2011 Global Temperatures

[tacoman25]

Wow, didn't expect the UAH to come in that cold so fast.

It was a very impressive drop for four months...but pretty much what I expected, given that we saw a transistion from strong Nino to strong Nina. Not down to 2008 levels yet (that should happen over the next few months), but cooler than 1999 was at this point.

[LakeEffectKing]

It was a very impressive drop for four months...but pretty much what I expected, given that we saw a transistion from strong Nino to strong Nina. Not down to 2008 levels yet (that should happen over the next few months), but cooler than 1999 was at this point.

GISS shows an impressive resilience to buck the trend of other agencies.....goes up from Dec. departures from +.40 to +.46

[skierinvermont]

GISS shows an impressive resilience to buck the trend of other agencies.....goes up from Dec. departures from +.40 to +.46

Except of course last month when GISS dropped a whopping .33C while UAH dropped a meager .09C. I guess we all forgot about that already.

Comparing GISS to the satellites is silly since there's a timelag with ENSO and even in a given month what goes on at 5,000' may not be the same as what goes on at the surface. And as far as I know, HadCRUT isn't out yet for January. So since HadCRUT isn't out we don't really have anything to compare to except reanalysis products like JRA-25 and ERA-25. FWIW JRA-25 showed the January anomaly as .01C colder than December, which is not too big a discrepancy.

[LakeEffectKing]

Except of course last month when GISS dropped a whopping .33C while UAH dropped a meager .09C. I guess we all forgot about that already.

Comparing GISS to the satellites is silly since there's a timelag with ENSO and even in a given month what goes on at 5,000' may not be the same as what goes on at the surface. And as far as I know, HadCRUT isn't out yet for January. So since HadCRUT isn't out we don't really have anything to compare to except reanalysis products like JRA-25 and ERA-25. FWIW JRA-25 showed the January anomaly as .01C colder than December, which is not too big a discrepancy.

The "silliness" is your mischaracterization of my observation as a comparison. Nonetheless, two methods of deriving a specific parameter (in this case, global temperature anomolies) are inherently going to be looked at side by side to COMPARE outputs, in order to try and UNDERSTAND BETTER, the differences and hence HYPOTHESIZE the causes to the differing outputs.

If you already KNOW the exact reasons, then you have every right to characterize everyone else's observation as silly, because that really helps good debate.

And by the way, GISS has risen 3 out of the last 4 months during which time UAH has decreased in all 4 months, RSS has decreased in 3 out of the last 4 months (with the other month going up a few hundredths....statistically insignificant), and HadCrut nearly flat up until last month....

You seem so freakin' defensive lately....good GOD!

[WeatherRusty]

The "silliness" is your mischaracterization of my observation as a comparison. Nonetheless, two methods of deriving a specific parameter (in this case, global temperature anomolies) are inherently going to be looked at side by side to COMPARE outputs, in order to try and UNDERSTAND BETTER, the differences and hence HYPOTHESIZE the causes to the differing outputs.

If you already KNOW the exact reasons, then you have every right to characterize everyone else's observation as silly, because that really helps good debate.

You seem so freakin' defensive lately....good GOD!

Except that satellites are not measuring the same region of the atmosphere as are surface observations. Surface obs are taken at 4-5 feet above the surface while satellites are measuring contributions (brightness in molecular oxygen emmission) from the entire troposphere and even the lower stratosphere, and then applying algorithms to arrive at what the lower tropospheric temperature is.

[LakeEffectKing]

Except that satellites are not measuring the same region of the atmosphere as are surface observations. Surface obs are taken at 4-5 feet above the surface while satellites are measuring contributions (brightness in molecular oxygen emmission) from the entire troposphere and even the lower stratosphere, and then applying algorithms to arrive at what the lower tropospheric temperature is.

I understand that. My point was that when we are pointing out the outputted data for a month from one of the 4 major collectors, pointing out the differences in the output for the same months (or years, decades, etc. for that matter) we stimulate discussion that leads to your exact response.....a sharing of a little knowledge....a lesson to some who may not be as "lucky" as skier to know the differences....better to teach than to (in an elitist fashion) characterize statements as "silly".....especially when he and Bethesda not so long ago had a 4 page tiff COMPARING the areal coverage wrt sats vs. land.

[BethesdaWX]

Except that satellites are not measuring the same region of the atmosphere as are surface observations. Surface obs are taken at 4-5 feet above the surface while satellites are measuring contributions (brightness in molecular oxygen emmission) from the entire troposphere and even the lower stratosphere, and then applying algorithms to arrive at what the lower tropospheric temperature is.

Satellites measure surface too, and the drop was there as well! Go to the AMSU site if you do not believe me.

