GISS vs CRU/RSS/UAH

[tacoman25]

Well tomorrow I'll try removing the antarctic for UAH.. I still think it does a decent job but it's pretty hard to tell the way we're doing it.

The strong divergence UAH/RSS 1980-1995 and then subsequent moderate convergence is quite interesting to me.. surprised we don't see more about this.

night

Well again, the timing of it suggest that it is probably related to AMO/PDO phases, considering both sources don't cover the same area.

I think it's also worth noting that UAH's trend has been more consistent than RSS overall.

[tacoman25]

Yeah and the ENSO trend is real negative since 02.. which leads to an upwards adjustment in my model. The model's based on regular GISS, and in retrospect I agree GISS's trends this decade are biased a little high. I would prefer an average of GISS/HAD + UAH poles for this decade. Or a straight up average of GISS/HAD (it makes very little difference this decade whether we replace the poles with UAH or not).

I just like using the Wood For Trees Index, since it combines all 4 major sources, leaving no room for bias and including the most data (since we really don't know for sure whose is best).

[skierinvermont]

Can anyone give me exact numbers or a good estimate for what percent of the earth's surface area is between 60S-70S and then for 60S-90S?

I think you need integrals to do it and I've forgotten how to go about doing that. And I can't find anything online that will do it for me.

I'm just going to go with 3% and 7.5% respectively unless someone can give me some more exact numbers.

Also, does UAH go to 85N or 90N? I know RSS is 82.5N.

Here are the preliminary results anyways adjusting for the antarctic using 3% for 60-70S and 7.5% for 60-90S. Trenlines are shown for all three.. the UAH and RSS trends diverge, but RSS w/ UAH antarctic overlaps with UAH so you can't see it. In other words, infilling the antarctic on RSS w/ UAH eliminates the long term divergence. There are still some differences however.

[tacoman25]

You can clearly see from the above graph that there IS a divergence this decade. We agree on this fact.. let's move on to the implications of it.

My argument is that the divergence 2000-present between them is just due to the shortness of the period being examined. When we look at longer periods, the divergence disappears and UAH infilling of the poles corroborates GISS.

Bump for skiier.

[skierinvermont]

But since the early 2000s, it does. You already acknowledged this in the other thread. And that is the point where GISS began to diverge.

The monthly comparisons from GISS to UAH are not silly. You can prove they are if you find months where GISS extrapolates much colder than UAH (which should happen just as often, according to you). I haven't seen any months like that, which is why GISS continues to run considerably warmer than UAH.

It still explains half the divergence even since the early 2000s. The remaining small divergence is much smaller than how much warmer HadCRUT diverged from GISS in the 1990s. It's simply compensating in the other direction... it's just luck and is of no concern.

The monthly visual spatial comparisons ARE completely silly. You would get laughed out by any real scientists familiar with the data sources for pointing out areas where GISS was warmer than UAH in a single month. There are plenty of areas where GISS does extrapolate colder than UAH. The reason for the divergence between UAH and GISS has nothing to do with the extrapolations. The raw station data used by GISS has warmed more than the raw data used by UAH. It has absolutely nothing to do with the extrapolations. The whole argument is just preposterous. Extrapolation doesn't lead to a warm bias. The actual temperature station data runs warmer. Honestly, I am appalled that so many of you can't grasp such basic math.

[tacoman25]

It still explains half the divergence even since the early 2000s. The remaining small divergence is much smaller than how much warmer HadCRUT diverged from GISS in the 1990s. It's simply compensating in the other direction... it's just luck and is of no concern.

The monthly visual spatial comparisons ARE completely silly. You would get laughed out by any real scientists familiar with the data sources for pointing out areas where GISS was warmer than UAH in a single month. There are plenty of areas where GISS does extrapolate colder than UAH. The reason for the divergence between UAH and GISS has nothing to do with the extrapolations. The raw station data used by GISS has warmed more than the raw data used by UAH. It has absolutely nothing to do with the extrapolations. The whole argument is just preposterous. Extrapolation doesn't lead to a warm bias. The actual temperature station data runs warmer. Honestly, I am appalled that so many of you can't grasp such basic math.

