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.

Lies, Damned Lies, and Wiggly Lines

Visitors to this blog may wonder what my underlying motives and views are. I have only one motive; telling the truth. My views vary with time - anyone whose views on any subject don't vary, even a little with time, have a fixed mindset, which is not a good thing. My views change as I learn, and they change as I get a better viewpoint on the "bigger picture" . Anyone who tells you, or leads you to believe, that they know "pretty much all there is to know" on any subject whatever apart from the size of Algore's bank balance, is either a liar or an egotist, or both.

I chose to study the aspects of sea-level change some years ago. One reason was that I perceived that very few people, whether bloggers, their respondents, columnists or news reporters (whatever their title), know anything much at all on the subject. Many think it's pretty straightforward; just measuring the height of the sea at any one point, and plotting a few graphs and trends. How little they know.

Another reason was that I thought that even with a little knowledge, I might be able to shed a little light in an area of low understanding - which shows what little I knew. Sea level varies all around the globe; it varies from day to day, month to month, year to year, decadally and on longer time scales, and it varies from place to place. It varies for a variety of reasons; a change in the mass of water in the oceans, a change in the volume of that mass, with ocean basin volume due to tectonic movements, with temperature, wind strength, wind direction, barometric pressure and ocean currents, and even local gravity. If you think that changes in weather and climate are complex, but changes in sea level are not, think again.

Hurricane Sandy was a child of the ocean, and not of the atmosphere. Some climate scientists and climate modellers appear (and there's plenty of evidence to support my view) to think that the atmosphere controls the climate, and the climate modifies the oceans. How wrong they all are.

A seemingly trivial yet important fact is that the tides generated by the Moon, modified by the Sun, shift more water from place to place over a single tidal cycle of just over 12 hours than all the ocean currents combined do in a year. That tidal  shifting is an oscillation of course, but because the globe isn't covered completely in water, the continents and large islands "get in the way", and the tides modify currents at continental margins quite significantly, creating "eddies" which disrupt, spread, and even temporarily reverse the flow.

The oceans cover about 2/3 of the Earth's surface which gets most sunlight. The oceans also absorb more of the Sun's energy than does the land, and they absorb it to a far greater depth. The land surface warms and conducts to just a few centimetres depth during the daytime. The oceans absorbs visible light and short-wave infrared (about 50% of incident solar radiation, a fact known to few it seems), to a depth of tens of metres. The oceans have a heat capacity thousands of times that of the atmosphere. Physicist Lord Rutherford is reported to have said, in an argument about whether electrons orbited the relatively massive atomic nucleus, or vice versa, "When you've got a flea on an elephant, it's the flea that jumps". The oceans are the elephant, and the atmosphere is the flea.

Studying all aspects of the physics of the oceans is the key to understanding weather and climate. To ignore, marginalise or trivialise the role of the oceans is indeed to "ignore the elephant in the room". The oceans drive and control all the climate oscillations from ENSO to the AMO. Note that climate scientists and modellers study "atmospheric sciences". Draw your own conclusions from that - I already have.

Where is all this leading? Why my post title? I could show you 20 charts for tide gauges which show alarmingly high rates of sea-level rise, to prove something catastrophic is just over the horizon (apt metaphor?). I do not. I could show you 20 charts which show virtually no change for half-a-century, "nothing much is happening", yet I do not. I could show you 20 charts which show a fairly steady decrease over a century, to prove that "sea-level is not rising", and I do not. None of these collections would illustrate the truth, though many people would have you believe that their little collection does. Ignore them - their little collection of wiggly lines and "revealing" trends are only a "cherry-picked" and biased version of the truth; there's a very thin line between bias and lies.

Those of whatever persuasion who cherry-pick are guilty of misrepresentation at best, lying at worst. Those who cherry-pick should remember that their "evidence" may reveal more about them than their "hypothesis" does about the true situation. That their evidence may contain at least one "hidden message" which is visible to anyone who has a truly sceptical eye and a little knowledge, and which may be used to disprove their claims. Those who cherry-pick should remember that they may choke on the stones.

The Ups and Downs of Sea-level Recording

Google sometimes comes up with odd results - not the wrong results I hasten to add, but something unexpected, something novel, something revealing. Anyway, one result was a pdf which referred to Anthony Watts (Wattsupwiththat) as a "sea level expert", with a link to a WUWT post which contains the following:

IMHO The idea that a dock (or piling) is a long term stable measurement platform is simply ludicrous. Piles sink, structures decay, boats whack them, pounding wave action loosens their grip. One feature missing from all these old style tide gauges is any way to reference the long term level of the gauge itself. In the era of GPS we can start doing this, but in the years past, how much is from simple sinking of the pilings over time? When you are looking for millimeters per year, such things become significant.

