Guest Post by Willis Eschenbach
Nerem and Fasullo have a new paper called OBSERVATIONS OF THE RATE AND ACCELERATION OF GLOBAL MEAN SEA LEVEL CHANGE, available here. In it, we find the following statement:
Both tide gauge sea level reconstructions and satellite altimetry show that the current rate of global mean sea level change is about 3 mm yr–1, and both show that this rate is accelerating.
So the claim is that tide gauges show acceleration. Let’s start with a look at the Church and White (hereinafter C&W) estimate of sea level from tide gauges around the world, which is the one used in the Nerem and Fasullo paper. The C&W paper is here.
Figure 1. Church and White sea level rise estimate.
Not real scary …
However, there is an oddity. Let’s take a closer look at the C&W sea level estimate shown in Figure 1.
Figure 2. As in Figure 1, but with a different scale.
Now, when I looked at that, the curious part to me was the change in the recent trend. For the last quarter century, we’ve had satellite sea level data, which began in 1993. In the past, the trend of the satellite data (1993 – 2013, 2.8 ± .16 mm/year, or about an eighth of an inch per year) has been almost double the overall trend of the tide gauges (1.6 ± 0.14 mm/year).
But in this most recent C&W estimate, the recent tide gauge trend is much larger. How much larger? Well … a lot. In fact, the recent C&W estimate is greater than the satellite estimate for the overlap period …
Figure 3. As in Figure 2, showing trends for the 21-year periods before and during the satellite era.
Why the increase in trend? Well, since 1993 they’ve mixed satellite data in with the tide gauge data.
To combine the tide gauge and satellite datasets, … Church and White (2011) and Ray and Douglas (2011) use empirical orthogonal functions of the satellite data with principal components derived from the tide gauge records. Church and White analyze changes in sea level over time, enabling them to use many tide gauges, some with short records, without needing to relate the absolute level of different tide gauges. SOURCE
But is this approach justified? I mean, did the tide gauge data itself go up during that time, so that it would be reasonable to use satellite data to refine the results?
Now, that is a tough question to answer, because the tide gauge data is sparse spatially and temporally, and it is also affected by vertical land motion. But you know me … I’m a data guy. So I went and got the full set of 1,512 tide gauge records from the Permanent Service For Mean Sea Level. In passing let me say that I don’t think they could make it harder to collect the data. It is in 1,512 separate files. Not only that, but the so-called catalog looks like this:
Figure 4. PSMSL Catalog. It is great fun to convert this to a simple computer file … but I digress.
To highlight some of the problems with converting tide-gauge data to global sea level data, here are ten typical records in the dataset:
Figure 5. Typical tide gauge records.
I’m sure you can see the difficulties. Some places the land is steadily rising from post-glacial rebound, and it’s rising so fast that the sea levels are actually sinking relative to the land. In other places, the land is sinking due to subsidence and groundwater extraction. Many records are short and have gaps. Generally, it’s a mess.
So … here was my thought about how to get around these issues: You’ll note in Figure 3 above that the increase in trend between the 21 years before the satellite era and the 21-year overlap during the satellite era was 2.1 ± 0.5 mm per year. And while the trends in the tide gauges are all over the place … I can look at the difference in the trends for each individual dataset over the same period. This gets rid of the problem of vertical land movement, which is constant over such a geologically short time period. So here was my procedure.
First, from the 1,512 tide gauge records in the PSMSL dataset, I selected all the records that contained 90% data over the 21 year period before the satellite era and also had 90% data over the succeeding 21 year period during the satellite era. This left me with 258 tide gauge datasets with coverage over the full 42-year period.
Next, I calculated the trend for each of these datasets for the period before and during the satellite era.
Then, for each tide station, I subtracted the pre-satellite trend from the satellite trend. And finally, I got the median and the uncertainty of those 258 trend differences. Figure 6 shows a graphic of those results.
Figure 6. Comparison between the values and the errors of the difference between the 21-year trend before the 1993 start of the satellite record, and the succeeding 21-year trend from 1993 to the end of the Church and White records. The C&W trends are shown in Figure 3 above.
Since the error bars (orange and red) do not overlap, we can say that the C&W estimate does NOT agree with the tide gauge data. And that, of course, means that it has been artificially increased by cross-pollution with satellite data.
