tacoman25 Posted February 12, 2011 Share Posted February 12, 2011 I'd love to see this.. were you doing it for particular months? particular years? or 30 year year trends? I'd really only be interested if it were the latter. And if you were doing the latter.. I highly doubt you would have been able to eyeball the difference, since globally GISS and RSS differ by only .01C/decade... a difference I highly doubt you would have been able to detect simply looking at maps. Moreover, the same objection I raised before still applies - you can't use RSS to crosscheck GISS, since what occurs at the surface will be different than in the troposphere. And the other objection I raised applies as well, RSS contains significant errors that have yet to be worked out and which likely bias it cold. So you are using data which might be quite flawed to cross-check GISS.. doesn't make much sense to me. Unfortunately, the computer I had it saved on is gone and the old forum server is as well. So why do you think .01C/decade difference is insignifcant, but .02C/decade is huge? Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 Yes, it varies depending on what year you choose. Over time, it appears they are moving closer together, as far as longterm trend. Yes.. I am aware that UAH and RSS have been converging since the late 90s. However, there is still a substantial long term divergence. That simply speaks to how much more warming RSS shows from 1979 (or 1980) to 1995. As I said before, the difference is attributable to differences in methodology. You seem to have misinterpreted me.. Im not saying the difference is massive or anything. I'm saying two things: 1) The difference is larger than the difference between the other data sources, so it is odd that GISS gets singled out even though UAH is the biggest outlier. 2) It indicates there is still substantial uncertainty in the satellite analyses (which is why using UAH or RSS to cross-check GISS is just silly). It could be that a proper analysis would show even more warming than GISS. (It just so happens that other analyses DO show exactly that - STAR, Fu, Vinnikov etc.) The divergence between UAH and RSS from 1980-1995 is much larger than the convergence 1995-2010: Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 Unfortunately, the computer I had it saved on is gone and the old forum server is as well. So why do you think .01C/decade difference is insignifcant, but .02C/decade is huge? See above - I'm not saying it's huge. Also, the .01C/decade difference between GISS and Had is mostly attributable to Had not including the rapid warming in the arctic. Link to comment Share on other sites More sharing options...
tacoman25 Posted February 12, 2011 Share Posted February 12, 2011 Yes.. I am aware that UAH and RSS have been converging since the late 90s. However, there is still a substantial long term divergence. That simply speaks to how much more warming RSS shows from 1979 (or 1980) to 1995. As I said before, the difference is attributable to differences in methodology. You seem to have misinterpreted me.. Im not saying the difference is massive or anything. I'm saying two things: 1) The difference is larger than the difference between the other data sources, so it is odd that GISS gets singled out even though UAH is the biggest outlier. 2) It indicates there is still substantial uncertainty in the satellite analyses (which is why using UAH or RSS to cross-check GISS is just silly). It could be that a proper analysis would show even more warming than GISS. (It just so happens that other analyses DO show exactly that - STAR, Fu, Vinnikov etc.) The divergence between UAH and RSS from 1980-1995 is much larger than the convergence 1995-2010: Well, I don't think there is a huge difference in the historical significance of 10, 20, or 30 year trends. Statistically, there is just likely to be more variance in shorter term trends. One difference between the recent divergence of GISS, and the divergence between UAH/RSS: Hadley and GISS were kind of in the middle back in the 1980s when UAH and RSS had the big difference. Over the past decade or so, though, GISS has been the clear, single outlier. That is why they have been singled out more. Also, people tend to single out GISS because they are headed by a political activist. Hansen is simply a more polarizing figure who draws attention to himself and his organization. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 Also, the .01C/decade difference between GISS and Had is mostly attributable to Had not including the rapid warming in the arctic. GISS has too much warming in the arctic, is the problem, and HADLEY has more data, but doesn't extrapolate it where there is no data available. GISS would be better off filling in the Arctic with UAH data rather than making its own data up. Its not that HADCRUT is too cool, its that GISS is too warm. FYI, the arctic had been cooling until the mid 90's. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 GISS has too much warming in the arctic, is the problem, and HADLEY has more data, but doesn't extrapolate it where there is no data available. GISS would be better off filling in the Arctic with UAH data rather than making its own data up. Its not that HADCRUT is too cool, its that GISS is too warm. FYI, the arctic had been cooling until the mid 90's. No, it's both. If you used UAH data to fill in the arctic on HadCRUT, HadCRUT would be significantly warmer and much closer to GISS. UAH shows 1.5C of warming in the arctic since 1990 which HadCRUT completely leaves out. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 Where Hadley has data, it has run much cooler than GISS and its extrapolations. GISS should fill in the Arctic with UAH anomalies instead of making it up its own. Edit: yes, satellites do show the "middle road" scenario"... probably gives it a higher verification chance. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 Where Hadley has data, it has run much cooler than GISS and its extrapolations. GISS should fill in the Arctic with UAH anomalies instead of making it up its own. Edit: yes, satellites do show the "middle road" scenario"... probably gives it a higher verification chance. Actually where Hadley and GISS both have coverage they are fairly similar.. the primary difference is Hadley leaves out the arctic. If you took Hadley and filled in the arctic with UAH data, it would be warmer and more in line with GISS. And of course over the long run (which is of course more important) HadCRUT shows MORE warming than GISS. HadCRUT is .73C/century GISS is .66C/century since 1900. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 Actually where Hadley and GISS both have coverage they are fairly similar.. the primary difference is Hadley leaves out the arctic. If you took Hadley and filled in the arctic with UAH data, it would be warmer and more in line with GISS. Where HADLEY has Data, it has run cooler than GISS...heck, there are some below avg anoms in there UAH is colder than GISS. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 Where HADLEY has Data, it has run cooler than GISS...heck, there are some below avg anoms in there UAH is colder than GISS. That animation uses different baselines. I also see several areas where HadCRUT is warmer (Australia, parts of Africa, the Great Lakes up towards Hudson Bay and just west of Hudson Bay, Southern California, northern Europe). The rest of the difference can be accounted for by the use of different baselines. We know for a fact that GISS is cooler over the rest of the world because the long term trend on GISS is LOWER than the long term trend on HadCRUT (since 1900). And this is DESPITE the fact that GISS extrapolates warmth into the rest of the arctic. Over the rest of the earth GISS is MUCH cooler than HadCRUT. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 That animation uses different baselines. Well, Obviously it does However, that does not change the fact that where HADCRUT has data, it is colder than GISS. The 1960-1990 base should be colder than the 1950-1980 base in the arctic. The Ice conditions up there from the 1940-1960 timeframe were almost as bad as todays. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 Well, Obviously it does However, that does not change the fact that where HADCRUT has data, it is colder than GISS. The 1960-1990 base should be colder than the 1950-1980 base in the arctic. The Ice conditions up there from the 1940-1960 timeframe were almost as bad as todays. And if you used the same baseline, you would see that GISS is not running warmer than HadCRUT over the areas they both cover. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 And if you used the same baseline, you would see that GISS is not running warmer than HadCRUT over the areas they both cover. No, even with the baseline change, HADCRUT data runs cooler. Also depends if you use the baseline of the Arctic, or the globe. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 Depends if you use the baseline of the Arctic, or the globe. Either way, HADCRUT data runs cooler even with the baseline change. No it doesn't ... GISS has a lower long term trend. In the past 10 years GISS has spiked but this spike is primarily due to the arctic which HadCRUT does not include. Over the rest of the earth, GISS still runs cooler. Here is the same map as the animation you took from a WUWT post, but using the 1961-1990 baseline for GISS, instead of the 1951-1980 baseline that it typically uses. As you can see, the anomalies on GISS especially over the southern ocean are substantially reduced by using the correct 1961-1990 baseline. And here is the animation from WUWT again: http://wattsupwiththat.com/2010/05/18/gistemp-vs-hadcrut/ Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 No it doesn't ... GISS has a lower long term trend. In the past 10 years GISS has spiked but this spike is primarily due to the arctic which HadCRUT does not include. Over the rest of the earth, GISS still runs cooler. Here is the same map as the animation you took from a WUWT post, but using the 1961-1990 baseline for GISS, instead of the 1951-1980 baseline that it typically uses. As you can see, the anomalies on GISS especially over the southern ocean are substantially reduced by using the correct 1961-1990 baseline. It is still Colder. Where GISS doesn't extrapolate, then yes. it is still colder than HADCRUT in the Arctic,and southern ocean. I'll paste these together for you using your post. Ignore the top image! HADCRUT is still colder. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 This is also a classic example of the deception used on WUWT.. in the first two side by side images in the WUWT post they use 1961-1990 as the baseline for both images. However, when they go to the flashing animation back and forth between them, Watts uses the 1951-1980 baseline for GISS and the 1961-1990 baseline for HadCRUT. Extremely deceptive. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 12, 2011 Share Posted February 12, 2011 No it's not still colder.. when you use the same baseline and the same extrapolation distance (which is what the flash animation you posted is doing except it failed to use the same baselines) Had has an anomaly of .48C and GISS has an anomaly of .49C - statistically the same. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 This is also a classic example of the deception used on WUWT.. in the first two side by side images in the WUWT post they use 1961-1990 as the baseline for both images. However, when they go to the flashing animation back and forth between them, Watts uses the 1951-1980 baseline for GISS and the 1961-1990 baseline for HadCRUT. Extremely deceptive. Its also deceptive to the public when GISS uses the earlier baseline to make things look warmer. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 12, 2011 Share Posted February 12, 2011 No it's not still colder.. when you use the same baseline and the same extrapolation distance (which is what the flash animation you posted is doing except it failed to use the same baselines) Had has an anomaly of .48C and GISS has an anomaly of .49C - statistically the same. It is colder. .48C is not colder than .49C? HADCRUT is still alot Colder in the arctic, and its expanse of cold anoms is larger in the southern ocean. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 13, 2011 Share Posted February 13, 2011 It is colder. .48C is not colder than .49C? HADCRUT is still alot Colder in the arctic, and its expanse of cold anoms is larger in the southern ocean. .48C is not significantly different from .49C and you certainly wouldn't be able to observe it simply looking at maps of the two. Both GISS and HadCRUT have error bars for a single year of .05C -.1C. So a difference of .01C is completely meaningless and you wouldn't be able to observe it looking at a map. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 13, 2011 Share Posted February 13, 2011 .48C is not significantly different from .49C and you certainly wouldn't be able to observe it simply looking at maps of the two. Both GISS and HadCRUT have error bars for a single year of .05C -.1C. So a difference of .01C is completely meaningless and you wouldn't be able to observe it looking at a map. .48 is colder than .49, end of discussion. GISS is still warmer in the arctic even with the same baseline. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 13, 2011 Share Posted February 13, 2011 .48 is colder than .49, end of discussion. GISS is still warmer in the arctic even with the same baseline. GISS is warmer in the arctic because HadCRUT doesn't include 90% of the arctic. The flash animation you posted compares images from 2005 using a 1951-1980 baseline for GISS 250km smoothing compared to a 1961-1990 baseline HadCRUT image, and concludes that the GISS image looks warmer. That is in fact true, the GISS image has a computed anomaly of .56C while the HadCRUT image has a computed anomaly of .48C - a discrepancy of .08C which is large enough to observe with the naked eye. However, when we use the 1961-1990 baseline for GISS the computed anomaly drops to .49C.. a rather trivial discrepancy of only .01C from the HadCRUT image which one cannot observe with the naked eye. WUWT author Steven Goddard exaggerated the discrepancy between HadCRUT and GISS 250km smoothing by 800% by using a different baseline. This is classic WUWT trickery. Goddard is familiar enough with the two data sources to know that they use different baselines and he even used the same baselines in his first set of images. But then in his animation, he goes back to using a 1951-1980 baseline for GISS. He even intentionally photo shopped out the computed anomalies that automatically appear on images generated from the GISS website because this would have allowed intelligent readers to figure out that there was a base change occurring. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 13, 2011 Share Posted February 13, 2011 GISS is warmer in the arctic because HadCRUT doesn't include 90% of the arctic. No, I meant where HADCRUT and GISS both have data (in the arctic), even using the 1961-1990 baseline for both, GISS runs warmer still. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 13, 2011 Share Posted February 13, 2011 No, I meant where HADCRUT and GISS both have data (in the arctic), even using the 1961-1990 baseline for both, GISS runs warmer still. No it doesn't.. globally GISS 250km smoothing has an anomaly of .49C while HadCRUT has an anomaly of .48C. You would not be able to observe this visually. I can see multiple areas where HadCRUT was warmer and multiple areas where GISS was warmer. A difference of .01C is not detectable visually.. unless you are some kind of savant. And the difference is not statistically meaningful considering HadCRUT has annual error bars of +/- .05C. Link to comment Share on other sites More sharing options...
