSU shows about .6 to .7C warming in the Arctic since 1995. Look at the trend line on Will's graph from the previous page.

Looks like it goes from -.5C to +.75C to me = 1.25C

[tacoman25]

Looks like it goes from -.5C to +.75C to me = 1.25C

Definitely doesn't start that low in 1995. Looks more like -.1C or -.2C. +.75C is definitely the highest point it reaches, though it seems to plateau more in the .6 to .7 range. I would say a .8C gain looks fair to me. I'll compromise and let you go with 1C, though I think that is definitely stretching it.

[skierinvermont]

Definitely doesn't start that low in 1995. Looks more like -.1C or -.2C. +.75C is definitely the highest point it reaches, though it seems to plateau more in the .6 to .7 range. I would say a .8C gain looks fair to me.

Oh I meant including the gain in 1995. I guess that would be since 1994.

[tacoman25]

Oh I meant including the gain in 1995. I guess that would be since 1994.

Looking at the graph again, it appears the main ramp up in the Arctic was in 1993 and 1994, with a slower warming in 1995. Regardless, if you start right on the graph from the line that says 1995, it's not -.5C as the starting point. More like -.25C, but then it warms the rest of the year to about -.1C by the end of 1995.

EDIT: I just looked at some other graphs, and they seem to support this as well. The anomaly was probably around -.5C or so in early 1994, but I understood we were looking at 1995 to present.

[BethesdaWX]

Except HadCRUT already leaves those areas blank. Substituting in UAH data to fill those blanks on HadCRUT would not change the anomaly. On the other hand substituting in extremely rapid warming of nearly 1C/decade since 1995 in the arctic into the HadCRUT blanks would change the anomaly.

I also reject the premise that UAH is the best source of Antarctic temperature trends, but that is a separate debate. I would be willing to use UAH to infill in the Antarctic on HadCRUT for the sake of consistency and because it is generally correct (even if it is not exactly correct). However, it would make no difference because you would be substituting blank data with no-trend data.

Also, as I've pointed out, UAH actually shows Antarctic warming of at least .1C/decade since 1995. I can perform the trend analysis on this if anybody wants to challenge that...

No No No, surface data in the antarctic is very isolated. As stated in the Peer Reviewed Journal that I linked friday, re-written in 2010, Roy Spencer, John Christy, and many others stated UAH featured maximum error potential of +/- 0.05C/decade at most. Meaning, in the Last Decade, UAH's cooling trend most likely stands over the Antarctic, as it is, at this time, the best available data we have.

Why do you Argue for GISS when we have better data available? What is it that you Like about GISS? You and I both know UAH is, most likely, a more reliable, and more accurate dataset to use, and that GISS is the only outlier! So, why are you defending the outlying dataset, when it has the worst resolution, is on its own, and is run by Jim hansen? I don't understand.

How can you say that surface data across the Antarctic is "better" UAH and its coverage? GISS & its extrapolations are what created the diversion in the first place.

UAH also uses a non-drifting spacecraft, RSS does not. The Antarctic, Via UAH, has been cooling for the past 30 years, there is no denying the fact that UAH is most likely the best available data for the Antarctic at this time.

So, why do you argue for data that is less likely to be accurate? Again, I don't understand.

[BethesdaWX]

Oh I meant including the gain in 1995. I guess that would be since 1994.

Do you know what year the AMO went warm? 1994 on the dot.

Food for thought on specific regions affected by certain drivers, sometimes its good to think less globally.

[skierinvermont]

OK here it is. All base periods are 1961-1990. The first graph is just GISS vs HadCRUT.

The second is GISS-arctic vs HadCRUT. I counted the arctic as 5% of the earth's surface area (less than the actual 6% because HadCRUT does have some arctic coverage, on the other hand it misses much of Siberia which has also warmed rapidly the last 20 years).

The third graph is GISS-arctic-antarctic again counting each as 5% of the earth's surface area.

By doing this we see that chopping off the arctic bring GISS's and HadCRUT's trend into complete agreement over the last 21 years. Chopping off the antarctic makes the relationship between the two sources even closer for individual years, but makes the GISS trend a fraction lower than HadCRUT.

I believe this conclusively demonstrates my point that the vast majority of the divergence the last 20 years is due to the rapid warming of the arctic that occurs, which HadCRUT misses but which GISS largely correctly extrapolates. The differences between 66S and 66N are trivial. If anything, HadCRUT shows slightly more warming between 66S and 66N, which is probably attributable to its use of the HadSST2 SST reconstruction, which shows more warming than GISS's HadISST1 over the last 20 years.

