It has been a while since I’ve presented the GISS, UK Met Office and NCDC global land surface air temperature plus sea surface temperature products. I’ve decided to add them to the datasets I update monthly.
I’ll present each of the datasets individually, starting in January 1979, using the suppliers’ standard base years for anomalies. 1979 is the start year of the lower troposphere temperature products (not included), so it’s a logical start time for these short-term data presentations. The GISS, UK Met Office and NCDC products with linear trends are then presented in a comparison graph, using the base years of 1981-2010. And for those wanting a better look at the most recent wiggles, the last comparison graph starts in January 2003—the last decade plus. The final graph is the average of the 3 products.
GISS LAND OCEAN TEMPERATURE INDEX (LOTI)
Introduction: The GISS Land Ocean Temperature Index (LOTI) data is a product of the Goddard Institute for Space Studies. Starting with their January 2013 update, it uses NCDC ERSST.v3b sea surface temperature data. The impact of the recent change in sea surface temperature datasets is discussed here. GISS adjusts GHCN and other land surface temperature data via a number of methods and infills missing data using 1200km smoothing. Refer to the GISS description here. Unlike the UK Met Office and NCDC products, GISS masks sea surface temperature data at the poles where seasonal sea ice exists, and they extend land surface temperature data out over the oceans in those locations. Refer to the discussions here and here. GISS uses the base years of 1951-1980 as the reference period for anomalies. The data source is here.
Update: The February 2013 GISS global temperature anomaly is 0.49 deg C. It dropped -0.11 deg C since January 2013.
GISS LOTI
UK MET OFFICE HADCRUT4
Introduction: The UK Met Office HADCRUT4 dataset merges CRUTEM4 land-surface air temperature dataset and the HadSST3 sea-surface temperature (SST) dataset. CRUTEM4 is the product of the combined efforts of the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia. And HadSST3 is a product of the Hadley Centre. Unlike the GISS and NCDC products, missing data is not infilled in the HADCRUT4 product. That is, if a 5-deg latitude by 5-deg longitude grid does not have a temperature anomaly value in a given month, it is not included in the global average value of HADCRUT4. The HADCRUT4 dataset is described in the Morice et al (2012) paper here. The CRUTEM4 data is described in Jones et al (2012) here. And the HadSST3 data is presented in the 2-part Kennedy et al (2012) paper here and here. The UKMO uses the base years of 1961-1990 for anomalies. The data source is here.
Update: The February 2013 HADCRUT4 global temperature anomaly is +0.48 deg C. It increased +0.05 deg C since January 2013.
HADCRUT4
NCDC GLOBAL SURFACE TEMPERATURE ANOMALIES
Introduction: The NOAA Global (Land and Ocean) Surface Temperature Anomaly dataset is a product of the National Climatic Data Center (NCDC). NCDC merges their Extended Reconstructed Sea Surface Temperature version 3b (ERSST.v3b) with the Global Historical Climatology Network-Monthly (GHCN-M) version 3.2.0 data for land surface air temperature anomalies. NOAA infills missing data for both land and sea surface temperature datasets using methods presented in Smith et al (2008). The data source is here. NCDC uses 1901 to 2000 for the base years for anomalies.
Update: The February 2013 NCDC global land plus sea surface temperature anomaly is +0.58 deg C. It increased +0.04 deg C since January 2013.
NCDC
COMPARISON
The three datasets are compared in the next two time-series graphs. The first graph compares the GISS, HADCRUT4 and NCDC global surface temperature anomaly products starting in 1979. It also includes the linear trends. Because the three datasets share common source data, (GISS and NCDC also use the same sea surface temperature data) it should come as no surprise that they are so similar. For those wanting a closer look at the more recent wiggles, the second graph starts in 2003. Both of the comparisons present the anomalies using the base years of 1981 to 2010. Referring to their discussion under FAQ 9 here, according to NOAA:
This period is used in order to comply with a recommended World Meteorological Organization (WMO) Policy, which suggests using the latest decade for the 30-year average.
Comparison Starting in 1979
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Comparison Starting in 2003
AVERAGE
The last graph presents the average of the GISS, HADCRUT and NCDC land plus sea surface temperature anomaly products. The flatness of the data since 2001 is very obvious, as is the fact that surface temperatures have rarely risen above those created by the 1997/98 El Niño.
Average of Global Land+Sea Surface Temperature Anomaly Products
‘Rarely’ risen above the 97/98 el-nino? Once!
And then, dropped like a brick parachute.
I would also like to mention something I saw on another skeptic blog- Chiefio, I believe.
He showed a temperature reconstruction of the past century (give or take), and it appeared (to me) that there was a large temperature spike right before each cooling period.
Rather like the el-nino of 97/98.
It may just be an artefact. But it seemed significant……?
Nice work Bob. Is there a comparable graph of raw data?
Great work. Would you consider adding a ‘trend of the trend’ from any fair start point, for those convinced that the latest temperature additions are not adding to ‘warmist’s’ fears?
Bob, good presentation. Couple of questions about plotting these things.
The data look like something other than a linear trend should be used. Looks like one wouldn’t get a meaningful “r-square” from that line.
Are these data sufficiently good to get averages of two decimal places and slopes to three?
Nice article. It may have been illuminating to see another set of graphs grouping the satellite data together as a contrast to the three sets you wrote about. I do not feel thel land based data represents the true surface temps due to siting/homogenization issues, and so anyone reading the article will believe the Earth temps are actually that high they should be, even if it is flatlined recently.
Bob says: April 1, 2013 at 4:27 am Looks like one wouldn’t get a meaningful “r-square” from that line.
