More Curiosities about NOAA’s New “Pause Busting” Sea Surface Temperature Dataset
Bob Tisdale / 4 hours ago June 6, 2015
The Night Marine Air Temperature dataset HadNMAT2 from the UKMO is used for bias adjustments of the new NOAA ERSST.v4 “pause-buster” sea surface temperature data over nearly its full term, from 1875 to 2010. But the UKMO HadNMAT2 data are not available online so that the public can easily verify the NOAA ERSST.v4 results. That’s small fish compared to an even bigger problem for NOAA. A preliminary investigation of the UKMO dataset suggests that the HadNMAT2 data do not support NOAA’s claims of no slowdown in global surface warming. In other words, the HadNMAT2 data have a much lower warming rate than the new NOAA “pause buster” ERSST.v4 data since 1998.
INTRODUCTION
In the post NOAA/NCDC’s new ‘pause-buster’ paper: a laughable attempt to create warming by adjusting past data, we discussed the new paper about NOAA’s latest revisions to their global surface temperature dataset. That paper was Karl et al (2015) Possible artifacts of data biases in the recent global surface warming hiatus. The changes to the sea surface temperature component of the new NOAA/NCEI global land+ocean surface temperature dataset were the biggest contributors to claims that the new data show no hiatus or slowdown in global warming since 1998. NOAA’s new extended reconstructed sea surface temperature dataset is called ERSST.v4. Those adjustments and the fact that the oceans cover about 70% of Earth’s surface made the new sea surface temperature data the governing factor in NOAA’s new claims that there was no slowdown in surface warming.One of the oddities of the new NOAA sea surface temperature dataset shown in our earlier post was that the warming rate of the sea surface temperature portion of NOAA’s new data was an outlier since 1998…that it had a much higher warming rate than all other sea surface temperature datasets during the recent slowdown in global surface warming. In other words, there were no other sea surface temperature datasets that supported the high warming trend of the new NOAA data. See Figures 6 through 9 from the earlier post about Karl et al.
What I did not compare to NOAA’s new sea surface temperature dataset in that post was the temperature dataset that served as the reference for bias adjustments over the full term of the data, and that reference dataset was the HadNMAT2 Night Marine Air Temperature data from the UK Met Office. My preliminary investigation reveals that the reference HadNMAT2 data also do not support the excessive warming rate since 1998 of NOAA’s new sea surface temperature data. And that’s a bad sign…a really bad sign.
BACKGROUND
The two papers that present NOAA’s new Extended Reconstructed Sea Surface Temperature dataset ERSST.v4 are (both are paywalled):
We discussed the new NOAA ERSST.v4 data in a few posts last year, including Has NOAA Once Again Tried to Adjust Data to Match Climate Models?
Like their earlier ERSST.v3b dataset, the new ERSST.v4 were bias adjusted by a marine air temperature dataset. But NOAA added a new feature this time through. For the bias adjustments in the earlier ERSST.v3b dataset, NOAA used a night marine air temperature dataset that was part of the ICOADS Release 2.4 (R2.4) to adjust the sea surface temperature for the period of 1875 to 1941. On the other hand, two of the features of the new NOAA ERSST.v4 data was that (1) NOAA used a newer and improved night marine air temperature dataset HadNMAT2 from the UKMO and (2) NOAA extended its use through to 2010. In other words, the HadNMAT2 data were used for bias adjustments for nearly the full term of the new ERSST.v4 data from NOAA. See my Table 1, which is Table 1 from Huang et al. (2014). I’ve highlighted the relevant portion.
Table 1
As they write in Huang et al. (2014) (my boldface):
Firstly, ERSST.v3b does not provide SST bias adjustment after 1941 whereas subsequent analyses (e.g. Thompson et al. 2008) have highlighted potential post-1941 data issues and some newer datasets have addressed these issues (Kennedy et al. 2011; Hirahara et al. 2014). The latest release of Hadley NMAT version 2 (HadNMAT2) from 1856 to 2010 (Kent et al. 2013) provided better quality controlled NMAT, which includes adjustments for increased ship deck height, removal of artifacts, and increased spatial coverage due to added records. These NMAT data are better suited to identifying SST biases in ERSST, and therefore the bias adjustments in ERSST version 4 (ERSST.v4) have been estimated throughout the period of record instead of exclusively to account for pre-1941 biases as in v3b.
Oddly, by using the HadNMAT2 data for bias adjustment, NOAA did not address the post-1941 problem presented in their referenced Thompson et al. (2008), which was the discontinuity in 1945. NOAA seems to have exaggerated that problem in their new ERSST.v4 data. See the earlier post here, under the heading of YOU MAY BE WONDERING…
Considering that the HadNMAT2 data played a key role in the creation of the ERSST.v4 data, it would be logical to compare the new NOAA ERSST.v4 data to the UKMO HadNMAT2 data to see how well those two datasets agree…especially during the global surface warming slowdown period from 1998 to present, which was one of the highlighted periods in Karl et al. (2015) that served as the bases for the odd claims made in that paper.
PROBLEM ONE
The HadNMAT2 data are not yet available to the public online, even though the paper that supports it was published in February 2013. And that paper is Kent et al. (2013) Global analysis of night marine air temperature and its uncertainty since 1880: The HadNMAT2 data set. I emailed the UKMO to determine if the HadNMAT2 data were available somewhere online, and I was advised that they were still trying to decide on the format in which to publish it, the length of time for the decision being unusual for them.