[skierinvermont]

No No No, surface data in the antarctic is very isolated. As stated in the Peer Reviewed Journal that I linked friday, re-written in 2010, Roy Spencer, John Christy, and many others stated UAH featured maximum error potential of +/- 0.05C/decade at most. Meaning, in the Last Decade, UAH's cooling trend most likely stands over the Antarctic, as it is, at this time, the best available data we have.

Why do you Argue for GISS when we have better data available? What is it that you Like about GISS? You and I both know UAH is, most likely, a more reliable, and more accurate dataset to use, and that GISS is the only outlier! So, why are you defending the outlying dataset, when it has the worst resolution, is on its own, and is run by Jim hansen? I don't understand.

How can you say that surface data across the Antarctic is "better" UAH and its coverage? GISS & its extrapolations are what created the diversion in the first place.

UAH also uses a non-drifting spacecraft, RSS does not. The Antarctic, Via UAH, has been cooling for the past 30 years, there is no denying the fact that UAH is most likely the best available data for the Antarctic at this time.

So, why do you argue for data that is less likely to be accurate? Again, I don't understand.

We have something like two dozen, perhaps more, research stations scattered around the Antarctic.. which is more than enough data to do an accurate surface analysis. See the recent O'Donnnell paper. O'Donnell's results are shown below.

"UAH uses a non-drifting spacecraft and RSS doesn't" Really dude? Really? How long have you been around here and you still haven't learnt this? UAH and RSS use the exact same raw MSU satellite data from the exact same set of satellites. ALL satellites drift.

UAH has larger statistical error that GISS or HadCRUT (UAH is +/-.05C/decade since 1979, GISS is +/-.04C/decade). There is also substantial disagreement about methodology. For example STAR finds far more warming than UAH based on the exact same satellite data.

The newer radiosonde methods also find more warming than UAH.

[BethesdaWX]

lol

GISS has a smaller statistical error than UAH, are you friggin kidding me dude? Thats the biggest cluster**** of BS I've ever heard, not even IPCC believes that! We know UAH has the +/- 0.05C via Dr. Spencer in your God-like take on Peer review, GISS is way off....it extrapolates BS, you and I know that at heart. Maybe GISS is better where it measures at the stations, but the extrapolations Kill GISS, thus it is On its own.

hmmm, 2 dozen stations scattered across 1,000's of miles, or a device that measures every square Inch with at most, a +/- 0.05C/decade error potential? What would I choose?

Its widely accepted that UAH is more likely to be accurate....are you arguing otherwise> Peer reviewed by Spencer, Christy, and several others indicate the error window on UAH over the antarctic is most likely a few hundreds of a degree C.

Give it up, you have no reason, and no argument, so go with GISS/surface data over UAH.

[ORH_wxman]

lol.

hmmm, 2 dozen stations scattered across 1,000's of miles, or a device that measures every square Inch with at most, a +/- 0.05C/decade error potential?

Its widely accepted that UAH is more likely to be accurate....are you arguing otherwise> Peer reviewed by Spencer, Christy, and several others indicate the error window on UAH over the antarctic is most likely a few hundreds of a degree C.

Give it up, you have no reason, and no argument, so go with GISS/surface data over UAH.

I don't think anything prior to the early 2000s is very relevant anyway in discussing the increasing divergence this past decade. Its hard to really argue that GISS extrapolating quite warm in recent years isn't the main reason for the divergence (which is what is agreed upon...that is the reason)..... yet it is not supported by satellite data.

I have a hard time blaming the difference between Hadley and GISS as well totally on blank cells in the 50-70 latitude bands...yes as you get to 65-70, its an issue, but the difference occurs before that where we have solid data. The blank cells make up the difference when taking all of the globe into account, but as stated before, Hadley was actually a bit warmer than GISS in much of the mid latitude areas....then Hadley goes cooler in the sub-polar regions and into the outer parts of them.

[BethesdaWX]

I don't think anything prior to the early 2000s is very relevant anyway in discussing the increasing divergence this past decade. Its hard to really argue that GISS extrapolating quite warm in recent years isn't the main reason for the divergence (which is what is agreed upon...that is the reason)..... yet it is not supported by satellite data.

I have a hard time blaming the difference between Hadley and GISS as well totally on blank cells in the 50-70 latitude bands...yes as you get to 65-70, its an issue, but the difference occurs before that where we have solid data. The blank cells make up the difference when taking all of the globe into account, but as stated before, Hadley was actually a bit warmer than GISS in much of the mid latitude areas....then Hadley goes cooler in the sub-polar regions and into the outer parts of them.