[tacoman25]

Except that satellites are not measuring the same region of the atmosphere as are surface observations. Surface obs are taken at 4-5 feet above the surface while satellites are measuring contributions (brightness in molecular oxygen emmission) from the entire troposphere and even the lower stratosphere, and then applying algorithms to arrive at what the lower tropospheric temperature is.

What is interesting is that over the last 15 years or so, when we have a really warm El Nino year (1998, 2005, 2010), the satellites are pretty close overall to GISS. AGW proponents such as yourself seem fine with them then. But cooler La Nina years result in a much larger divergence between the satellites and GISS, and then many skeptics start questioning GISS more, and AGWers start doubting the satellites more.

[WeatherRusty]

What is interesting is that over the last 15 years or so, when we have a really warm El Nino year (1998, 2005, 2010), the satellites are pretty close overall to GISS. AGW proponents such as yourself seem fine with them then. But cooler La Nina years result in a much larger divergence between the satellites and GISS, and then many skeptics start questioning GISS more, and AGWers start doubting the satellites more.

None of the measures i.e. GISS, Hadley, RSS, UAH, or any other attempt at determining Earth's temperature offer a precise answer. They are an estimate and they all differ somewhat from each other. There are at least two reasons for this. First, the Earth does not have a single definable surface temperature, it has a wide range of temperatures which we average together to arrive at a mean average temperature. Second, as in any quantitative measure, the measurement techniques and analysis lack absolute precision.

It is best not to rely on a single method or measurement when faced with a situation like this. That the differing approaches in determining global temperature all give approximately the same value helps to assure us that we are honing in on the value we seek. Therefor all of these measures are valuable and needed. None of them standing alone serves us as well as their combined contribution. None of them represent perfection, they all have issues trying to measure a single quantity that doesn't actually exist except in a statistical sense.

[skierinvermont]

The "silliness" is your mischaracterization of my observation as a comparison. Nonetheless, two methods of deriving a specific parameter (in this case, global temperature anomolies) are inherently going to be looked at side by side to COMPARE outputs, in order to try and UNDERSTAND BETTER, the differences and hence HYPOTHESIZE the causes to the differing outputs.

If you already KNOW the exact reasons, then you have every right to characterize everyone else's observation as silly, because that really helps good debate.

And by the way, GISS has risen 3 out of the last 4 months during which time UAH has decreased in all 4 months, RSS has decreased in 3 out of the last 4 months (with the other month going up a few hundredths....statistically insignificant), and HadCrut nearly flat up until last month....

You seem so freakin' defensive lately....good GOD!

I am tired of all the picking on GISS.

If anything the satellites sources have had and still do have bigger issues than GISS or HadCRUT.

It really doesn't matter whether one goes up one month and another goes up.. that is not the point of these sources.

1) They measure different things so there is no expectation of exact correspondence in the short term.

2) They are imprecise the shorter the period looked at. This goes for all of the sources (GISS, UAH, Had, RSS).

If you go back 4 months then I am just going to go back a year and half and point out that UAH has actually warmed more over the last year and a half than GISS has. From June 2009 to December 2010, GISS dropped .15C, while UAH increased .17C. Clearly UAH is secretly an AGW monger!

My point by going back one month, wasn't that you should go back 4 months comparing GISS vs UAH, nor is my point by going back 1.5 years, that you should go back 2.5 years.

My point is that the data sources are not precise enough to examine for exact correspondence over a period of one month, or even 1 year, or even 5 years. We can look for reasons for the differences on such short timescales (usually it has to do with how the different sources respond to ENSO), but it's irrelevant to AGW or the accuracy of a given source.

Now if they have diverged over a period of 10-15 years, that might be something interesting. Notable divergences include:

1) The divergence between GISS and HadCRUT over the last 10-15 years (much of which is attributable to HadCRUT simply erroneously leaving out the rapid warming in the arctic). On the other hand, GISS and HadCRUT have very similar 30 and 100 year trends, so it could be a short term thing if the arctic cools down some. In my opinion, the most accurate thing to do would be to take an average of GISS and HadCRUT, perhaps leaning towards GISS because of the large area of missing rapid warming in the arctic on Had.

2) The divergence between RSS and UAH over the last 30 years. RSS shows significantly more warming and is more in line with climate model expectations.

3) The divergence between RSS and UAH and other satellite analyses such as Fu et al. and STAR (using the same MSU +AMSU satellite data). Fu et al. and STAR show significantly more warming than either RSS or UAH.

4) The divergence between RSS and UAH and radiosonde data, as well as divergence between multiple radiosonde analyses.