Why is it so hard for you to grasp that GISS extrapolations in certain, low data areas (the Arctic, Africa, parts of Asia) is the most likely explanation for the divergence seen over the past 8-10 years? There are areas where GISS extrapolations consistently run warmer than other data. Please point to me the places where GISS data consistenetly runs colder than other sources. If that were the case, then there would not have been the growing divergence (especially since 2005) between GISS and the other global temp sources.

[BethesdaWX]

Sometimes I wonder if the +AMO has affected GISS somehow due to its extrapolations over the Arctic, since the +AMO really kicked in this decade. Still, GISS'sproblems are easy to asses. If its simply the +AMO, we should see GISS cool down by 2015-2020. If it continues, it means extrapolations are getting warmer... and thats suspicious.

Potential Problems with GISS:

(-)...Extrapolations, especially over the Arctic/Antarctic, but in other places too, have run warmer than other systems. Its not debatable really, just compare datasets to find out.

(-)...Terrible resolution, really makes extrapolating harder, and more error prone. And in with the Earth in a Warm period for now, more "red" (warmth) anomalies, with a low resolution dataset, will extrapolate more Red, and less Blue.

(-)...Potential Bias from Hansen, not gonna go there though.

Really though, we have better surface datasets to use rather then GISS, such as NCDC, or HADCRUT with UAH infilling on both poles. For the LT (a more accurate reading of the Greater Atmosphere), UAH/RSS are very good there, but cannot really be compared to surface datasets

[tacoman25]

Sometimes I wonder if the +AMO has affected GISS somehow due to its extrapolations over the Arctic, since the +AMO really kicked in this decade. Still, GISS'sproblems are easy to asses. If its simply the +AMO, we should see GISS cool down by 2015-2020. If it continues, it means extrapolations are getting warmer... and thats suspicious.

Potential Problems with GISS:

(-)...Extrapolations, especially over the Arctic/Antarctic, but in other places too, have run warmer than other systems. Its not debatable really, just compare datasets to find out.

(-)...Terrible resolution, really makes extrapolating harder, and more error prone. And in with the Earth in a Warm period for now, more "red" (warmth) anomalies, with a low resolution dataset, will extrapolate more Red, and less Blue.

(-)...Potential Bias from Hansen, not gonna go there though.

Really though, we have better surface datasets to use rather then GISS, such as NCDC, or HADCRUT with UAH infilling on both poles. For the LT (a more accurate reading of the Greater Atmosphere), UAH/RSS are very good there, but cannot really be compared to surface datasets

How does NCDC with UAH poles compare to HadCRU with UAH poles?

[BethesdaWX]

How does NCDC with UAH poles compare to HadCRU with UAH poles?

HADCRUT with UAH Poles is a bit cooler than NCDC with poles, but NCDC has lower resolution outside the USA, while HADCRUT has the highest resolution overall globally, but a bit lower resolution in the USA. HADCRUT is the first choice for most regardling Global Temperatures, including the IPCC.

HADCRUT globally without UAH polar infilling:

The Globe outside the poles has been Cooling for almost a decade and a half when using the higher reso model. UAH Arctic however has 0.8C of warming since 1979, the Antarctic has cooled 0.5C since 1979. Of course Arctic trends will be stronger than Antarctic Trends since the Arctic is surrounded by huge NH land masses, while the antarctic is surrounded by Ocean.

[tacoman25]

Something I've noticed when comparing GISS maps to AMSU satellite maps is that they almost always agree pretty well in North America, and especially the U.S. This suggests to me that in places with little extrapolation, GISS agrees well with satellite data. It's always sparsely populated places with more extrapolation where AMSU/GISS seem to disagree.

[nzucker]

Something I've noticed when comparing GISS maps to AMSU satellite maps is that they almost always agree pretty well in North America, and especially the U.S. This suggests to me that in places with little extrapolation, GISS agrees well with satellite data. It's always sparsely populated places with more extrapolation where AMSU/GISS seem to disagree.

Of course it is...it's easy to fudge the data for Northern Siberia's temperatures than NYC's.

[skierinvermont]

Why is it so hard for you to grasp that GISS extrapolations in certain, low data areas (the Arctic, Africa, parts of Asia) is the most likely explanation for the divergence seen over the past 8-10 years? There are areas where GISS extrapolations consistently run warmer than other data. Please point to me the places where GISS data consistenetly runs colder than other sources. If that were the case, then there would not have been the growing divergence (especially since 2005) between GISS and the other global temp sources.

