Tuesday, 12 February 2013

Nils-Axel Mörner and his Cuxhaven Curve

In a previous post, I closely examined Nils-Axel Mörner's claims about sea-level in the North Sea, highlighting his "curve" which was based on a flawed "modelling" of the record for Cuxhaven on the North Sea coast of Germany,  I posed a question about satellite altimetry; "Does anyone really think that altimetry maps would be produced that could be easily refuted by data from a few tide gauges?". I now pose another; why would anyone produce a curve purported to represent North Sea sea-level changes over more than a century and a half, when reference to tide gauge records, even that for the single station used would prove it to be totally incorrect over its latter half? A certain Stockholm professor (retired) would. A certain Stockholm professor (retired) has.  Here's his curve again:

The Cuxhaven Curve, with a guest appearance by Amsterdam (d. 1930, R.I.P.)

It doesn't show "eustatic sea level". The term "eustatic" refers to a global change in ocean volume. The North Sea is not global, and Cuxhaven, used to produce the curve, ain't the North Sea. The abstract of his 1973 paper Eustatic changes during the last 300 years, which immediately contradicted the title (my bold), states
Tide gauges in rising and subsiding areas show a major change in the shore-level displacement at about A.D. 1840, caused by the onset of a rapid eustatic rise. Comparisons between information from Amsterdam, Stockholm and Warnemünde provide material for the reconstruction of the eustatic changes during the last 290 years. Relative uplift data from the Swedish west coast, corrected according to the eustatic curve established here, give the same location of the isostatic zero isobase as does the geological material for the last 7,000 years. The eustatic changes closely follow climatic changes. A rapid eustatic rise started about 1840, slowed down about 1930 and ended about 1950. Knowing the eustatic factor, the isostatic (or tectonic) factor is calculated for different areas of importance in the discussion of Holocene eustatic sea-level changes.
It's impossible to determine eustatic changes from a few tide-gauges and over a relatively small region. There's no way to separate the eustatic component from the local true sea-level change. Just to establish that local or regional rate, data from a number of gauges is needed and over the entire area of study. A couple in the Baltic and one truncated series on the North sea coast just ain't gonna cut it, but the "world's leading sea-level expert" has convinced himself he can.

 Warnemünde? It's in the southern Baltic on the German north coast. How does its record bear out the statement " A rapid eustatic rise started about 1840, slowed down about 1930 and ended about 1950"?

Warnemünde 2, GER 1855-2011                                                            Data Source: PSMSL

There's a little downward dip from 1930 to 1942 then it's "onward and upward", business as usual, and no sign of "ended about 1950". If Mörner had stuck to his previous theme of "No alarming sea-level rise", which I agree with, I'd have simply ignored his flawed methodology, blatant cherry-picking, gross over-simplification and misrepresentation. I'd have ignored him altogether. He'd have been singing the right song, and despite singing the wrong notes in the wrong order, and some very dubious words, it still would have been the right song. However I can't stand aside and ignore what is clearly a fabrication.

What about Stockholm, which I'm sure has a famous university, which must have produced many notable alumni? The situation there isn't clear cut at first.

Stockholm, SWE 1889-2011                                                                   Data source: PSMSL
Stockholm, and the gauge site along with it of course, is uplifting (post-glacial rebound) at almost 5 mm/year. However, GPS stations abound in Europe, and Scandinavia particularly. That for Stockholm shows 4.9 mm/year uplift (see chart below), and it's an easy matter to adjust the record upward by that amount.
Fig. 3 Interpolated surface of crustal uplift rates (in mm/y) according to BIFROST permanent GPS network data (Lidberg et al. 2007). From Postglacial rebound and relative sea level changes in the Baltic Sea since the Litorina transgression, Rosentau et al., BALTICA Volume 25 Number 2 December 2012 : 113–120
Stockholm has the "4.9" figure against it, second purple circle along the transect line from A at the bottom left (click to enlarge, as with all images which show that message on mouseover). Here's the annual average plot.

Stockholm, SWE 1889-2011, adjusted up by 4.9 mm/year                  Data source: PSMSL
This doesn't follow the Mörner model either. There's a big dip 1926-1948, then a slow decline (almost horizontal) to 1978, then an irregular upward trend to 2011. I could show the record prior to 1889, from the older gauges, but it's irrelevant here.