[BethesdaWX]

I am tired of all the picking on GISS.

If anything the satellites sources have had and still do have bigger issues than GISS or HadCRUT.

It really doesn't matter whether one goes up one month and another goes up.. that is not the point of these sources.

1) They measure different things so there is no expectation of exact correspondence in the short term.

2) They are imprecise the shorter the period looked at. This goes for all of the sources (GISS, UAH, Had, RSS).

If you go back 4 months then I am just going to go back a year and half and point out that UAH has actually warmed more over the last year and a half than GISS has. From June 2009 to December 2010, GISS dropped .15C, while UAH increased .17C. Clearly UAH is secretly an AGW monger!

My point by going back one month, wasn't that you should go back 4 months comparing GISS vs UAH, nor is my point by going back 1.5 years, that you should go back 2.5 years.

My point is that the data sources are not precise enough to examine for exact correspondence over a period of one month, or even 1 year, or even 5 years. We can look for reasons for the differences on such short timescales (usually it has to do with how the different sources respond to ENSO), but it's irrelevant to AGW or the accuracy of a given source.

Now if they have diverged over a period of 10-15 years, that might be something interesting. Notable divergences include:

1) The divergence between GISS and HadCRUT over the last 10-15 years (much of which is attributable to HadCRUT simply erroneously leaving out the rapid warming in the arctic). On the other hand, GISS and HadCRUT have very similar 30 and 100 year trends, so it could be a short term thing if the arctic cools down some. In my opinion, the most accurate thing to do would be to take an average of GISS and HadCRUT, perhaps leaning towards GISS because of the large area of missing rapid warming in the arctic on Had.

2) The divergence between RSS and UAH over the last 30 years. RSS shows significantly more warming and is more in line with climate model expectations.

3) The divergence between RSS and UAH and other satellite analyses such as Fu et al. and STAR (using the same MSU +AMSU satellite data). Fu et al. and STAR show significantly more warming than either RSS or UAH.

4) The divergence between RSS and UAH and radiosonde data, as well as divergence between multiple radiosonde analyses.

You cannot compare UAH/RSS relationship and GISS/HADCRUT relationship...because UAH/RSS are calibrated differently, and UAH meausres more data than RSS. GISS/HADCRUT measure surface data, and HADCRUT has more data In the Arctic, and everywhere, than GISS does! Satellites agree with HADCRUT......not GISS! GISS is the warm outlier.

We don't defend a datasource that is the OUTLIER over the past decade, has the LEAST amount of data, and is TOO WARM in the arctic compared to both Satellites and HADCRUT. You bring up crackpot theories on how satellites have potential errors that we cannot correct for...because we have NO counter-verification! Hansen data should be banned from the Climate Change forum, it is just so laughable.

We pick on GISS because its complete and utter sh*t, satellite data beats GISS and its extrapolations by a country mile. GISS in inaccurate because

-GISS has the least amount of data

-Satellites and HADCRUT align...GISS is an outlier since the mid 90's

-GISS does the largest extraolations, 1,000's of miles in some cases

-GISS has been the biggest outlier of every dataset!

No One gives a sh*t if UAH/RSS disagree, because UAH measures more than RSS, and they are calibrated differently. Regardless, GISS and HADCRUT have been worse over the past 12 yrs than UAH/RSS....and thats saying something!

Satellite data is better in coverage, accuracy, and resolution than GISS and HADCRUT. We really don't need GISS/HADCRUT anyway.

Its simple sh*t.

[tacoman25]

My point is that the data sources are not precise enough to examine for exact correspondence over a period of one month, or even 1 year, or even 5 years. We can look for reasons for the differences on such short timescales (usually it has to do with how the different sources respond to ENSO), but it's irrelevant to AGW or the accuracy of a given source.

Now if they have diverged over a period of 10-15 years, that might be something interesting. Notable divergences include:

1) The divergence between GISS and HadCRUT over the last 10-15 years (much of which is attributable to HadCRUT simply erroneously leaving out the rapid warming in the arctic). On the other hand, GISS and HadCRUT have very similar 30 and 100 year trends, so it could be a short term thing if the arctic cools down some. In my opinion, the most accurate thing to do would be to take an average of GISS and HadCRUT, perhaps leaning towards GISS because of the large area of missing rapid warming in the arctic on Had.

2) The divergence between RSS and UAH over the last 30 years. RSS shows significantly more warming and is more in line with climate model expectations.

3) The divergence between RSS and UAH and other satellite analyses such as Fu et al. and STAR (using the same MSU +AMSU satellite data). Fu et al. and STAR show significantly more warming than either RSS or UAH.