The extraps obviously ARE the reason for the divergence, but that doesn't mean the extraps are wrong. In fact, we know they're right, since when we infill HadCRUT with UAH we get the same result as GISS with only minor differences over the last 30 years.

HadCRUT runs warmer than UAH between 60N and 60S and HadCRUT has very small extrapolation. The raw station data at the surface shows more warming than the satellites. The actual raw surface stations show more warming than the satellites do. This is why the surface data sources show more warming... not the extrapolations. Either the surface has actually warmed more, or more likely, the satellite data is biased cold.

[skierinvermont]

Of course it is...it's easy to fudge the data for Northern Siberia's temperatures than NYC's.

The data and code is publicly available. Really sad to see such conspiracy theory posts on a science forum.

[skierinvermont]

Really though, we have better surface datasets to use rather then GISS, such as NCDC, or HADCRUT with UAH infilling on both poles. For the LT (a more accurate reading of the Greater Atmosphere), UAH/RSS are very good there, but cannot really be compared to surface datasets

Basically what I've been saying for a year. Of course GISS agrees strongly with the two data sources you say to use (NCDC and HadCRUT+UAH poles).

[nzucker]

The data and code is publicly available. Really sad to see such conspiracy theory posts on a science forum.

It was sort of a joke, but as Will/ORHWxMan said, it's not hard to imagine how things could be manipulated without "fudging" the data. You've got to be a little suspicious when you see how GISS just blindly applies extreme warm anomalies to the higher latitudes; sure they've been warmer than average, but there is a clear lack of nuance in their extrapolations that is patently obvious when you put the GISS and RSS maps side to side. When you saw Greenland come in like -2C on the RSS analysis, and following the models know there was a PV there, how could GISS be so warm there for March 2010? You refuse to examine the data source critically because you are always in love with the mainstream and trust that our government couldn't possibly be lying. And it just makes sense to me to trust a source like the satellites which is providing real data rather than one whose data is infilled by the main AGW extremist in the US.

[BethesdaWX]

Basically what I've been saying for a year. Of course GISS agrees strongly with the two data sources you say to use (NCDC and HadCRUT+UAH poles).

I prefer to use HADCRUT for the globe due to much higher resolution, as should you HADCRUT (no poles) actually shows cooling since 1998, (peak to peak from 1998-2010 has a +ENSO trend as well), but adding in the Arctic from UAH will reverse that trend. Although this is sort of a moot point altogether. Antarctic has been basically flat since the late 90's.

However, to measure "AGW", a scan of the troposphere itself (UAH/RSS) is a better method than simply surface temperatures, for many reasons.

[tacoman25]

The extraps obviously ARE the reason for the divergence, but that doesn't mean the extraps are wrong. In fact, we know they're right, since when we infill HadCRUT with UAH we get the same result as GISS with only minor differences over the last 30 years.

HadCRUT runs warmer than UAH between 60N and 60S and HadCRUT has very small extrapolation. The raw station data at the surface shows more warming than the satellites. The actual raw surface stations show more warming than the satellites do. This is why the surface data sources show more warming... not the extrapolations. Either the surface has actually warmed more, or more likely, the satellite data is biased cold.

This post doesn't add up, at least not for the period of serious GISS divergence. Since 2005, how much warmer has HadCRUT been running 60/60 than UAH? Very little. GISS has been running warmer both 60/60 and in the Arctic...thus the divergence with all other sources.

I believe the 60/60 trend for HadCRU since 2002 is also lower than GISS. Again, you are confusing things by bringing up the 30 year trend, when we are talking about the period since GISS began diverging.

[ORH_wxman]

This post doesn't add up, at least not for the period of serious GISS divergence. Since 2005, how much warmer has HadCRUT been running 60/60 than UAH? Very little. GISS has been running warmer both 60/60 and in the Arctic...thus the divergence with all other sources.

I believe the 60/60 trend for HadCRU since 2002 is also lower than GISS.

It is...we did that with the graphs earlier in this thread.