Gauges? There have been several; the first was a simple scale cut in the seaward wall of the Sluice, the sea-lock between the Baltic and lake Mälaren, marked in feet and inches (pre-metric, and Swedish feet). this was superseded by several wooden posts also marked in feet and inches, which had to occasionally be moved, vertically or laterally with construction work in progress, and replaced as they rotted. This shifting about created a veritable jigsaw puzzle for future researchers, who had to spot discontinuities in the records and consult ancient documents in order to create an (almost) continuous record up to the installation of a mareograph (float-gauge with pen recorder, similar to a barograph in operation) in 1889 at yet another site. That site is where the current (modern) gauge is located. (ref, The Changing Level of the Baltic Sea during 300 Years: A Clue to Understanding the Earth, Martin Ekman, 2009)

Mörner has said in several articles
Tide gauges were installed at harbor constructions to measure changes in tidal level and long-term sea-level changes. The Amsterdam tide gauge is the oldest, installed in 1682; the Stockholm tide gauge is the second-oldest, installed in 1724/1774; and the Liverpool tide gauge is the third-oldest, installed in 1768. Most tide gauges are installed on unstable harbor constructions or landing piers. Therefore, records from tide gauges are bound to exaggerate sea-level rise.
None of those statements is strictly true. In the 17th/18th centuries, no-one was worried about sea-level rise, indeed it was generally falling. Falling sea-level is a headache for port operators as it means expensive dredging may be necessary. Saying any tide-gauge is "the oldest" is rather like saying "my broom is 100 years old", when it's had 12 heads and 6 handles. The first Amsterdam tide gauge was the oldest; a simple wooden scale (in feet and inches, but Dutch feet!) it was superseded by several more as the Dutch built and improved canals and locks in and around Amsterdam and its port. I've outlined the history of the Stockholm gauges above. The Liverpool tide gauge was installed in 1991, preceded by a number of different types, and in different locations, the first being a wooden scale graduated in Imperial feet and inches. As Michael Caine would say "Not many people know that".

Most tide gauges were and still are are being installed on piers and jetties - it's where they're needed most, and they have to be installed over reasonably deep water where the lowest tide won't uncover the gauge. Anyone who thinks that these constructions are inherently unstable ought to consider that they were built to facilitate trade. No-one builds an expensive pier or jetty if poor construction would mean a costly interruption of that trade caused by equally costly extensive repairs or rebuilding. Records from tide-gauges are not "bound to exaggerate sea-level rise"; many do, but we've seen one example from Stockholm (do I know of someone who lives there?), and there are many more in the Baltic, Norway, northern UK, Canada, Alaska, China, Russia, and the Southern Ocean that show just the opposite, due to post-glacial rebound, and many more because of tectonic movement.

Mörner has to discredit satellite altimetry (despite having used it in several papers - will he withdraw them?), tide-gauges (but uses records without comment when it suits him), other scientists and their papers, and accepted and proven principles of steric (thermal, temperature-related) ocean expansion, because all of these refute his claims. Hence his silly stunt with Willy Soon, who should know better, claiming that horse-jumping, and the attendant crowds, had disturbed the Atlantic City pier and therefore the gauge installed there. Even if they were right, horse-jumping never caught on anywhere else in the world, and a 1904 storm that destroyed the seaward third of the massive "Steel Pier" left the gauge installation half-way along intact and virtually undisturbed. A claimed disturbance to one gauge out of almost 2,000 worldwide doth not an hypothesis prove, but one publicity-seeking stunt can reveal a lot about those who try it on.

That Washington Post piece was titled "SOON AND MORNER: Sea-level rise data based on shoddy science" and ends "Not surprisingly, objective sea level research should be based on observational facts in nature itself and not on computer models". Mörner considers other scientists who analyse sea-level data to be "modelling on the computers". I've shown he should have done a bit more of what he misleadingly calls "modelling" and "shoddy science" himself. By not doing so, he's making a fool of himself, and producing what is really "shoddy science"; not science at all in fact. Any scientist, and I count myself an amateur scientist as much as a blogger, should test their own hypothesis to destruction; look for evidence to disprove it as much, if not more, than evidence to support it. The "null hypothesis" should be a starting point. Mörner didn't look beyond a few gauges, and he didn't even look beyond 2000, calling that "current". He has an axe to grind, and the faithful should realise that he'll play any card, and from more than one deck, to grind it. He has shown no objectivity whatsoever - in anyone that's bad, in a scientist it's the road to advocacy and not the path of science.

I've had a NW Europe reference page in preparation for a while, and I'll get my act together and post it soon. It'll have rather more than a few charts for all countries bordering the Nort Sea and English channel, and several for the Baltic too.

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