4) The divergence between RSS and UAH and radiosonde data, as well as divergence between multiple radiosonde analyses.

2) You have yet to explain how .02C/decade over 30 years is a significant divergence, especially when the two sources are consistently close year after year. And if this is signficant, what about the divergence from IPCC temp projections?

3) We were discussing this the other day, remember? It does not appear that Fu was going by the same data the satellites are using today.

4) You neglect to mention GISS consistently running warmer than other sources over huge areas with sparse data in recent years (Africa, South America, Eastern Russia/Siberia, the Arctic, etc). This makes a very significant difference some months.

[skierinvermont]

You cannot compare UAH/RSS relationship and GISS/HADCRUT relationship...because UAH/RSS are calibrated differently, and UAH meausres more data than RSS. GISS/HADCRUT measure surface data, and HADCRUT has more data In the Arctic, and everywhere, than GISS does! Satellites agree with HADCRUT......not GISS! GISS is the warm outlier.

We don't defend a datasource that is the OUTLIER over the past decade, has the LEAST amount of data, and is TOO WARM in the arctic compared to both Satellites and HADCRUT. You bring up crackpot theories on how satellites have potential errors that we cannot correct for...because we have NO counter-verification! Hansen data should be banned from the Climate Change forum, it is just so laughable.

We pick on GISS because its complete and utter sh*t, satellite data beats GISS and its extrapolations by a country mile. GISS in inaccurate because

-GISS has the least amount of data

-Satellites and HADCRUT align...GISS is an outlier since the mid 90's

-GISS does the largest extraolations, 1,000's of miles in some cases

-GISS has been the biggest outlier of every dataset!

No One gives a sh*t if UAH/RSS disagree, because UAH measures more than RSS, and they are calibrated differently. Regardless, GISS and HADCRUT have been worse over the past 12 yrs than UAH/RSS....and thats saying something!

Satellite data is better in coverage, accuracy, and resolution than GISS and HADCRUT. We really don't need GISS/HADCRUT anyway.

Its simple sh*t.

The satelites and HadCRUT do not align. Over the areas covered by BOTH UAH and HadCRUT, HadCRUT shows much more warming than UAH. UAH just covers more of the arctic, which makes it appear as if it agrees with HadCRUT.

In fact, RSS and UAH don't even agree with each other. UAH has .14C/decade since 1979, but RSS has .16C/decade, and this is despite the fact that UAH includes the arctic and RSS doesn't. Over the areas covered by both, the discrepancy is even larger. In addition, other superior analyses of satellite data such as STAR, Vinnikov et al. 2005, and Fu et al. 2004 show even more warming than RSS or UAH.

The primary difference between HadCRUT and GISS is that HadCRUT shows most of the arctic as blank, even though we know there has been rapid warming there from multiple other data sources (including UAH).

[BethesdaWX]

The satelites and HadCRUT do not align. Over the areas covered by BOTH UAH and HadCRUT, HadCRUT shows much more warming than UAH. UAH just covers more of the arctic, which makes it appear as if it agrees with HadCRUT.

In fact, RSS and UAH don't even agree with each other. UAH has .14C/decade since 1979, but RSS has .16C/decade, and this is despite the fact that UAH includes the arctic and RSS doesn't. Over the areas covered by both, the discrepancy is even larger. In addition, other superior analyses of satellite data such as STAR, Vinnikov et al. 2005, and Fu et al. 2004 show even more warming than RSS or UAH.

The primary difference between HadCRUT and GISS is that HadCRUT shows most of the arctic as blank, even though we know there has been rapid warming there from multiple other data sources (including UAH).

GISS has NO Data in the Arctic, Satellites and HADCRUT match better in the Arctic than the Outlier GISS! GISS being too warm is verified by satellite data....Strike 1

Dude, RSS and UAH are calibrated differently, and UAH measured more than RSS....you can't compare them. GISS has No Data in the Arctic, and HADCRUT matches the satellites better than GISS....because it Has Data. Strike 2

GISS is the only real outlier lately. The reason why RSS/UAH differ is due to their different calibrations....HADCRUT/GISS disagree because one source has alot less data, and large extrapolations. Strike 3, yer out

Again we don't defend outliers. There has been no "trend" on satellites...we've seen the "step" up that can be expected with the changes in the Oceans.

[skierinvermont]

2) You have yet to explain how .02C/decade over 30 years is a significant divergence, especially when the two sources are consistently close year after year. And if this is signficant, what about the divergence from IPCC temp projections?

3) We were discussing this the other day, remember? It does not appear that Fu was going by the same data the satellites are using today.

4) You neglect to mention GISS consistently running warmer than other sources over huge areas with sparse data in recent years (Africa, South America, Eastern Russia/Siberia, the Arctic, etc). This makes a very significant difference some months.