[skierinvermont]

This post doesn't add up, at least not for the period of serious GISS divergence. Since 2005, how much warmer has HadCRUT been running 60/60 than UAH? Very little. GISS has been running warmer both 60/60 and in the Arctic...thus the divergence with all other sources.

I believe the 60/60 trend for HadCRU since 2002 is also lower than GISS. Again, you are confusing things by bringing up the 30 year trend, when we are talking about the period since GISS began diverging.

Yes but that divergence is small compared to the divergence between HadCRUT+UAH poles, or GISS, and the satellites. The reason GISS "looks" warm when you compare monthly maps to the satellites is that the actual station data used to make HadCRUT and GISS shows more warming. HadCRUT+UAH poles and GISS have both warmed much more than the satellites, especially UAH, over the last 30 years. That's why GISS (or HadCRUT+UAH infilling) "looks" warm. The actual station data is warmer. It has nothing to do with the extrapolations. Zucker's over and over whining about "a lack of nuance" completely misses the point. There isn't supposed to be. And it has no effect. The reason for the warmth is that the raw station data shows more warming.

If you look at maps there are large areas where GISS extrapolates cooler and warmer than the satellite data. It tends toward warmer not because that is somehow magically inherent in extrapolation (which is stupid and absurd) but because the raw surface station data has tended to warm more than UAH or RSS have. Of course if we use other satellite or radiosonde data we find that GISS (or HadCRUT+UAH poles) have tended too extrapolate cooler, not warmer. It has nothing to do with extrapolation but rather differences in the actual data.

[tacoman25]

Yes but that divergence is small compared to the divergence between HadCRUT+UAH poles, or GISS, and the satellites. The reason GISS "looks" warm when you compare monthly maps to the satellites is that the actual station data used to make HadCRUT and GISS shows more warming. HadCRUT+UAH poles and GISS have both warmed much more than the satellites, especially UAH, over the last 30 years. That's why GISS (or HadCRUT+UAH infilling) "looks" warm. The actual station data is warmer. It has nothing to do with the extrapolations. Zucker's over and over whining about "a lack of nuance" completely misses the point. There isn't supposed to be. And it has no effect. The reason for the warmth is that the raw station data shows more warming.

If you look at maps there are large areas where GISS extrapolates cooler and warmer than the satellite data. It tends toward warmer not because that is somehow magically inherent in extrapolation (which is stupid and absurd) but because the raw surface station data has tended to warm more than UAH or RSS have. Of course if we use other satellite or radiosonde data we find that GISS (or HadCRUT+UAH poles) have tended too extrapolate cooler, not warmer. It has nothing to do with extrapolation but rather differences in the actual data.

You continue to miss the point. We are not talking about the 30 year trend, we are talking about the divergence over the past 7-10 years. GISS has been running warmer 60/60 than HadCRU and UAH during that period. Compare UAH 60/60 to HadCRU 60/60 since 2002.

And GISS only looks warmer in certain spots. As I pointed out, the GISS maps almost always match up very well with AMSU for the U.S. and most of North America. Why doesn't GISS look warmer there, if it's just a matter of the surface warming more? It's almost always in low data/population areas like Greenland, the Arctic, Africa, and parts of Asia where we see significant differences.

[BethesdaWX]

HADCRUT beats GISS Silly regarding Resolution, they are not even worth Comparing. Its simple, HADCRUT 60/60, UAH the rest of the way, and if possible, apply UAH into areas where HADCRUT has no data and extrapolates (africa, south ameica, austrailia, etc).

GISS really shouldn't be defended, its not as good as HADCRUT 60/60, period.

[skierinvermont]

You continue to miss the point. We are not talking about the 30 year trend, we are talking about the divergence over the past 7-10 years.

When one compares monthly maps you ARE talking about the last 30 years. The maps use long-term means.

My whole point is that comparing the monthly maps is plain stupid. And when one does that, you are comparing the past 30 years, because the maps use long-term means.

The reason the monthly maps look warmer for GISS (or HadCRUT+UAH poles) is that over the last 30 years the raw surface station data has warmed more than the satellites (specifically UAH and RSS, not the other satellite/radiosonde data sources). It has nothing to do with the extrapolations.