Let me close by saying that I think that it is very bad scientific practice to splice together a terrestrial and a satellite record unless they agree well during the period of overlap. In this case, they disagree greatly over the period of record. For the detrended values over the period of overlap (1993-2013), the R^2 value is 0.01 and the P-value is 0.37 … in other words, there is absolutely no significant correlation between the satellite data and the C&W estimate.
And this makes it very likely that Church and White are manufacturing sea level acceleration where none exists … bad scientists, no cookies.
Finally, at the end of my research into this, I find that I’m not the only one to notice the discrepancy …
Figure 7. Different results for the satellite era depending on whether or not the satellite data is illegitimately spliced into the tide gauge records. SOURCE
My best to everyone. Here I’m staying indoors on a rainy Sunday, watching American football and researching the vagaries of sea level …
w.
As Always: I politely request that when you comment, you quote the exact words you are discussing, to avoid misunderstandings.
Data: So that others won’t have the hassles I had extracting and collating the data, I’ve put the full PSMSL dataset as a single comma-separated values (CSV) file here, and the PSMSL catalog here.
Data 2 :Commenter Bear was unable to download the files and suggested I change the end of the link. New links to PSMSL file here, and the PSMSL catalog here.
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It is inherently unlikely that any long-running trend in any time series would JUMP by approximately 100% at any given time, for no reason that is detectable by competent scientists. If that jump happened to coincide temporally with the advent of a competing time series, that synchronicity would be strong circumstantial evidence that the first dataset had somehow been polluted by the second.
If the jump were to coincide BOTH temporally AND spatially (ie numerically) with the arrival of the second dataset, then that would create a presumption that cross-pollution had occurred. In the absence of evidence to rebut that presumption, any reasonable person (let alone a sceptical scientist) would be satisfied that C&W’s post-1993 data fails to represent a continuation of the 1888-1893 tide gauge series.
What is the point of splicing two distinct measures, unless to “hide the decline” of correlation between the two?
Well stated Barry,
I worked for many years in industry with various types of data series, and when we graphed them we never hid their character as individual sets: they were always distinguished by using different symbols, different colors, etc. Merging them together is, like you say, hiding information. I’ve never spliced two data sets in my life. I think it is scientifically incorrect procedure. Two data sets, whether collected by different methods, or even collected by the same method but just with a gap in time, are not the same thing and cannot be correctly treated as if they are.
Barry — The problem is that sea level can be influenced by things like river flows, sea temperatures, and prevailing winds that can vary on decadal scales. Tide gauges — especially those with long records — are found only along coast lines (duh) and are heavily concentrated in the Northern temperate zone. Not the sampling one would like to see.
Satellite measurements OTOH, cover the world’s ice-free oceans pretty much evenly.
No one expected the two to yield exactly the same result for sea level rise. But the discrepancy between the two data sets is much larger than anyone expected or can easily explain.
I can explain it: There are so-called scientists with an agenda who have no problem fudging data and making stuff up.
Over in West Australia the land has been sinking, which has not made life any easier for the boffins.
https://www.theguardian.com/environment/2015/oct/22/perths-double-whammy-as-sea-levels-rise-the-city-itself-is-sinking
In passing let me point out that the Jason/TOPEX satellites are orbiting at an altitude of 1,336 km. That is 1,336,000,000 millimeters, over a billion.
That means that to measure the sea level to an accuracy of ± 1 mm, you need to have an accuracy of greater than one part per billion.
Now, making a length measurement to an accuracy of one part per billion is not easy even in the lab.
But in this case, your measuring device is whirling around the planet, subject to varying gravity fields, moving at 26,000 kilometers/hour (16,000 mph), and measuring a surface that is never still, but instead has waves up to 18 m (60 ft) tall …
Now, to me it is an engineering and mathematical marvel that they can do it at all … but we know they can, because it images Rossby waves and eddies on the ocean surface.
However, the unanswered question for me is not track-after-track repeatability that allows them to image eddies. It is long-term drift, either in the instruments themselves or in the orbit … and if that is only a couple of mm per year it could easily explain the difference between the tide gauge records and the satellite records.