2) The divergence between RSS and UAH is the largest divergence between any of the 4 major temp sources over the last 30 years. If people are going to go around claiming GISS is an outlier, I am going to go around claiming UAH is an even bigger outlier.. which it is. A difference between temperature measuring sources which are intended to have a high degree of precision over the long run is much more significant than a short-term deviation from IPCC predicted values which are not intended to be precise given there is a significant level of uncertainty recognized. The IPCC interval is 2-5C.. I would hope we can measure temperature with more accuracy than we can predict it.

3) What do you mean? I don't remember this at all. He developed a methodology for calculating LT temps from the MSU channels in a way that is still not used by either UAH or RSS.

4) The Africa and S. America differences may be problematic for GISS, but it undoubtedly is superior to HadCRUT in Siberia and the arctic where temperatures have warmed rapidly but HadCRUT leaves it data blank.

[tacoman25]

The satelites and HadCRUT do not align. Over the areas covered by BOTH UAH and HadCRUT, HadCRUT shows much more warming than UAH. UAH just covers more of the arctic, which makes it appear as if it agrees with HadCRUT.

In fact, RSS and UAH don't even agree with each other. UAH has .14C/decade since 1979, but RSS has .16C/decade, and this is despite the fact that UAH includes the arctic and RSS doesn't. Over the areas covered by both, the discrepancy is even larger. In addition, other superior analyses of satellite data such as STAR, Vinnikov et al. 2005, and Fu et al. 2004 show even more warming than RSS or UAH.

The primary difference between HadCRUT and GISS is that HadCRUT shows most of the arctic as blank, even though we know there has been rapid warming there from multiple other data sources (including UAH).

What makes these other analyses superior?

[skierinvermont]

GISS has NO Data in the Arctic, Satellites and HADCRUT match better in the Arctic than the Outlier GISS! GISS being too warm is verified by satellite data....Strike 1

Dude, RSS and UAH are calibrated differently, and UAH measured more than RSS....you can't compare them. GISS has No Data in the Arctic, and HADCRUT matches the satellites better than GISS....because it Has Data. Strike 2

GISS is the only real outlier lately. The reason why RSS/UAH differ is due to their different calibrations....HADCRUT/GISS disagree because one source has alot less data, and large extrapolations. Strike 3, yer out

Again we don't defend outliers. There has been no "trend" on satellites...we've seen the "step" up that can be expected with the changes in the Oceans.

UAH is the largest outlier of the 4 data sources. This is a plain and simple fact. The 30-yr trend on UAH is farther from the other three than any of the others.

Moreover, more recent analysis of the satellite data and radiosonde data indicates that even RSS is too cold. See Fu et al. 2004, Vinnikov et al. 2005, Thorne et al. 2010.

GISS doesn't need to have tons of stations in the arctic - we know that its extrapolations are fairly correct in the long run (they run slightly too high). Even UAH shows arctic warming of 1.5C since 1990. But HadCRUT assumes that no warming has occurred in the arctic at all because it leaves the arctic blank. This is clearly and empirically demonstrated to be a FALSE assumption.

[BethesdaWX]

2) The divergence between RSS and UAH is the largest divergence between any of the 4 major temp sources over the last 30 years. If people are going to go around claiming GISS is an outlier, I am going to go around claiming UAH is an even bigger outlier.. which it is. A difference between temperature measuring sources which are intended to have a high degree of precision over the long run is much more significant than a short-term deviation from IPCC predicted values which are not intended to be precise given there is a significant level of uncertainty recognized. The IPCC interval is 2-5C.. I would hope we can measure temperature with more accuracy than we can predict it.

3) What do you mean? I don't remember this at all. He developed a methodology for calculating LT temps from the MSU channels in a way that is still not used by either UAH or RSS.

4) The Africa and S. America differences may be problematic for GISS, but it undoubtedly is superior to HadCRUT in Siberia and the arctic where temperatures have warmed rapidly but HadCRUT leaves it data blank.

Why the frigg do you keep comparing UAH to RSS? Again, their different calibrations make it illogical. GISS is really the only outlier since 1996.

[nzucker]

4) The Africa and S. America differences may be problematic for GISS, but it undoubtedly is superior to HadCRUT in Siberia and the arctic where temperatures have warmed rapidly but HadCRUT leaves it data blank.