Anthony Watts would hardly describe himself as a "sea level expert", but that's by-the-by. The post was discussing sea-level past and present in the Maldives, and curiously for such a topic, presented no sea-level data whatsoever. However it's Anthony's statement "One feature missing from all these old style tide gauges is any way to reference the long term level of the gauge itself" which I'm concerned with here. I could criticise him for that statement, written in ignorance, but I'll just ask the question "Can you think of any method of establishing the level of land surface, buildings, or anything attached to the land?". if you can't, go to the bottom of the class. If you thought "surveying" or it's more technical term "levelling" you go to the top. There is indeed a "way to reference the long term level of the gauge itself". Here's a photograph of a  surveyor engaged in that very process next to the Funafuti, Tuvalu SEAFRAME station in January, 2009:

Source: SOPAC

He's using a modern state-of-the-art instrument termed a "total station". The model he's using is one of the best. It can measure to 0.5 arc-seconds in elevation and traverse - that's 1/7200 of a degree, and to 1 in 1,000,000 in line-of-sight distance, which is 1 mm in 1000 metres. The latter is achieved using laser-ranging, also used to continuously monitor the height of the instrument above the benchmark below to 0.1 mm.

I can tell you the make, model and serial number of the instrument he's using (LEICA Total Station Model TCA1800, S/N 424936), his name (Andrick Lal) and the organisation he still works for - SOPAC (Applied Geosciences Division). He was there in 2009 with Nick Brown, a  surveyor for Geoscience Australia. The details of the survey (as for all others) are published in reports on the GA ftp server and many are referenced on the GA website.

They were actually establishing the exact location and height of the tide-gauge benchmark (TGBM) wrt to the benchmarks for the CGPS (continuous GPS) pillar which is located some 2.5 km away from the gauge, but Australia's National Tidal Centre surveyors use identical equipment and techniques every year or two - this is the only Tuvalu survey I've been able to find photos for. There's a chain of an additional 12 BMs between the tide-gauge BM and the CGPS pillar BM - 14 in all.
Levelling the Funafuti CGPS pillar:

Source: SOPAC

I read somewhere that these surveys always seem to take longer on the Pacific islands than elsewhere - I can't imagine why. can you?. BTW levelling doesn't involve any adjustment - it's a measuring exercise. Some claim that CGPS is used to "automatically adjust" gauges. Nothing could be further from the truth - those that make such claims generally include a diagram of a SEAFRAME station which shows the CGPS station firmly on land. Apart from that it's not practical to do so. Few are aware of the "crustal tide" caused by the Moon, which pulls the Earth's crust up and down, synchronised with the ocean tides. At the sites of the  Funafuti stations shown above, it amounts to around 10-20 cm at peak; any automatic adjustment would lower the gauge as the ocean tide rises, and vice versa.

The point I'm making is that this process is carried out regularly and with great care and the results made available on the 'net. Not all gauge sites worldwide are levelled as frequently as those in the South Pacific Sea Level Monitoring Programme however. Most aren't the focus of attention that these islands have become. Many are relatively stable and need less frequent checking. Note that even at other sites with CGPS stations on both the gauge and on land, regular levelling takes place. The benchmark which marks the datum (reference level) for measurements is referred to as TGZ - tide gauge zero. Sometimes the nearest benchmark is above lowest water and a fixed positive offset is added to the gauge readings to give an always-positive reading - from a "virtual benchmark" in fact.

Here's a picture (looking SE) of another gauge which is relevant to the secondary theme of this post. It's the Male-B station in the Maldives, northern Indian Ocean.The gauge, or rather gauges, are on Hulule island where the airport is situated, adjacent to Malé itself.

Source: SONEL

Source: University of Hawaii Sea Level Center

The people in the background on the right aren't back-packers but are part of a University of Hawaii team, on-site to check and maintain the equipment. Looks like a helluva job to me. I don't know how they can stand all that sunshine and sea air.
I include the following description because some people (no names, no pack drill) like to give the impression that sea-level data is recorded by a man with a marked stick and a clipboard, when he can be bothered so to do. The Malé station currently has three independent gauges; a float gauge with the small dome atop on the left, a bubbler gauge with the box on top, and a radar gauge on the black bracket over the water. The two large vertical "pipes" are "stilling wells". They aren't simply open at the bottom, but have holes near the lower ends which restrict the rapid influx or efflux of water (hence "stilling") to eliminate the effect of waves, the wash of a passing boat, or a diving horse, perhaps.

The potentiometer at the top of the float gauge. The toothed metal belt carries the float.