[nzucker]

Yes but that divergence is small compared to the divergence between HadCRUT+UAH poles, or GISS, and the satellites. The reason GISS "looks" warm when you compare monthly maps to the satellites is that the actual station data used to make HadCRUT and GISS shows more warming. HadCRUT+UAH poles and GISS have both warmed much more than the satellites, especially UAH, over the last 30 years. That's why GISS (or HadCRUT+UAH infilling) "looks" warm. The actual station data is warmer. It has nothing to do with the extrapolations. Zucker's over and over whining about "a lack of nuance" completely misses the point. There isn't supposed to be. And it has no effect. The reason for the warmth is that the raw station data shows more warming.

If you look at maps there are large areas where GISS extrapolates cooler and warmer than the satellite data. It tends toward warmer not because that is somehow magically inherent in extrapolation (which is stupid and absurd) but because the raw surface station data has tended to warm more than UAH or RSS have. Of course if we use other satellite or radiosonde data we find that GISS (or HadCRUT+UAH poles) have tended too extrapolate cooler, not warmer. It has nothing to do with extrapolation but rather differences in the actual data.

Well then maybe we should be checking the stations. How can the satellites show places in Greenland at -2/-3C when GISS shows them well above average? Surely there shouldn't be that much discord between lower troposphere measurements and surface stations in the span of an entire month, especially when models show a 500mb pattern that verifies the type of measurements being done by the satellites. This makes me suspect GISS is using stations that are skewed towards warmth, and then extrapolating these stations over large areas of the Arctic in a fashion that lacks nuance. There is supposed to be high resolution to make an accurate analysis of global temperatures, GISS fails to provide that, so I toss it. Nice and simple. My point about missing nuance is valid and one that has been stated many times by Tacoman, who has also complained that GISS maps look much less realistic than the satellites in their spatial anomalies, i.e. you can just tell that a given 500mb pattern that you've observed on modeling would likely produce an anomaly pattern more similar to the satellites than to GISS.

Of course it has to do with extrapolation, you can clearly spot more areas that were extrapolated warmer on GISS maps than areas that were extrapolated cooler compared to the satellites. It's a no-brainer.

[tacoman25]

When one compares monthly maps you ARE talking about the last 30 years. The maps use long-term means.

My whole point is that comparing the monthly maps is plain stupid. And when one does that, you are comparing the past 30 years, because the maps use long-term means.

The reason the monthly maps look warmer for GISS (or HadCRUT+UAH poles) is that over the last 30 years the raw surface station data has warmed more than the satellites (specifically UAH and RSS, not the other satellite/radiosonde data sources). It has nothing to do with the extrapolations.

1. No, just because the maps have longterm means does not mean that I am talking about the last 30 years. That has to be one of the most illogical things I've heard you say.

2. You continue to ignore the fact that GISS has diverged over the past decade, due to the fact that despite whatever 30 year trends exist, they have been running warmer than other sources, both in the Arctic and 60/60. The fact that this is due to their extrapolations is supported by the fact that the places they don't match up well with AMSU maps is almost always in low population/low data areas. The U.S. almost always matches up great. You have failed to offer any real answer to this. All you do is repeat 30 year trends and your belief that extrapolation in incapable of being too warm. Your mind is closed.

[nzucker]

1. No, just because the maps have longterm means does not mean that I am talking about the last 30 years. That has to be one of the most illogical things I've heard you say.

2. You continue to ignore the fact that GISS has diverged over the past decade, due to the fact that despite whatever 30 year trends exist, they have been running warmer than other sources, both in the Arctic and 60/60. The fact that this is due to their extrapolations is supported by the fact that the places they don't match up well with AMSU maps is almost always in low population/low data areas. The U.S. almost always matches up great. You have failed to offer any real answer to this. All you do is repeat 30 year trends and your belief that extrapolation in incapable of being too warm. Your mind is closed.