So you think the extrapolations at the poles make up the large difference? If Hadley runs warmer over the mid Lattitudes, which of course cover more ground than the poles, how warm could GISS possibly be extrapolating up there?

I hear GISS adjusts the oceans to sync with the land anoms? I think there has to be some error involved there if it is true, as there are no real stations widespread over the oceans regardless......Temperature anomalies over the Ocean will of course be less variable than those on land, and those more steady anoms should be part of the global avg.

This is why I'd prefer UAH over GISS/Hadley...the certainty is much greater.

IMO, It has to be absurd to Claim GISS to have a smaller window of error than UAH, it makes no sense, knowing they've diverged from everyone.

[skierinvermont]

lol

GISS has a smaller statistical error than UAH, are you friggin kidding me dude? Thats the biggest cluster**** of BS I've ever heard, not even IPCC believes that! We know UAH has the +/- 0.05C via Dr. Spencer in your God-like take on Peer review, GISS is way off....it extrapolates BS, you and I know that at heart. Maybe GISS is better where it measures at the stations, but the extrapolations Kill GISS, thus it is On its own.

hmmm, 2 dozen stations scattered across 1,000's of miles, or a device that measures every square Inch with at most, a +/- 0.05C/decade error potential? What would I choose?

Its widely accepted that UAH is more likely to be accurate....are you arguing otherwise> Peer reviewed by Spencer, Christy, and several others indicate the error window on UAH over the antarctic is most likely a few hundreds of a degree C.

Give it up, you have no reason, and no argument, so go with GISS/surface data over UAH.

The error bar on GISS since 1979 is .04C/decade. This is smaller than UAH's .05C/decade. You claim that "even the IPCC knows UAH has smaller error." This is a blatant lie. Stop lieing. I have quoted the IPCC error estimates for the different sources several times. Here is again. The error estimates are smaller for GISS than UAH.

This chart comes directly from the ipcc report. Don't claim they agree with you because they don't. I have disproved this lie nearly a half dozen times now.

Moreover, UAH's error bars for a small region of the earth are going to be much larger than its error bars for the earth as a whole.

UAH is also directly contradicted by STAR, a newer satellite analysis.

[skierinvermont]

I don't think anything prior to the early 2000s is very relevant anyway in discussing the increasing divergence this past decade. Its hard to really argue that GISS extrapolating quite warm in recent years isn't the main reason for the divergence (which is what is agreed upon...that is the reason)..... yet it is not supported by satellite data.

I have a hard time blaming the difference between Hadley and GISS as well totally on blank cells in the 50-70 latitude bands...yes as you get to 65-70, its an issue, but the difference occurs before that where we have solid data. The blank cells make up the difference when taking all of the globe into account, but as stated before, Hadley was actually a bit warmer than GISS in much of the mid latitude areas....then Hadley goes cooler in the sub-polar regions and into the outer parts of them.

Even having 20% missing at 50-60N would lower the trend from .5C/decade to .4C/decade, and introduce a divergence of .1C/decade. The actual divergence observed at 50-60N, according to the WUWT chart, was .1C/30 years, or .03C/decade. If anything, given the number of blank cells 50-60N on HadCRUT in Asia, I am surprised the divergence is not larger than .03C/decade at that latitude band.

Here is GISS without the arctic and antarctic. Perfect agreement with HadCRUT. If anything, HadCRUT is warming faster 66S to 66N.

[skierinvermont]

So you think the extrapolations at the poles make up the large difference? If Hadley runs warmer over the mid Lattitudes, which of course cover more ground than the poles, how warm could GISS possibly be extrapolating up there?

The same as UAH. The trend of the extrapolations in the arctic is approximately the same as UAH's.

GISS arctic temperatures vs UAH arctic temperatures:

[ORH_wxman]

You need to focus on the recent trend, not from the 1990s.

The polar warming (or lack there of) on UAH in the past 8-9 years does not support GISS divergence from Hadley.

[skierinvermont]

You need to focus on the recent trend, not from the 1990s.

The polar warming (or lack there of) on UAH in the past 8-9 years does not support GISS divergence from Hadley.

I am focusing on the recent trend. Arctic temperatures were the warmest in the last 8 years, and that is where my model makes the largest subtractions from GISS. Again, GISS minus the arctic and antarctic is seen below. To deny that the divergence is primarily due to the arctic after this graph doesn't make any sense. You remove the arctic, the divergence disappears, and GISS and HadCRUT agree nearly perfectly. End of story.

