If We Had Buoy Data From the Past We Would Use That

Much, just about all of David Roses claims in his hit piece on Tom Karl has been walked back, not the least by Rose's source, John Bates.  Among the statements which Bates has disowned and which now must be considered fabrications was the paragraph

Dr Bates said: ‘They had good data from buoys. And they threw it out and “corrected” it by using the bad data from ships. You never change good data to agree with bad, but that’s what they did – so as to make it look as if the sea was warmer.’

but there was actually more both following and afterwards

But Dr Bates said this increase in temperatures was achieved by dubious means. Its key error was an upwards ‘adjustment’ of readings from fixed and floating buoys, which are generally reliable, to bring them into line with readings from a much more doubtful source – water taken in by ships. This, Dr Bates explained, has long been known to be questionable: ships are themselves sources of heat, readings will vary from ship to ship, and the depth of water intake will vary according to how heavily a ship is laden – so affecting temperature readings.

Dr Bates said: ‘They had good data from buoys. And they threw it out and “corrected” it by using the bad data from ships. You never change good data to agree with bad, but that’s what they did – so as to make it look as if the sea was warmer.’

ERSSTv4 ‘adjusted’ buoy readings up by 0.12C. It also ignored data from satellites that measure the temperature of the lower atmosphere, which are also considered reliable. Dr Bates said he gave the paper’s co-authors ‘a hard time’ about this, ‘and they never really justified what they were doing.’

Bunnies can read why this is wrong many places including articles by Kendra Pierre Louis in Popular Science, Zeke Hausfather and lots more.  John Bates can comment on whether it is Rose's fabrication or his.  AFAEK the question has never been put directly to either or answered.

In any case, this has given rise to several including John Bates claiming that NOAA made a dishonest choice when it moved combined the buoy and ship readings by joining the buoy to the ship readings.  In his response to Zeke Hausfather he writes (italics from ZH)

6. ‘They had good data from buoys. And they threw it out […]’ 

v4 actually makes preferential use of buoys over ships (they are weighted almost 7 times in favour) as documented in the ERSSTv4 paper. The assertion that buoy data were thrown away as made in the article is demonstrably incorrect.

Response:  Verbiage used by David Rose is not the key issue here. The issue is the substantial adjustment of the buoy temperatures to match the erroneous ship values, and neglect of data from the Argo buoys.

Well actually it was a direct quote, so Bates is being very slippery here.  But this has given rise to the blathering point that the ship data should have been adjusted to the buoy data.  Much twitting has been wasted on that.  If there is a constant adjustment in either direction it makes no difference in determining the anomaly.  The fact that the size of adjustment is minimally different in v3, v4, v5 and on into the 22nd century is no never mind.

However, there is a significant reason to adjust the buoy data to the ship data.  Peter Thorne has done a service by explaining why NOAA and others update their records.  In his article, Prof. Thorne reproduces a figure from the recent IPCC AR5 report

Changing contribution of different measurement techniques (top panel) and their timeseries relative to the average of all sources at any given time (bottom panel). Note large and systematic offsets between distinct sources that vary through time. Source: IPCC

Ship measurements were the first, actually they go back well before 1920 and buoy measurements only kick in late in the twentieth century.  Earlier (and this would be pretty much anything published before 2000) would only, or massively depend on the ship measurements.  Thus offsetting the buoy to the ship data would cause the least confusion for anybunny looking at older publications. 

Makes sense to do it that way.