Regards to all,
w.
Hey, your not supposed to go into any details: stuff from NASA/ ESA is blindly 200% reliable Science. Leave it to the High Priests.
How do the proponents of sea level measurement by satellite keep a straight face? Surely they must know the technique is nonsense?
Can we be sure they are not sniggering up a laugh riot as they construct their narratives and spin their data?
There have been moments I have felt rather certain that we are being laughed at and played for fools.
Willis
That means that to measure the sea level to an accuracy of ± 1 mm, you need to have an accuracy of greater than one part per billion.
It turns out that they are measuring time between a radio pulse and the mid point of the rise of the reflected pulse. Time is one thing we can measure with extreme accuracy. So much so that it probably doesn’t make much difference whether they are observing from 1300km, 130km, or 1300m. There are a lot of issues with things like uncertainties in satellite position (a couple of cm), sea surface wave shape, etc, etc, etc, so they really need to average a LOT of measurements. Which they do. It’s easy to identify problems with the measurement, but it’s not easy to explain why the problems don’t average out, or alias into seasonal affects or otherwise behave tractably.
Incidentally. It’s a fine article. Congratulations.
Ahhh . . . but the satellite altimetry data is not just as simple and measuring time. The speed of the satellite’s radio pulse is not the speed of light in vacuum . . . electromagnetic energy traveling through a medium (e.g., the Earth’s atmosphere) has a velocity of propagation that is lower than the speed of light in vacuum. To find the speed of EM waves through any other medium, its speed of light in vacuum has to be divided by refractive index of the medium. For “air” a typical refractive index is given as 1.0003, so this represents a 300 ppm reduction in EM propagation speed versus vacuum for that portion of the radio pulse propagation back and forth through the atmosphere.
However, the effective refractive index taken over the vertical column of Earth’s atmosphere at any given lat/longitude will vary with such things as total column mass (barometric surface pressure), average column temperature, and average column absolute humidity.
I don’t know the extent to which these variations are accounted for in deriving satellite altitude based on EM pulse timing, but I can easily believe that due to the highly variable nature of Earth’s atmosphere they can easily account for tens to hundreds of ppb errors that are not corrected.
Gordon Dressler,
The increase of the optical depth due to the atmosphere is 0.0003 * 7.7 km= 2.3 m (0.0003 is the refractive index of air minus 1, the 7.7km is the thickness of the atmosphere for 1 bar).
Airpressure can vary by 10 %, so optical depth by .23 m.
A larger effect is that a 10 % higher airpressure lowers the sea surface by 1 m, this adds up to 1.23 m increase in optical depth for 10 % increase in barometric pressure.
Ionospheric Delay is indeed an issue. For Jason, they estimate it using a dual frequency technique. As with most everything in the world of satellite Sea Level Rise, there is probably some error in their estimate of delay, but its hard to see why any errors don’t ether cancel or resolve over a very large number of measurements to a constant bias in their estimate of sea level — which shouldn’t affect the estimate of Sea Level Rise. (.. unless ionospheric delay itself is decreasing or increasing over time — which it probably isn’t … much? Hmmm … What’s the affect of the solar sunspot cycle on ionospheric delay?)
Keep in mind that the satellites are making more than 1000 measurements every second and are moving their “target point” about 8km (I think) laterally every second. A lot of stuff really will average out over time.
“Jason-2 flies in a low-Earth orbit at an altitude of 1336 km. With global coverage between 66°N and 66°S latitude and a 10-day repeat of the ground track, Jason maps 95% of the world’s ice-free oceans every ten days. Sea surface height accuracy is currently 3.4 centimetres, with 2.5 expected in the future.” — source: https://www.eumetsat.int/jason/print.htm#page_1.3.0
So we are faced with the C&W data giving a slope of 2.1 +/- 0.5 mm per year for the last 20 years using a large amount of data from one or more spacecraft instruments (presumably the Poseidon-3 dual frequency altimeter that is on Jason-2 or something with similar accuracy), having at best a 25 mm accuracy.
Go figure.
I think the accuracy has more to do with time accuracy than distance. I think you can get atomic clock accuracy on satellite emphermeris which should make such accuracy possible.