You are nitpicking little details, which makes little sense given the error bars on GISS for single years.

[ORH_wxman]

I am focusing on the recent trend. Arctic temperatures were the warmest in the last 8 years, and that is where my model makes the largest subtractions from GISS. Again, GISS minus the arctic and antarctic is seen below. To deny that the divergence is primarily due to the arctic after this graph doesn't make any sense. You remove the arctic, the divergence disappears, and GISS and HadCRUT agree nearly perfectly. End of story.

I'm not sure what you are arguing. Our argument (or at least mine) is that their extrapolations are wrong. Of course the divergence all due to the arctic there because they have virtually no trend in the southern polar regions (I think they are a very slight warming trend actually) and a huge warming trend in the arctic.

The argument is that other data does not support their warmer trends in each region. UAH is cooling in the southern polar regions since '02-'03 and is warming much less rapidly in the arctic.

[skierinvermont]

I'm not sure what you are arguing. Our argument (or at least mine) is that their extrapolations are wrong. Of course the divergence all due to the arctic there because they have virtually no trend in the southern polar regions (I think they are a very slight warming trend actually) and a huge warming trend in the arctic.

The argument is that other data does not support their warmer trends in each region. UAH is cooling in the southern polar regions since '02-'03 and is warming much less rapidly in the arctic.

Originally you suggested that the divergence was not due to the arctic.

So you agree that after removing the arctic and antarctic GISS agrees with HadCRUT, and therefore the divergence is due to the extrapolations in the arctic, antarctic (and also Siberia). The question then becomes, are the extrapolations correct. Good, we agree on the cause of the divergence. So now let's ask, are the extrapolations correct?

Indeed we see that they are. GISS arctic vs UAH arctic 1993-2009:

[ORH_wxman]

So you agree that after removing the arctic and antarctic GISS agrees with HadCRUT, and therefore the divergence is due to the extrapolations in the arctic, antarctic (and also Siberia). The question then becomes, are the extrapolations correct. Good, we agree on the cause of the divergence.

Indeed we see that they are. GISS arctic vs UAH arctic 1993-2009:

I don't think I ever argued otherwise...I know tacoman thought other areas played a role, but Hadley was actually warmer than GISS in the mid-latitudes. and colder once past 50 degrees toward each pole.

My argument is that GISS' extrapolations have been over exuberant on the warm side based on both some of Hadley's own data near the edges and satellites.

[nzucker]

The error bar on GISS since 1979 is .04C/decade. This is smaller than UAH's .05C/decade. You claim that "even the IPCC knows UAH has smaller error." This is a blatant lie. Stop lieing. I have quoted the IPCC error estimates for the different sources several times. Here is again. The error estimates are smaller for GISS than UAH.

This chart comes directly from the ipcc report. Don't claim they agree with you because they don't. I have disproved this lie nearly a half dozen times now. Moreover, UAH's error bars for a small region of the earth are going to be much larger than its error bars for the earth as a whole.

UAH is also directly contradicted by STAR, a newer satellite analysis.

Is it possible to find error bars for the last decade or so? Is there any more recent analysis to tell us "how the sources are doing?"

[skierinvermont]

I don't think I ever argued otherwise...I know tacoman thought other areas played a role, but Hadley was actually warmer than GISS in the mid-latitudes. and colder once past 50 degrees toward each pole.

My argument is that GISS' extrapolations have been over exuberant on the warm side based on both some of Hadley's own data near the edges and satellites.

Well I disagree on the edges. Where they both have data 50-70N, I believe they agree. It is the blank cells in Siberia artificially creating a divergence on that WUWT image.

In reality, we know these blank cells in Siberia, like the arctic, have warmed rapidly.

GISS is in general agreement with UAH on the trend in the arctic, as my graph above showed (Sorry for no labels, it's 1993-2009).

[ORH_wxman]

Well I disagree on the edges. Where they both have data 50-70N, I believe they agree. It is the blank cells in Siberia artificially creating a divergence on that WUWT image.

In reality, we know these blank cells in Siberia, like the arctic, have warmed rapidly.

GISS is in general agreement with UAH on the trend in the arctic, as my graph above showed (Sorry for no labels, it's 1993-2009).

There is almost no blank areas on Hadley through 60 degrees on each side and they are already diverged by that point by a few tenths in the arctic, and the error is much more egregious in the southern polar region by 60S. So we'll agree to disagree on that part anyway.

I think it supports GISS's warm bias in the two polar regions when put in tandem with satellite data. But regardless if we agree on that or not, there is little at the moment to support GISS's warmer extrapolations in the past decade or so.