The ship-buoy bias correction excuse (HadSST3 and ERSSTv4)

In 2011, the Hadley Centre of the UK Met Office replaced their global sea surface temperature series, HadSST2, with a new one, HadSST3, an upgrade allegedly necessitated by, among other things, the particular ‘discovery’ that the recorded temperature evolution of the global ocean surface had, since about 1979, for one particular reason followed a path that trended artificially low. The official global sea surface temperature data as compiled simply showed too little overall warming. Since 1978-79, that is, during the satellite era.

This is funny, because the Hadley Centre’s own official global SST dataset, HadSST2, already showed an overall warming since the late 70s that was much larger than the other official datasets out there, like ERSST, Reynolds OI and HadISST:

Animation 1.

Note that the new ERSSTv4 series is also included in Anim.1 (red curve), and that it distinctly supports the group of ‘others’: The light blue HadSST2 curve all of a sudden makes a giant upward leap of nearly 0.1K at the 1997-1998 transition (light green vertical line). There is hardly any divergence to be observed between it and the others, however, either before or after this point (save that from ERSSTv4 post 2005; more on that later …). Continue reading

Tamino’s radiosonde problem, Part 1

RSS vs. RATPAC tamino

Figure 1. Original found here:

A good month ago, the perennially unsavoury character calling himself Tamino once again tried to hold up the spotty “global” network of radiosondes (weather balloons) as somehow a better gauge of the progression and trend of tropospheric temperature anomalies over the last 37 years than the satellites, by virtue of being essentially – as he would glibly put it – “thermometers in the sky”.

So his simple take on the glaring “drift” between current surface records and the satellites over the last 10-12 years is this: The surface records are right and the satellites are wrong. Why? Because the surface records agree with the radiosondes while the satellites don’t! The radiosondes implicitly – in his world – representing “Troposphere Truth”.

And so, when your starting premise goes like this: the radiosondes = thermometers in the sky = troposphere truth, then any “drift” observed between them and the satellites (as in Fig.1 above) will – by default – be interpreted by you as a problem with the latter.

To repeat Tamino’s fairly simplistic reasoning, then, in the form of some sort of logical-sounding argument: Surface and satellites don’t agree. Radiosondes and satellites don’t agree. But surface and radiosondes do agree. Which means the latter two are right, their agreement robustly verifying the ‘rightness’ of each. (And also, the radiosondes represent “Troposphere Truth”.) Which leaves the satellites out in the cold …

There is, however, a definite issue to be had with this line of argument.

It doesn’t hold up to scrutiny … Continue reading