It’s been 2 years. I suspect the UKMO has hesitated in publishing the HadNMAT2 data, because they contradict their HADSST3 data during the period from the early-1940s to the mid-1970s. Recall that in HADSST3 the UKMO eliminated the Thompson et al (2008) “discontinuity” around 1945 and made numerous other adjustments during the 1950s, 60s and 70s. Those changes produced a slight cooling trend from the mid-1940s to the mid-1970s. The HadNMAT2 data have not received those corrections.
The fact that the HadNMAT2 data are not available online, of course, presents problems for the three NOAA papers relating to the ERSST.v4 data: Huang et al. (2015), Liu et al. (2015) and Karl et al. (2015). The results of those papers cannot be verified by the public, because one of the key reference datasets for those three papers has not been published. I wonder if the editors of those publications know that sad fact. I suspect they might be informed in the not-too-distant future.
PROBLEM TWO
The global UKMO HadNMAT2 data are presented in Figure 18 of Kent et al. (2013), alongside their HADSST3 data. See my Figure 1. The global HadNMAT2 data are shown as the black curve. The data in the graph run from 1880 to 2010 (with what appears to be a slight downturn in 2011 from an incomplete year of data).
Figure 1
(A larger version of the graph is here.)
While there is software available that will extract data from graphs, I prefer to use the x-y coordinates of MS Paint to replicate the data. My results for the HadNMAT2 data for the period of 1998 to 2010 are shown in Figure 2, compared to the global ERSST.v4 data used by Karl et al. (2015) for their claims of “no hiatus”.
Figure 2
Of course, Karl et al. presented their trends for the period of 1998 to 2012 and from 2000 to 2014. But I know of no source of the HadNMAT2 data for the years of 2011 to 2014. So this is preliminary comparison.
These preliminary results strongly suggest that even the (HadNMAT2) data used as the reference for bias adjustments in the new NOAA sea surface temperature dataset (ERSST.v4) do not support that ERSST.v4 data…or the claims in Karl et al (2015) of no slowdown in global surface warming.
Not too curiously, as far as I can tell, NOAA failed to present those differences in their papers. While NOAA may now try to justify those differences in the short-term warming rates of ERSST.v4 and HadNMAT2, they look very awkward, and any excuses NOAA gives now will simply be viewed as that…excuses.
CLOSING
As noted earlier, the preliminary investigation that shows the HadNMAT2 data do not support the claims of no hiatus is a bad sign for the results of Karl et al. (2015), a very bad sign.
I suspect that the editors of the journals that published the three ERSST.v4-based papers (Huang et al. (2015), Liu et al. (2015) and Karl et al. (2015)) will soon be informed of this problem as well.
When the HadNMAT2 data are finally published online by the UKMO, that reference data for the NOAA ERSST.v4 data will very likely put NOAA and the publishers of the Huang et al. (2015), Liu et al. (2015) and Karl et al. (2015) papers in very awkward positions. Time will tell.
wattsupwiththat.com
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Mike says:
June 6, 2015 at 7:38 am
Good work Bob, the key thing here is that the NMAT has not even been released yet.
They are trying to rewrite the global temp record, with heavy policy implications, based on a dataset that the owners do not even have enough confidence in to make public.
This will put pressure on Hadley to release the data, then we can have proper look at what kind of voodoo science has been done by Karl.
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mpaul says:
June 6, 2015 at 7:49 am
If your post-modern “scientific breakthrough” is to simply find a transformation that takes data set A and converts it to a desired data set B, then it really doesn’t matter what you use for data set A. All that matters is that you have enough degrees of freedom to produce a nearly infinite set of possible transformations and that the values of data set B have a slight range (if the values of data set B needed to be exact, then the carnival trick gets a bit more difficult). So if you point out that Climategate Co-conspirator Karl used the wrong starting data, his rejoinder will simply be that he discovered an error in his transformation and, once corrected, the result will be a new data set that is in the acceptable range of the desired outcome. I suspect you could give CCK any data set of equivalent cardinality and he could produce a bankable result using his breakthrough method.
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mpaul says:
June 6, 2015 at 8:00 am
AdjustGate?
cheshirered says:
June 6, 2015 at 8:46 am
Fiddlegate
Datagate
Noaagate
Pausegate
Take your pick.
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Peter Azlac says:
June 6, 2015 at 8:09 am
“The HadNMAT2 data are not yet available to the public online, even though the paper that supports it was published in February 2013. And that paper is Kent et al. (2013) Global analysis of night marine air temperature and its uncertainty since 1880: The HadNMAT2 data set.”
The major part of the historical sea (sub)surface temperature data comes from ships with all the problems involved that have been discussed in the various criticisms or the Karl et al paper. However, one point I have not seen brought out enough is how concentrated the measurements are on limited areas of the oceans. This can be seen from a comparison of shipping maps from 1900 with the present:
Present: http://upload.wikimedia.org/wikipedia/commons/3/39/Shipping_routes_red_black.png
1900: http://www.knmi.nl/cliwoc/images/all_ships0.jpg
These maps show that in 1900 most shipping was in the Atlantic, Indian oceans and around Indonesia but later in the century this expanded considerably to cover the Northern Pacific. Given the differences in heating of the Indian and S Atlantic oceans to the N Pacific and the sparse coverage of the Southern oceans the idea that any SST series can be based on temperature data from shipping is a joke. Especially given that the oceans cover 70+ percent of the Earth’s surface and take in 80+ percent of solar energy, mainly in the areas that are sparsely sampled by shipping in 1900 and now.
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