GISS clearly extrapolates incorrectly in the Arctic, causing it to be warmer than the other sources. The problem with low-resolution extrapolations is that small areas of cold anomalies in a generally above average temperature region are going to be missed. Your point that extrapolation creates equal bias towards warmth and cold would only be true if the stations around the world were equidistant, with all areas of the globe being extrapolated to some degree. But this is not the case....most of the extrapolation comes in the High Arctic, which has generally been warm but has some pockets of colder temperatures, and GISS routinely misses this because of its low resolution. Here is an example from Jan 2011.

GISS shows all of the Yukon way above average:

The satellite data for January, with its higher resolution and no extrapolation, shows the pocket of cold anomalies in NW Canada:

GISS has made this mistake several times, and should be cross-checking with satellites in extrapolated areas to ensure it's not missing smaller pockets of cold/warm anomalies due to low resolution (huge distances between stations). This is why I am very skeptical of GISS; it just doesn't seem necessary to do extrapolations when you have data for almost the entire globe from UAH. Additionally, you keep making the point that the satellites are missing the warmth in the Arctic, but in that case they're also missing the cold anomalies in Central Antarctica which would mitigate some of the warmth in the higher latitudes of the NH.

[tacoman25]

2) The divergence between RSS and UAH is the largest divergence between any of the 4 major temp sources over the last 30 years. If people are going to go around claiming GISS is an outlier, I am going to go around claiming UAH is an even bigger outlier.. which it is. A difference between temperature measuring sources which are intended to have a high degree of precision over the long run is much more significant than a short-term deviation from IPCC predicted values which are not intended to be precise given there is a significant level of uncertainty recognized. The IPCC interval is 2-5C.. I would hope we can measure temperature with more accuracy than we can predict it.

3) What do you mean? I don't remember this at all. He developed a methodology for calculating LT temps from the MSU channels in a way that is still not used by either UAH or RSS.

4) The Africa and S. America differences may be problematic for GISS, but it undoubtedly is superior to HadCRUT in Siberia and the arctic where temperatures have warmed rapidly but HadCRUT leaves it data blank.

2) People claim GISS is the outlier for the past decade or so because it is. That's fact. You can rationalize it however you want, but it's not wrong of people to point that out. Now, if you want to argue that the UAH/RSS difference is more significant, fine...but consider this: is there any other comparable period where one data source clearly diverged from other sources as much as GISS has the past ten years?

Also, if you take 1979 (just the initial year of the satellite record, which happened to have an unusual divergence between UAH and RSS) out of the equation, I think you will be surprised at the difference that makes.

3) Go back and re-read our conversation. His analysis appeared to be made before the "upgrade" that significantly upped the trend for the satellites. Also, it was before the current satellite data that UAH uses, since those satellites were not launched at the time of his paper.

4) How do you know GISS is "undoubtedly superior" in these regions? I made a detailed post one time on the old forum comparing RSS surface analysis to GISS in these regions, and GISS consistently was warmer or had the warmer anomalies over a larger area. So it's not just HadCRUT that disagrees with GISS.

[BethesdaWX]

UAH is the largest outlier of the 4 data sources. This is a plain and simple fact. The 30-yr trend on UAH is farther from the other three than any of the others.

Moreover, more recent analysis of the satellite data and radiosonde data indicates that even RSS is too cold. See Fu et al. 2004, Vinnikov et al. 2005, Thorne et al. 2010.

GISS doesn't need to have tons of stations in the arctic - we know that its extrapolations are fairly correct in the long run. Even UAH shows arctic warming of 1.5C since 1990. But HadCRUT assumes that no warming has occurred in the arctic at all because it leaves the arctic blank. This is clearly and empirically demonstrated to be a FALSE assumption.

No, GISS is the largest outlier in the past decade. UAH has the most data, and the best resolution of all Datasources.....GISS has the worst in both camps. Usually, the more data, the cooler the anoms end up being!

We cannot claim error in Satellite data where there is NO COUNTER VERIFICATION! What don;t you understand about that? You bring up crackpot theories trying to claim satellites as false...yet you Support GISS?! What the friggin f**kbomb! If we knew that the claims of error were sound.... they would have been corrected by now. The claims are unsubstantiated craploads.

GISS and its extrapolations are why it is the largest outlier....GISS has the least amount of data, and NO arctic data. Thus, it is the warmest outlier

[tacoman25]

GISS clearly extrapolates incorrectly in the Arctic, causing it to be warmer than the other sources. The problem with low-resolution extrapolations is that small areas of cold anomalies in a generally above average temperature region are going to be missed. Your point that extrapolation creates equal bias towards warmth and cold would only be true if the stations around the world were equidistant, with all areas of the globe being extrapolated to some degree. But this is not the case....most of the extrapolation comes in the High Arctic, which has generally been warm but has some pockets of colder temperatures, and GISS routinely misses this because of its low resolution. Here is an example from Jan 2011.