Looking down the float gauge stilling-well; the float is centre-right at the water surface.
Source (both photos): University of Hawaii Sea Level Center

A bubbler gauge releases nitrogen gas into the water near the bottom of the stilling well. At the depth of the release valve the pressure varies with the depth of the water above, and a pressure recorder monitors the pressure of the gas as it's released. Pressure varies linearly with depth so it's easy to convert the pressure readings into an accurate depth. A temperature sensor records water temperature so consequent changes in water density and gas pressure can be allowed for.

The workings of the float gauge, and the radar gauge over the water should be fairly obvious. The dome on the central pillar contains the receiver and aerial for the CGPS (continuous GPS) station which constantly records the E-W, N-S and vertical coordinates (position) of the station. Benchmarks at the station, and three sites around up to a kilometre away provide for levelling by surveying instruments. The station collects data and transmits it to a satellite at hourly intervals and it's been recording since 1990. There's another GPS (& laser telemetry) station located some distance to the NE which is part of the DORIS system, a worldwide network used for precise determination of the JASON-1 satellite's orbit. Here's what Male-B recorded between 1990 and 2010. Bear in mind that the CGPS station recorded some millimetre-sized ups-and-downs over the last decade but they averaged out to just -0.1 mm/year fall.

Data source: PSMSL

To the south, at Gan on Addu Atoll, is another float-type gauge, with a slightly longer record but which shows a similar 13-month profile and annual trend.

Data source: PSMSL

I've never seen these charts (or any earlier version from any source) shown on any sceptical blogs. Nils-Axel Mörner has written screeds on the Maldives, but I've never seen them shown therein either. Do they show something inconvenient? What, precisely, is wrong with the unvarnished truth? Mörner has referred to them however in a 2004 paper titled "New perspectives for the future of the Maldives". I don't know when he visited the Maldives, as rather curiously, the paper doesn't give any dates.  He states in his conclusion (multiple authors, but they're his words, I'm sure)

Tide gauge data have been cited in support of an on-going rise of mean sea level (Singh et al., 2001). Tide gauge records, however, do not provide simple and straight-forward measures of regional eustatic sea level. They are often (not to say usually) dominated by the effects of local compaction and local loading subsidence. With this perspective, our multiple mor-phological and sedimentological records appear more reliable and conclusive. Besides, satellite altimetry does not record any significant rise in global sea level in the last decades (Mörner, 2003a, Fig. 2). In order fully to investigate the situation, however, available tide gauge records, now extending from 1990 to 2002, were re-examined. This reveals a total absence of any rising secular trend (Mörner, 2003b).

He's saying that tide gauge records don't provide reliable indications of sea level trends, but uses them to prove a point he's making, because he claims that what they show conveniently proves that point? There's a word (several words in fact) for that kind of thing. It's also difficult to understand how 13 to 14-year-span gauge records could possibly reveal anything about the presence or absence of a "secular trend", as in this context "secular" means long-term. He also says "extending from 1990" - the Gan record starts in 1988. Incidentally, the reference "Mörner, 2003b" was never published. There's a whole story here but it's for a future post.

I take issue with his statement that "Tide gauge records, however, do not provide simple and straight-forward measures of regional eustatic sea level. They are often (not to say usually) dominated by the effects of local compaction and local loading subsidence". They are not so "dominated", but many are affected. Many others are affected by just the opposite, where the land is rising, and sea-level rise is understated, something he fails to mention here. His term "regional eustatic sea level" is confusing and ambiguous  It's a term he's proud to have invented - eustatic means worldwide or global so he's effectively using the term "regional global sea level". It's worse than confusing and ambiguous. It's meaningless, a contradiction in terms.

In my opinion, and in the opinion of others too, the worldwide tide-gauge network provides a more reliable source of environmental data than do thermometers in weather stations. Tide gauges have inherent sources of error, they're subject to vertical movement caused by subsidence or rebound of their mountings (piers, jetties, etc) and the land or seabed beneath, but those errors can be and are identified, quantified, and allowed for by adjustment of the data. What's more. such adjustments are usually very small and full details are published on the 'net. Many gauge stations have multiple gauges as at Malé, and an increasing number use CGPS to monitor stability and record the slightest movement. Most transmit their data at regular intervals by telephone line or satellite link, so any malfunction is soon spotted. All have a linear and uniform response, unlike temperature sensors whose non-linear response has to be allowed for by the recording circuitry, and they're not subject to sensor drift which may occur for some time before it's identified. There's no equivalent of UHI either, and so far no organisation has been able to get their grubby hands on the data and homogenise it or apply suspicious "adjustments".