One of the problems I have with arguing with skier is that he frequently becomes obstinate and just disregards arguments from the opposing viewpoint once he's made up his mind. I've mentioned problems with GISS spatial analysis in certain areas of the globe, particularly the Arctic and Greenland, several times. Instead of providing real data, such as the anomalies for each station and how far they are extrapolated, to back up his contention that GISS extrapolations are accurate and not linked to a warm bias, skier just repeats the same trite "Law of Large Numbers" line over and over again, not understanding that this is not even the correct mathematical concept for such a situation. He keeps saying "Well the code is available, it can't be biased or a conspiracy" but he never actually supplies any meat to the debate such as the maps I have found comparing GISS with RSS for each month. I have also asked several times about how GISS can be trusted for regional studies of climate change given its history of large-scale extrapolations and frequently dubious anomalies in low-population regions, and skier has never answered this query either. What if I wanted to use NASA data for a study of Greenland winter temperatures....how could I possibly do this with a 5C discrepancy between RSS and GISS for March 2011 as well as a clearly nonsensical anomaly distribution that doesn't correlate to a 500mb pattern shown by guidance? Shouldn't we be challenging ourselves to get more regions' data absolutely correct, instead of just relying on extrapolations evening out.

And GISS isn't evening out. We aren't talking about 30 years, we are talking about 10 years, or the "since Hansen got desperate" period as I prefer to name it. But the large differences between GISS and satellite analysis in sparse data regions are not being improved or corrected; they appear to be getting worse in my eyes, with December 2010 and March 2011 two of the most heinous GISS anomaly maps I've ever seen. GISS shows a warming trend of .12C/decade since the turn of the millennium, whereas UAH and RSS show .07C/decade, or half of that. Some questions clearly need to be answered about NASA data collection, station drop-out, the pattern of extrapolation, etc. Skier constantly claims that the data couldn't be exploited to satisfy a warm bias, but then he continually ignores the very questions that need responses to prove the lack of bias.

[skierinvermont]

Well then maybe we should be checking the stations. How can the satellites show places in Greenland at -2/-3C when GISS shows them well above average? Surely there shouldn't be that much discord between lower troposphere measurements and surface stations in the span of an entire month, especially when models show a 500mb pattern that verifies the type of measurements being done by the satellites. This makes me suspect GISS is using stations that are skewed towards warmth, and then extrapolating these stations over large areas of the Arctic in a fashion that lacks nuance. There is supposed to be high resolution to make an accurate analysis of global temperatures, GISS fails to provide that, so I toss it. Nice and simple. My point about missing nuance is valid and one that has been stated many times by Tacoman, who has also complained that GISS maps look much less realistic than the satellites in their spatial anomalies, i.e. you can just tell that a given 500mb pattern that you've observed on modeling would likely produce an anomaly pattern more similar to the satellites than to GISS.

Of course it has to do with extrapolation, you can clearly spot more areas that were extrapolated warmer on GISS maps than areas that were extrapolated cooler compared to the satellites. It's a no-brainer.

There is not "supposed to be" and there definitely does not need to be high resolution to measure global temperature. You can form an accurate index of temperature by randomly selecting a mere 70 stations and then extrapolating the 1000s of miles between them. The result doesn't change if you use 70, 500, 5,000 or 50,000 stations. +.8C/century.

The large discrepancies where GISS runs 2-5C cooler or warmer than UAH are due to the extrapolations. However, mathematically these balance out. The slight extra warming on GISS is due to the surface stations warming more than UAH.

Maybe we should be "checking" the satellites considering they're not very accurate and other satellite data sources say GISS is too cold. I guess GISS extrapolations are causing a cold bias!!! OH NOES!

[skierinvermont]

1. No, just because the maps have longterm means does not mean that I am talking about the last 30 years. That has to be one of the most illogical things I've heard you say.

2. You continue to ignore the fact that GISS has diverged over the past decade, due to the fact that despite whatever 30 year trends exist, they have been running warmer than other sources, both in the Arctic and 60/60. The fact that this is due to their extrapolations is supported by the fact that the places they don't match up well with AMSU maps is almost always in low population/low data areas. The U.S. almost always matches up great. You have failed to offer any real answer to this. All you do is repeat 30 year trends and your belief that extrapolation in incapable of being too warm. Your mind is closed.

I'm not saying that GISS 60/60 hasn't diverged from HadCRUT 60/60 over the last 8 years. That is an obvious fact. What I am saying is that comparing the monthly maps and going OOOH look GISS extrapolated too warm there is absurd. The map looks warmer because of a 30 year divergence between GISS and UAH. Why? Because the surface stations have warmed more.