There are dangers in using smoothed data or averaged data for correlation coefficients.
http://wattsupwiththat.com/2013/03/30/the-pitfalls-of-data-smoothing/
and within, as complementary material, Geoff Sherrington says, March 30, 2013 at 8:38 pm
Bloke down the pub says: “Is there a comparable graph of raw data?”
I didn’t prepare one due to the differences in the base years.
When I look at those graphs, I see a peak that is now on its way down. What is that straight line doing there? Don’t even the most simple people working with numbers realize that there is no such thing as a straight line? Didn’t we all learn sometime before even beginning school that just because something has been a certain way in the past doesn’t mean it will be the same in the future?
Again I say: if only “we” had spent the research money trying to determine the actual cause of the 20th century warming, instead of simply assuming it was CO2. It might be important to know, as the cooling begins in earnest. I’m not looking forward to more winters like we had in the 70s.
Bob says: “Are these data sufficiently good to get averages of two decimal places and slopes to three?”
That’s for you to decide. I simply plot what they present.
Regards
I continue to be fascinated by climate scientists’ vision of themselves as the modern day, real world, much improved Rumpelstiltskin, able not only to spin straw (bad data) into gold (good “data”), but also to spin nothing (missing data) into gold (good “data”). This suggests to me that the current state of climate science is Grimm.
nuwurld says: “Would you consider adding a ‘trend of the trend’ from any fair start point, for those convinced that the latest temperature additions are not adding to ‘warmist’s’ fears?”
It’s quite remarkable how the linear trend line obscures the recent flattening of rise in global temperatures.
Thanks Bob. I don’t know why you are considering the GISS temperature analysis – their algorithm and software are equally bad…
Roughly speaking, the first third and last third of the data look flat, while the middle third looks like it could be represented by an upward trend. Isn’t that more suggestive of some sort of oscillation rather than an overall upward trend?
It would be instructive (to me at least) to plot the annual change in additional CO2 attributed to human industrial activity on the RHS y axis. Are there a significant difference in subsets of the global data for the northern and southern hemispheres?
There it goes again: The sinoidal kurve with an 11-year-interval between highs and lows is visible in all these curves.
Sounds familiar? That’s because it is: “IT’S THE SUN, STOOPIDS!”
And by that I don’t mean neither the WUWT-authors nor it’s readership.
“Melt may explain Antarctica’s sea ice expansion”
http://www.bbc.co.uk/news/science-environment-21991487
Then I saw it
“They tried to reproduce the observed changes in a computer-based climate model.”
Thanks, Bob. Good work!
It was surprising to find that even http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif shows no warming since 2002. But given the flawed methodology and adjusted data this adds nothing to what is available.
@Bob Tisdale: “It’s quite remarkable how the linear trend line obscures the recent flattening of rise in global temperatures.”
After hearing people claim that the pause is not official until there’s no statistically-significant slope to temperatures since 1880, I decided to do an experiment. I took the current record and added longer and longer segments of constant temperature with noise, to simulate a world that stayed at current temperatures for however long I wanted. After adding each decade of temperature, I redid the linear regression, and noted if the slope was statistically significant. I believe I went 1,000 years out and the slope was an obvious and complete mismatch to the data, but its slope was still statistically significant.
Now I *was* just looking at the output of R’s ‘lm’ and not inflating the confidence interval because of autocorrelation, so perhaps was more naive than I should have been. But the point is that once you’ve had an increase, it takes a LONG time for a straight-line slope to fail to be significant.
I think that’s what you’re talking about.
@mwhite
The BBC have published this article on the right day!
Thanks, Bob, for that!
Easy for us bods to pick out climate champion Sir Christopher of Belchley’s iconic 23 year-long billiard-cue he teased us with last time he swung by the Village. Is it my imagination or is the billiard-cue (like other knightly equipment) getting longer each time the yarn is repeated?
Bob, if March also shows anomalous warming over Feb 2013, then I have to protest. It has been a very cold winter and spring across the NH; it even snowed in Tripoli, Libya last week. Has it been particularly hot in the SH? I don’t think so – the sea surface is much greater in the SH and we had record Antarctic ice there last winter and the lingering of nearly a million sq km over climatology at minimum extent. How soon can we tease out March 2013’s figure.
I find it rather odd that GISS went down 0.11 between January and February but Hadcrut4 went up by 0.05. That is a net difference of 0.16. To put this into perspective, 0.16 is what separates first place on Hadcrut4 (0.54) from 14th place (0.383). For now, I will assume that this has nothing to do with trying to make sure the black line in the following does not go below the 95% line, but I will keep my eyes open here:
http://wattsupwiththat.com/2013/03/31/the-mail-on-sunday-takes-on-the-ccc/
Prepare for March data… NH snow cover has been, on average for the month, about 1% greater than normal. Here in Spain it has been the rainiest March since records for this national statistic began in the 1940s. And pretty cold too. Some of our water reservoirs, which had never ever been full since their creation, are now full and evacuating water due to their dangerous levels. Here you can see the graphic of the total ammount of water kept in the reservoirs in Spain. Keep in mind that this comes after an extremely dry 2012, yet we are now 20% above the average, and will soon reach the record levels of 2011 again. What a recovery.
http://www.embalses.net/
The hemispheric split and, perhaps more signficantly, the Europe vs Continetal US of A would be interesting for those who suspect a regional rather than global change is underway (global numbers being mathematically correct but misleading representation of what is happening).
Check sea-cover LOCATION loss for the gross Arctic data, for one example. In February, “open water” is more restricted than you would think by a McKibben-ist.