Tom
The problem is, if the measured time decreases, how do you tell if it is the result of an increasing sea level or a decaying orbit?
how do you tell if it is the result of an increasing sea level or a decaying orbit?
Orbit decay at 1300km should be pretty minimal and in any case, the satellite is tracked and any changes in its orbital velocity should be known quite well and reflected in the data processing.
Of course, corrections for that and a hundred other things will make the processing algorithm inordinately complex and opaque.
Maybe it has to do with what is actually meant by the term sea level, and how the level of the sea responds to the variations in the gravity field of the Earth by as much as a hundred meters in the open ocean.
All this is what I was getting at with the minute physics video.
the satellite measurements, it seems to me, have to be oriented with respect to what the ocean shape of the sea surface (IOW…what is “sea level”) is.
And the model made by geodesists is not accurate enough, and the gravimetric field is constantly varying for Lord only knows how many reasons and by how much.
I read the Jason 2 spec manual in its entirety for essay PsuedoPrecision in ebook Blowing Smoke. Is (was?) available on line. Relevant portion is §2.3.1. The average repeatable track accuracy spec (one sigma) is RMS 3.4 cm (NOT mm) with instrument drift<= 1mm/year. I dunno how they can possibly convert that reality to the much tighter precision claimed.
There are three main uncertained that have to be accounted for in sea level satellite altimetry. 1. Signal delay caused by varying atmospheric humidity, albeit lowest over the oceans but varying for example T altitude with diurnal thunderstorm washout in the tropics.
2. Wave height, as signal from trough is bigly different than from crest. The processing ‘assumes’ average 2 meter wave height.
3. Orbital decay, as these satellites do expeience slight atmospheric drag.
Bad sciencetist but good ‘climate’ sciencetist in the sense their work offers scary headlines and is the type to get into ‘reports’ and that rather than validity is what matters.
Let me close by saying that I think that it is very bad scientific practice to splice together a terrestrial and a satellite record unless they agree well during the period of overlap …”.
===================================
Prof Humlum at his excellent climate4you website:
” Data from tide-gauges suggest an average global sea-level rise of 1-1.5 mm/yr, while the satellite-derived record suggest a rise of more than 3 mm/yr. The rather marked difference between the two data sets has still no broadly accepted explanation, but some of the difference is likely due to administrative changes introduced into the raw data obtained by satellites …”.
Also the data sets are measuring different things:
“… Another factor that may explain some of the difference between tide-gauge and satellite data is probably that while any temperature-driven volume expansion is recorded by the satellites, this change is not affecting tide-gauges at coastal locations, as the water depth here decreases towards zero …”.
Wait a second, on that last point: If the volume of the oceans is increasing due to thermal expansion, it should not matter what the depth is where it is measured, should it?
This would be like if I had a container that was flared out at the top, and heated it up so the water in it expanded.
It would not matter what the shape of the container is…the whole surface would rise by the same amount. That it is shallow at the edge would not mean it rose less at the edge than over the middle f the container.
Would it?
I must be missing something here.
Wonder what the guy who knows that the 50km3 goes in the numerator thinks?
Sorry: “…would not matter what the shape of the container is…”
Fixed.
w.
I think the answer is that the edge or “coastal locations” move out, or move inland.
The problem as the tide gauges show is that the Sea surges depending on the wind and to a smaller extent the Currents.
It has been shown that the sea sloshes not only due to spin, Moon but also wind, as they change so can the tide height.
As well as that the expansion is not equal between north, tropic and south so expansion can’t be equal due to temperature increases in the short term.
Does Prof Humlum apply this same caveat to satellite TLT data?
A non sequitur. I don’t think the people who measure satellite TLT data mix their data with land-based thermometer measurements.
But they do calibrate using, IIRC, balloon measurements of the troposphere.
They certainly make administrative changes to the way they calibrate the raw data though, as evidenced by the fairly recent substantial, and mutually contradictory, changes to both UAH and RSS TLT.
Thanks for taking the trouble to download and post the tide gauge data in a single file Willis. Much appreciated.
Two quick questions:
First, was the spatial distribution of your subsection taken into account? For instance, do you know whether your surviving sets (258 from 1,512) are evenly distributed globally rather than concentrated in regions where sea level rise may be slower than the global mean? My understanding is the SLR is not evenly distributed.