Both HadCRUT 60/60 and GISS 60/60 show more warming than the satellites the last 30 years. This is due to the surface stations warming more and has nothing to do with the extrapolations. Extrapolation doesn't create a bias. It is mathematically impossible. It is not "closed minded" to understand mathematical facts.

[skierinvermont]

And GISS isn't evening out. We aren't talking about 30 years, we are talking about 10 years, or the "since Hansen got desperate" period as I prefer to name it.

Really sad to see such conspiracy theory posts on a science forum. The methodology and data hasn't changed since GISS was first developed. Hansen didn't "get desperate" and make it warmer magically.

You just keep pointing out the monthly maps and ignoring the fact that there are large areas that are extrapolated too cold as well. GISS runs warmer than UAH not because of the extrapolations, but because the surface data has actually warmed more. Which is why HadCRUT 60S-60N has also warmed much more than UAH or RSS. You have yet to address either of these points and instead you just respond with your typical off-point personal attacks. Very very sad.

One of the problems I have with arguing with skier is that he frequently becomes obstinate and just disregards arguments from the opposing viewpoint once he's made up his mind.

I have made a promise to be better about the personal attacks, and will try to adhere to it.

So much for this "promise." It is very disappointing that you can't abstain from attacking the person and stick to the substance. I am not disregarding your viewpoint. I have given several clear reasons why it is blatantly wrong which you have not responded to.

[tacoman25]

I'm not saying that GISS 60/60 hasn't diverged from HadCRUT 60/60 over the last 8 years. That is an obvious fact. What I am saying is that comparing the monthly maps and going OOOH look GISS extrapolated too warm there is absurd. The map looks warmer because of a 30 year divergence between GISS and UAH. Why? Because the surface stations have warmed more.

Both HadCRUT 60/60 and GISS 60/60 show more warming than the satellites the last 30 years. This is due to the surface stations warming more and has nothing to do with the extrapolations. Extrapolation doesn't create a bias. It is mathematically impossible. It is not "closed minded" to understand mathematical facts.

Then why do the maps almost always match up well for the U.S. and other areas with abundant data/stations, but the places they don't tend to be sparse data regions like Africa, the Arctic/Greenland, and parts of Asia? 2+2 = 4, but you are insisting this isn't the case. If what you were claiming were true, the AMSU and GISS maps wouldn't match up well over most of the globe...but they do.

And it is not mathematically impossible to have a warm bias with extrapolation. In a perfect world, extrapolation shouldn't lead to a warm/cold bias, but because global temperatures are not evenly distributed, it is very possible. If localized stations develop greater warming for whatever reason, that can be extrapolated over a huge area, when it may just be a localized effect. There could easily be an imbalance between stations that have warming and those that have cooler temps.

[skierinvermont]

Then why do the maps almost always match up well for the U.S. and other areas with abundant data/stations, but the places they don't tend to be sparse data regions like Africa, the Arctic/Greenland, and parts of Asia? 2+2 = 4, but you are insisting this isn't the case. If what you were claiming were true, the AMSU and GISS maps wouldn't match up well over most of the globe...but they do.

And it is not mathematically impossible to have a warm bias with extrapolation. In a perfect world, extrapolation shouldn't lead to a warm/cold bias, but because global temperatures are not evenly distributed, it is very possible. If localized stations develop greater warming for whatever reason, that can be extrapolated over a huge area, when it may just be a localized effect. There could easily be an imbalance between stations that have warming and those that have cooler temps.

No.. AMSU and GISS shouldn't match up across the rest of the globe. That is absurd. Because of the extrapolations GISS will be much cooler and much warmer in large areas. There is a tendency towards warmth, because the surface stations have warmed more than the satellites (which is an undeniable fact because HadCRUT 60-60 and GISS 60-60, which have much less extrapolation, have both warmed more than UAH or RSS). This unambiguously proves the reason for the greater warmth on GISS (or HadCRUT+UAH poles) is not the extrapolation. Even when you take away the extrapolation, and look only at HadCRUT 60-60, there is greater warming than on UAH or RSS.

It's pretty funny watching everybody go ape-**** over extrapolation when the actual reasons for the divergence between GISS and HadCRUT can be found if you take the time to examine their methodology in detail.