Giss versus UAH: 85,7% more warming after 30 years!
Global Temperature 1979-2008 marks an anniversary of 30 years of temperature history of the satellite era. Since the World Meteorological Organization has defined “climate” as “the average weather” over a classical period of 30 years, we have now a record of a full climate period of near surface temperatures as measured by satellites. This is particularly interesting because surface temperatures records by surface stations are contineously critized as being contaminated by the urban heat island effect of a growing population around the station (UHI effect).
Let’s look at the above graph. At first glance, the five datasets follow more an less the same trend. I have re-baselined the graph by attributing index 0 (zero) to the average temperature of start year 1979 for each metric. Now look at the result:
The temperature of the satellite MSU unit of the University of Alabama indicated thus that temperature in 2008 was +0,28°C above 1979. At the same time, temperature by Giss Nasa land-ocean index rose +0,52°C which indeed means 85,7% more warming of Giss land-ocean compared to UAH-MSU after 30 years of satellite measurements of near surface temperature (lower troposphere). The long-term trendline shows a slope of +0,127°C resp. +0,162°C per decade, which means 27,6% more warming at Giss Nasa. The reason why the long-term trend difference (+27,6%) lags so much behind the difference in 2008 (+85,7%) is partly due to super El Nino 1997-1998 which boosted near-surface temperature (UAH and RSS) according to satellites significantly above surface temperature, thus partly offsetting the relative cooling. Moreover, opponants of the mainstream view regarding global warming suggest that Giss final temperature data is hand edited which raises questions why temperature of this most cited data set by global warming proponents rose strongly during the early eighties (which satellites didn’t confirm) and why in most recent years, Giss still claimed a slight warming while other measurements suggested a cooling, thus increasing the bias even more .
The stronger warming of the surface is particularly disturbing after reading that
Climate models predict that as the surface warms, so should the global troposphere. Globally, the troposphere (measured by satellites) should warm about 1.2 times more than the surface; in the tropics, the troposphere should warm about 1.5 times more than the surface.
Source: The Air Vent.
The opposite of what the climate models predict is happening. One last example. Remember when Giss Nasa published the October data which they had to correct down from + 0.73°C to +0.55°C. In the meantime, they corrected it back up to +0.58°C. It’s good there is competition between more or less different datasets and networks. Climate alarmist James Hansen heads the temperature index with the biggest warming and climate skeptic Roy Spencer the satellite unit with the least warming. Can it be just coincidence?
your analysis is lousy.
looking at the trends, gives a completely different picture:
http://www.woodfortrees.org/plot/gistemp/from:1979/trend/plot/hadcrut3vgl/from:1979/trend/plot/uah/from:1979/trend/plot/rss/from:1979/trend
you do understand, that looking at the start and end point is NOT the way to analyse 30 years of data, don t you?
@sod
Different than the slope of the trendline of Giss being 27,6% steeper than UAH as discribed above?
Different than the slope of the trendline of Giss being 27,6% steeper than UAH as discribed above?
well, 27% is very different from 85%.
and you didn t check my link, did you?
3 of 4 available data sets show a very similar trend over those 30 years. the real question is: why does UAH differ from the other 3 by 27%?
Sure, 27% is the slope difference and 85% is the final index difference of 2008 versus 1979. I thought it was well documented above. And yes, I did read your link. In a former post I gave trend updates as of October 2008, just after Mears adjusted their RSS dataset downward.
Satellites:
UAH + 0.127/decade (unchanged)
RSS + 0.159/decade (old + 0.169)
Surfaces:
Giss + 0.161/dec.
HadCrut3 + 0.16/dec.
NCDC + 1.627/dec.
Does Giss have the most significant warming? No, it’s NCDC. Are Giss, HadCrut3, NCDC and RSS similar? Yes, you are right.
so will you change your title?
“what the heck is wrong with the low UAH 30 years warming trend” would be a good start…
Not quite, Sod.
There are still unresolved past issues in both satellite data for sure. However, RSS did an excellent analysis using samplings to compare same pixels of the global picture of the two satellite measurements and some radiosonde measurements. Their own conclusion is not only a better agreement between UAH and radiosondes compared to RSS in the tropics but also a striking agreement between the sampled trends between 75S and 75N between UAH and HadAT. Of course, everyone is free to draw their own conclusions from this. This is certainly not the end of the story.