Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Politics : The Trump Presidency -- Ignore unavailable to you. Want to Upgrade?

To: Sam who wrote (9676)	2/5/2017 9:11:30 PM
From: Wharf Rat	Respond to of 354335

more on Bates On the Mail on Sunday article on Karl et al., 2015 There is an "interesting" piece (use of quotes intentional) in the Mail on Sunday today around the Karl et al., 2015 Science paper. There are a couple of relevant pieces arising from Victor Venema and Zeke Hausfather already available which cover most of the science aspects and are worth a read. I'm adding some thoughts because I worked for three and a bit years in the NOAA group responsible in the build-up to the Karl et al. paper (although I had left prior to that paper's preparation and publication). I have been involved in and am a co-author upon all relevant underlying papers to Karl et al., 2015. The 'whistle blower' is John Bates who was not involved in any aspect of the work. NOAA's process is very stove-piped such that beyond seminars there is little dissemination of information across groups. John Bates never participated in any of the numerous technical meetings on the land or marine data I have participated in at NOAA NCEI either in person or remotely. This shows in his reputed (I am taking the journalist at their word that these are directly attributable quotes) mis-representation of the processes that actually occured. In some cases these mis-representations are publically verifiable. I will go through a small selection of these in the order they appear in the piece: 1. 'Insisting on decisions and scientific choices that maximised warming and minised documentation' Dr. Tom Karl was not personally involved at any stage of ERSSTv4 development, the ISTI databank development or the work on GHCN algorithm during my time at NOAA NCEI. At no point was any pressure bought to bear to make any scientific or technical choices. It was insisted that best practices be followed throughout. The GHCN homogenisation algorithm is fully available to the public and bug fixes documented. The ISTI databank has been led by NOAA NCEI but involved the work of many international scientists. The databank involves full provenance of all data and all processes and code are fully documented. The paper describing the databank was held by the journal for almost a year (accepted October 2013, published September 2014) to allow the additional NOAA internal review processes to complete. The ERSSTv4 analysis also has been published in no fewer than three papers. It also went through internal review and approval processes including a public beta release prior to its release which occurred prior to Karl et al., 2015. 2. 'NOAA has now decided the sea dataset will have to be replaced and revised just 18 months after it was issued, because it used unreliable methods which overstated the speed of warming' While a new version of ERSST is forthcoming the reasoning is incorrect here. The new version arises because NOAA and all other centres looking at SST records are continuously looking to develop and refine their datasets. The ERSSTv4 development completed in 2013 so the new version reflects over 3 years of continued development and refinement. All datasets I have ever worked upon have undergone version increments. Measuring in the environment is a tough proposition - its not a repeatable lab experiment - and measurements were never made for climate. It is important that we continue to strive for better understanding and the best possible analyses of the imperfect measurements. That means being open to new, improved, analyses. The ERSSTv4 analysis was a demonstrable improvement on the prior version and the same shall be true in going to the next version once it also has cleared both peer-review and the NOAA internal process review checks (as its predecessor did). 3. 'The land temperature dataset used by the study was afflicted by devestating bugs in its software that rendered its findings unstable' (also returned to later in the piece to which same response applies) The land data homogenisation software is publically available (although I understand a refactored and more user friendly version shall appear with GHCNv4) and all known bugs have been identified and their impacts documented. There is a degree of flutter in daily updates. But this does not arise from software issues (running the software multiple times on a static data source on the same computer yields bit repeatability). Rather it reflects the impacts of data additions as the algorithm homogenises all stations to look like the most recent segment. The PHA algorithm has been used by several other groups outside NOAA who did not find any devestating bugs. Any bugs reported during my time at NOAA were investigated, fixed and their impacts reported. 4. 'The paper relied on a preliminary alpha version of the data which was never approved or verified' The land data of Karl et al., 2015 relied upon the published and internally process verified ISTI databank holdings and the published, and publically assessable homogenisation algorithm application thereto. This provenance satisfied both Science and the reviewers of Karl et al. It applied a known method (used operationally) to a known set of improved data holdings (published and approved). 5. [the SST increase] 'was achieved by dubious means' The fact that SST measurements from ships and buoys disagree with buoys cooler on average is well established in the literature. See IPCC AR5 WG1 Chapter 2 SST section for a selection of references by a range of groups all confirming this finding. ERSSTv4 is an anomaly product. What matters for an anomaly product is relative homogeneity of sources and not absolute precision. Whether the ships are matched to buoys or buoys matched to ships will not affect the trend. What will affect the trend is doing so (v4) or not (v3b). It would be perverse to know of a data issue and not correct for it in constructing a long-term climate data record. 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. 7. 'they had used a 'highly experimental early run' of a programme that tried to combine two previously seperate sets of records' Karl et al used as the land basis the ISTI databank. This databank combined in excess of 50 unique underlying sources into an amalgamated set of holdings. The code used to perform the merge was publically available, the method published, and internally approved. This statement therefore is demonstrably false. There are many other aspects of the piece that I disagree with. Having worked with the NOAA NCEI team involved in land and SST data analysis I can only say that the accusations in the piece do not square one iota with the robust integrity I see in the work and discussions that I have been involved in with them for over a decade. icarus-maynooth.blogspot.com.au This is the blog of the Irish Climate Analysis and Research Units hosted by the Department of Geography at Maynooth University. It is primarily used to highlight newly published research and activities that may be of general interest