GISS shows all of the Yukon way above average:

The satellite data for January, with its higher resolution and no extrapolation, shows the pocket of cold anomalies in NW Canada:

GISS has made this mistake several times, and should be cross-checking with satellites in extrapolated areas to ensure it's not missing smaller pockets of cold/warm anomalies due to low resolution (huge distances between stations). This is why I am very skeptical of GISS; it just doesn't seem necessary to do extrapolations when you have data for almost the entire globe from UAH. Additionally, you keep making the point that the satellites are missing the warmth in the Arctic, but in that case they're also missing the cold anomalies in Central Antarctica which would mitigate some of the warmth in the higher latitudes of the NH.

Just to add, look at NE Europe as well. Nothing but warmth with GISS...

[ORH_wxman]

HadCRUT actually has better arctic coverage than GISS, but just doesn't extrapolate into void data regions once far enough north. But in the areas where CRU had data in the arctic, they have run cooler than GISS.

There was a long drawn out WUWT post on this a few years ago that gathered a lot of discussion. So essentially what GISS does is take their already warmer temps in areas where both data sources have coverage, and then just paints it warm over the void region.

The Africa issue was also a big discrepancy between the two data sets in recent years when they started diverging quite a bit.

[tacoman25]

UAH is the largest outlier of the 4 data sources. This is a plain and simple fact. The 30-yr trend on UAH is farther from the other three than any of the others.

Moreover, more recent analysis of the satellite data and radiosonde data indicates that even RSS is too cold. See Fu et al. 2004, Vinnikov et al. 2005, Thorne et al. 2010.

GISS doesn't need to have tons of stations in the arctic - we know that its extrapolations are fairly correct in the long run (they run slightly too high). Even UAH shows arctic warming of 1.5C since 1990. But HadCRUT assumes that no warming has occurred in the arctic at all because it leaves the arctic blank. This is clearly and empirically demonstrated to be a FALSE assumption.

And what about the Antarctic, where large parts of the interior have cooled?

[skierinvermont]

GISS clearly extrapolates incorrectly in the Arctic, causing it to be warmer than the other sources. The problem with low-resolution extrapolations is that small areas of cold anomalies in a generally above average temperature region are going to be missed. Your point that extrapolation creates equal bias towards warmth and cold would only be true if the stations around the world were equidistant, with all areas of the globe being extrapolated to some degree. But this is not the case....most of the extrapolation comes in the High Arctic, which has generally been warm but has some pockets of colder temperatures, and GISS routinely misses this because of its low resolution. Here is an example from Jan 2011.

GISS shows all of the Yukon way above average:

The satellite data for January, with its higher resolution and no extrapolation, shows the pocket of cold anomalies in NW Canada:

GISS has made this mistake several times, and should be cross-checking with satellites in extrapolated areas to ensure it's not missing smaller pockets of cold/warm anomalies due to low resolution (huge distances between stations). This is why I am very skeptical of GISS; it just doesn't seem necessary to do extrapolations when you have data for almost the entire globe from UAH. Additionally, you keep making the point that the satellites are missing the warmth in the Arctic, but in that case they're also missing the cold anomalies in Central Antarctica which would mitigate some of the warmth in the higher latitudes of the NH.

You are wrong about stations having to be equidistant. PLEASE stop and think about this. I know you are smarter than this. If a cold bubble happens to fall on a GISS station, GISS will falsely extrapolate that cold for 500+ miles. This is why it balances out. Moreover... GISS's arctic extrapolations are confirmed by multiple other agencies that show essentially the same overall arctic trend (GISS is slightly too high but much better than the Had null assumption of zero warming).

Cross checking with satellites completely defeats the purpose of GISS as an indpeendent measure of SURFACE temperature. I have explained this to you before. Moreover, you are just simply wrong about the extrapolations.

[BethesdaWX]

HadCRUT actually has better arctic coverage than GISS, but just doesn't extrapolate into void data regions once far enough north. But in the areas where CRU had data in the arctic, they have run cooler than GISS.

There was a long drawn out WUWT post on this a few years ago that gathered a lot of discussion. So essentially what GISS does is take their already warmer temps in areas where both data sources have coverage, and then just paints it warm over the void region.

The Africa issue was also a big discrepancy between the two data sets in recent years when they started diverging quite a bit.

Usually the warmest areas on GISS actually have no measured data.

If we hadn't deleted so many stations, GISS wouldn't have had the problems it does now.

This is absolutely ridiculous and pathetic......GISS could easily get more data. Shows complete ignorance.

[BethesdaWX]

And what about the Antarctic, where large parts of the interior have cooled?