Two, 21 years from start 2003 (start of satellite MSLR data) brings us to end 2013. Nerem and Fasullo appear to use tide gauge data up to end 2015 and satellite data up to end 2017. Might this also affect the difference between the trends they found and yours?
Thanks.
Let me close by saying that I think that it is very bad scientific practice to splice together a terrestrial and a satellite record
Even if they agree reasonably well. The practice of data splicing should be banned
Also of note with this splicing is the terrestrial and a satellite records of data have radically different sampling rates. Can it ever be honest science to splice together such data?
Can not trust anyone any more-not even Church 🙂
Well done Willis E
There is long records of sea level change treated to show changes during time.
SF-CA shown here: https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?plot=50yr&id=9414290
NASA had the same trix when they changed from gauges to satellites and stated the acceleration. I hope it was uneducated but fear something else.
Good work Willis!
I would add and want to point out, the empirical oddness of the global sea level metric itself.
I stood at a particular beach at one spot on the earth and even when accounting for isostasy the data showed a rising sea level trend, and yet on that day, that month and that year, all the tide marks were equal to the those of the earliest data recorded.
This is the oddness of the metric, that it is not like filling up a bathtub that politics would have us assume. The trend is probably true but it is divorced from reality in a peculiar way because the trend could change and would then have even less meaning! The fluctuations – the ups and downs – in the signal may be larger than the total trend of course and I imagine there are good statistical explanation for this situation.
As a laymen this real world experience tends to fill one with doubt about the fears of global sea level rise!
Jevrejeva et al, 2014, Global Mean Sea Level Reconstruction, from PSMSL data, with GIA…
If there’s an anomaly, it’s from 1951-1992…
And, no matter how you slice it, the anomaly is insignificant…
Some investigators have taken averages of tidal data, corrected for vertical land movement, and analyzed these in short time segments. They conclude that on decal time scales, sea rise varies over rates of almost zero to over 3 mm/yr. It is combinations of these varying global sea rise rates that give the overall trend over the past century plus.
And then they exaggerate the trend, assume acceleration will occur at rates not seen since meltwater pulse 1A, and project that trend to the year 2100 and claim this is what will happen and it is a function of, and only of, CO2 concentration.
California is at the point of considering condemning sea side property based on this garbage “science”. Which is really nothing more than hyped speculation and WAGuessing.
Interestingly in Figure 5 they used three dutch cities. Vlissingen, Hoek van Holland and Den Helder. I suspect that the readings there have nothing to do with sea level rise and everything with the sinking of the land. The soil in the Netherlands is made of peat. Because we pump out the water the soil inclines, which causes the land to drop. This is on top of the natural decline that is caused by the disappearance of the land ice on the Eifel and Vogezen that was present during the last glaciation.
I wonder if they included these considerations in their analysis.
Koen,
The tectonic subsidence along the Dutch coast is ~0.5 mm/year.
The Dutch tide gauge stations measure ~1.5 mm/year sea level rise, which result in a net rise of ~1 mm/year.
For more information see:
https://klimaatgek.nl/wordpress/2016/07/22/nederland-en-de-zeespiegel/
It is in Dutch, but there is a translate button.
I assume that during the Weichsel glaciation there was no ice sheet in the Eifel and Vosges.
Meticulous and technically outstanding work.
Robust conclusion.
Devastating implications.
Well done and thanks, Willis.
If the trendlines diverge where the data overlaps, then the data can’t be spliced. It’s really that simple.
But if others plan to reduce CO2 emissions by building windmills and solar panels, then I’d like to fight global sea rise by piling ice at the center of Antarctica. To study the feasibility I’ll need a large grant.
OK. I did not see any mention of Earth Tides in this whole thread. The planet is not a solid, it’s a viscous blob of stuff that is affected by the gravitational fields of the moon and sun that changes its shape diurnally. The water in the oceans is a whole lot less viscus than the earth under it so it’ll “seek its level” in response to the changes in the shape of the earth. The magnitude of the Earth Tide is on the order of a foot, that a whole lot more than the claimed sea level rise.