beneficii Posted February 13, 2011 Share Posted February 13, 2011 .48 is colder than .49, end of discussion. Statistically speaking, not if they fall within the margin of error of each other. In that case, they would be statistically equal. That is skierinvermont's point. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 13, 2011 Share Posted February 13, 2011 No it doesn't.. globally GISS 250km smoothing has an anomaly of .49C while HadCRUT has an anomaly of .48C. You would not be able to observe this visually. I can see multiple areas where HadCRUT was warmer and multiple areas where GISS was warmer. A difference of .01C is not detectable visually.. unless you are some kind of savant. And the difference is not statistically meaningful considering HadCRUT has annual error bars of +/- .05C. huh? .48C and .49C are the global anoms. HADCRUT is cooler regardless, I never mentioned significance. In the arctic, its obvious there are more red squares on GISS where HADCRUT has Orange than visa versa. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 13, 2011 Share Posted February 13, 2011 Statistically speaking, not if they fall within the margin of error of each other. In that case, they would be statistically equal. That is skierinvermont's point. That was never my point though, so skier should not intertwine seperate notions. Link to comment Share on other sites More sharing options...
skierinvermont Posted February 13, 2011 Share Posted February 13, 2011 That was never my point though, so skier should not intertwine seperate notions. You claim to be able to observe the difference between .48C and .49C simply by looking at the two maps and I am saying that you can't. The difference is too small to be able to observe visually. The comparison basically confirms my point that when the extrapolations across the arctic are removed, HadCRUT and GISS are essentially the same (.48C vs .49C). When extrapolations across the arctic are included the difference grows from .48C vs .49C to .48C vs .56C. Link to comment Share on other sites More sharing options...
BethesdaWX Posted February 13, 2011 Share Posted February 13, 2011 You claim to be able to observe the difference between .48C and .49C simply by looking at the two maps and I am saying that you can't. The comparison basically confirms my point that when the extrapolations across the arctic are removed, HadCRUT and GISS are essentially the same (.48C vs .49C). When extrapolations across the arctic are included the difference grows from .48C vs .49C to .48C vs .56C. waaaaaaaat? I never said that. The anoms are listed on the images. Link to comment Share on other sites More sharing options...
tacoman25 Posted February 13, 2011 Share Posted February 13, 2011 No it doesn't.. globally GISS 250km smoothing has an anomaly of .49C while HadCRUT has an anomaly of .48C. You would not be able to observe this visually. I can see multiple areas where HadCRUT was warmer and multiple areas where GISS was warmer. A difference of .01C is not detectable visually.. unless you are some kind of savant. And the difference is not statistically meaningful considering HadCRUT has annual error bars of +/- .05C. ORHwx has referenced data that indicates GISS is warmer over parts of the Arctic covered by HadCRU as well. Link to comment Share on other sites More sharing options...
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