UAH has the Antarctic cooling for the past 30yrs...GISS shows warming. Who should we believe?

I'd take UAH and its measured data over extrapoltations anyday!

Obvious whats going on here...

[tacoman25]

You are wrong about stations having to be equidistant. PLEASE stop and think about this. I know you are smarter than this. If a cold bubble happens to fall on a GISS station, GISS will falsely extrapolate that cold for 500+ miles. This is why it balances out. Moreover... GISS's arctic extrapolations are confirmed by multiple other agencies that show essentially the same overall arctic trend (GISS is slightly too high but much better than the Had null assumption of zero warming).

Cross checking with satellites completely defeats the purpose of GISS as an indpeendent measure of SURFACE temperature. I have explained this to you before. Moreover, you are just simply wrong about the extrapolations.

In a perfect world...

It just doesn't seem to balance out when GISS consistently has more areas warmer (often extrapolated regions) than other sources. If the satellite data and the surface data agree on 90% of the area of a map, what makes you think that places where they disagree and GISS is warmer, that automatically doesn't mean anything because they are technically measuring something different?

Also, suppose you are right, and the odds are 50/50 that GISS will extrapolate 500 miles cold or warm...except that more of GISS's extrapolating stations just happen to be in locations that are exceptionally warm. Due to the inherent innaccurracy of extrapolation, the only way it could guarantee to be balanced is if extrapolating regions were guaranteed not to be overrepresented by warm (relative to the rest of the globe) stations.

[ORH_wxman]

In a perfect world...

It just doesn't seem to balance out when GISS consistently has more areas warmer (often extrapolated regions) than other sources. If the satellite data and the surface data agree on 90% of the area of a map, what makes you think that places where they disagree and GISS is warmer, that automatically doesn't mean anything because they are technically measuring something different?

Also, suppose you are right, and the odds are 50/50 that GISS will extrapolate 500 miles cold or warm...except that more of GISS's extrapolating stations just happen to be in locations that are exceptionally warm. Due to the inherent innaccurracy of extrapolation, the only way it could guarantee to be balanced is if extrapolating regions were guaranteed not to be overrepresented by warm (relative to the rest of the globe) stations.

This was the big discrepancy of the debate a few years ago when GISS was compared to other data sources. They were consistently warmer in the questioned regions than satellite and known HadCRUT data. Arctic gets talked about a lot, but Africa was a big one and so was Antarctica. There's a reason that the CRU group thinks GISS is too warm even though they are big proponents of AGW.

[nzucker]

Just to add, look at NE Europe as well. Nothing but warmth with GISS...

Yes, GISS clearly missed the area of cold anomalies...they falsely added warmth in Scandinavia and to the south, looks very suspicious.

You are wrong about stations having to be equidistant. PLEASE stop and think about this. I know you are smarter than this. If a cold bubble happens to fall on a GISS station, GISS will falsely extrapolate that cold for 500+ miles. This is why it balances out. Moreover... GISS's arctic extrapolations are confirmed by multiple other agencies that show essentially the same overall arctic trend (GISS is slightly too high but much better than the Had null assumption of zero warming).

Cross checking with satellites completely defeats the purpose of GISS as an indpeendent measure of SURFACE temperature. I have explained this to you before. Moreover, you are just simply wrong about the extrapolations.

But they don't ever extrapolate the cold for hundreds of miles...we've looked at these maps, GISS vs RSS, several times...and the extrapolations always tend to be on the warm side. Can't you just admit looking at that map that mistakes are being made? How much clearer can it be when GISS is extrapolating pure warmth when higher-resolution satellites are finding small areas of cold anomalies in a generally mild region? December 2010 and January 2011 have had the same problem. Also, stations closer to the coast and with developed settlements, which is most of them, are going to run a bit milder than other areas of the rural High Arctic, no way around it. The problem with using GISS for the arctic is that the sea of warmth makes it hard for extrapolated data to pick up on the smaller areas of cold; it's an inevitable mistake but probably an intentional one given that Hansen is running the data set, a man who has been arrested for protesting fossil fuels.

If GISS is making bad extrapolations, then it should be checked. Just following the models throughout December, I knew there was a small area of cold anomalies in the Yukon just because I repeatedly saw the -20C contour over the high pressure centered in NW Canada during the month. RSS satellite analysis confirmed my suspicion that it had been a frigid December in parts of the Yukon, but GISS just missed it...doesn't make any sense that someone casually following the weather can have a better understanding of climate trends than NASA. Also, widespread media reports were talking about near-record cold in Scandinavia during December, and yet GISS only had the region 1-2C below normal, seemed suspicious. I don't see the problem with cross-checking.