From the Encyclopedia Britannica:
Earth tides are similar to ocean tides. The Earth deforms because it has a certain degree of elasticity; were it perfectly rigid, there would be no Earth tides. Several tidal components mathematically can be shown to exist, but only four are large enough to be generally measurable; these are the lunar diurnal, the lunar semidiurnal, the solar diurnal, and the solar semidiurnal tides. Diurnal tides have a period of approximately 24 hours (1 day), and semidiurnal tides have a period of approximately 12 hours (1/2 day). The actual amplitudes of these tides in terms of vertical movement of the surface of the solid Earth are about one foot or less.
This was unfamiliar to me as an area of study. Here is a link to the Wiki page with general discussion, and links to the sources. Of particular interest to me were the implications for GPS and CERN.
https://en.wikipedia.org/wiki/Earth_tide
The sea level is affected far more than any of these outside influences, by the gravimetric field of the Earth itself.
The area of the Indian Ocean South of India, for example, has a negative anomaly that makes sea level there 100 meters of so lower than the average height, and not too far away from there, East and Southeast of Australia, a positive anomaly piles water up 80 meters higher than the average height of sea level with respect to the center of the Earth.
These gravimetric anomalies have been carefully mapped, but how often are the measurements redone to assess the rate of change?
The overall takeaway is that an enormous numbers of factors influence the height of the sea at any given place and time, and many of these are poorly studied.
But the warmistas are running the show, and as with temperature effects, very little is taken into account and all increases are assumed to be due to global warming caused by CO2 concentration increases in the atmosphere. The satellite data for sea surface is corrected, very questionably, by the assumption that the ocean bottom is sinking and a further .3 mm per year is tacked on for good measure.
Blame it on your SUV and deniers, give dispensation for anyone who toes the warmista party line… lather, rinse, repeat…ad nauseum.
I find it an amazing co-incidence that sea level rate of rise instantly doubled in 1993, the very year satellite data started. Yet not one surface station shows the doubling.
How can we possibly think that satellites and tide gauges are measuring the exact same thing?
The distance from a fixed point in earth orbit to the center of Earth is a different benchmark (than tide-gauge benchmarks) against which to make sea-level measurements, isn’t it ?
To mix the two measures seems pretty obviously wrong to me.
Or am I seeing it wrong?
It’s basic science to never mix data from two completely different sources with different measuring mechanisms to get a trend. The best one can do is to compare the two sets. This comparison will show very different results. To me the mixing of the two is evidence of deliberate science fraud to give a result they wanted.
Another manifestation of the incredible power of Catastrophic Anthropogenic Global Warming.
The whole meme is reminiscent of Kwai Chang Caine.
We know it is real, because they tell us so, and yet…looked for, it cannot be seen, listened for, it cannot be heard, felt for, it cannot be touched.
The Earth and the creatures on it are fragile…fragile as the wings of a butterfly, and the terrible heat of CO2 sticks to and destroys everything…clinging, like the cocoon of a silkworm.
To defeat it then, we must be able to walk upon the earth and leave all as it was before we arrived, as a Shaolin priest walks the rice paper and leave no trace, and we must run an industrial society and feed the hungry billions, powered by only the sun and the wind and a few unicorn farts (if we are fortunate enough to find any), as a Shaolin priest can walk through walls.
When we can snatch the pebble from the warmista hand, we will have learned.
Interesting that Willis posted his article during the same period that I have been obsessing on the sea-level-acceleration claim. So, I guess these papers, which I have been reading (attempting to ingest) are vindicated:
Curtis E. Larsen and Inga Clark (2006) A Search for Scale in Sea-Level Studies. Journal of Coastal Research: Volume 22, Issue 4: pp. 788 – 800.
http://www.jcronline.org/page/doi/full/10.2112/03-0123.1
Kolker, A.S. and Hameed, S. (2007). Meteorologically driven trends in sea level rise
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2007GL031814
Houston, J.R. and Dean, R.G., (2011). Sea-level acceleration based on U.S. tide gauges and extensions of previous global-gauge analyses. Journal of Coastal Research
http://www.geo.hunter.cuny.edu/~fbuon/PGEOG_334/BnC/Lecture_pdfs/jcr_dean_gauge.pdf
Scafetta, N., (2013), Multi-scale dynamical analysis (MSDA) of sea level records versus PDO, AMO, and NAO indexes, Climate Dynamics
https://www.researchgate.net/publication/236263813_Multi-scale_dynamical_analysis_MSDA_of_sea_level_records_versus_PDO_AMO_and_NAO_indexes
Kench et al., (2015), Coral islands defy sea-level rise over the past century
http://www.geo.hunter.cuny.edu/~fbuon/PGEOG_334/BnC/Lecture_pdfs/jcr_dean_gauge.pdf
For millions of years there are billions of km³ of fresh water (from rains, rivers & rivers) that have poured into the seas & oceans … WITHOUT WHERE THEY DO NOT UP !! ! That’s it! Quite simply because water continuously seeps into the ocean and sea floors to the magma where this poisonous soup (the fish shit in the sea!) Is heated / boiled and goes up (as in a coffee maker) to the sources (hot or cold depending on the altitude) and towards the water tables it fills.
Outstanding job, Willis. There is another way to show that the post 1993 trend of ~3.6mm/yr must be spurious. Wrote about it in my guest post here on sea level rise a while ago (couple of years?). It doesn’t close. To a first order approximation SLR should equal thermosteric rise plus ice sheet mass loss. Thermosteric rise can be estimated from ARGO since about 2005. Ice sheet mass loss can be estimated from GRACE with appropriate regional GIA asjustments (Antarctica modeled GIA was wrong by a factor of four until diff GPS estimates became available in 2013–Steve McIntrye had a long technical post on that), or by IceSAT (Zwally 2015). Closure is about 2.2-2.3mm/year NOT 3.6.
The closure range corresponds very nicely with the 60-70 diff GPS vertical land motion corrected long record tide gauges. Moerner says you need at least 60 years to account for the lunar nodal effect. IMO it is 75 years. So depending on the record length sample criteria, you get between about 60 and 70 stations and 2.2-2.3mm/yr. Possible issue: The resulting sample is Northern hemisphere and Atlantic ocean scewed. I didn’t bother to create a smaller unscewed sample to check, because was focused mainly on closure.
Willis,
Most tidal gauge sea rise data are affected by vertical land movement. Several investigators, not just Church & White, use GPS satellite data to correct for that. Then, many such tidal data are averaged to obtain a global data set. Doing this indicates an increased in sea rise beginning about the time satellite altimetry data on sea level first became available. Data on ocean heat indicate increases in the 1980s, and thermal expansion comprises about 40% of overall sea rise (ice melting most of the rest). If one argues that altimetry data are wrong, then the GPS data used to correct tidal data fro vertical land motion also must be wrong. These are the same GPS data used from many other positioning determinations.
Individual tidal data may differ considerably from the global data, both because of land movement and because sea level at sea shores depends on several other characteristics, e.g. tides, winds, temperature, profiles, gravity anomalies, etc. For those living at a particular seashore, it is local se level that counts, not global sea level.
GPS resolution is suspect as well. ‘Commercial’ horizontal resolution is claimed at 4m, with vertical ‘worse’. Anyone have insight into what the govt (i.e., military) resolution is?
The GRACE-ARGO sea level data (since about 2001) agree with the radar altimetry data. Both these and the GPS-corrected tidal data use satellite data mutually corrected for the Earth’s geode (non-spherical corrections). This may be the only commonality among the three sea level data sets.
I do think that GPS data for individual stations should be shown separately. That’s just a personal prejudice – but having been to an assortment of monumented survey locations over the years that had moved over a metre horizontally between GPS surveys I feel it’s always good to see how mobile your benchmark is.
I am not a statistician, just a computer nerd. But if the Confidence Interval of the study doesnt even touch the confidence interval of the tidal gauges, doesnt that imply that the calculation of the confidence interval for the study is incorrect?
For anything scientific or fact-based…yes.
But for religious affairs such as “climate change” and related matters…oh, heck no!
I fear that the concept of “global sea level” suffers the same shortcomings as the concept of “global temperature”.
There is no such thing as a “global sea”, whose level we can measure as such. It’s a regional concept, and, unless all regions of the world are undergoing monumental inundation by the sea simultaneously, and each region reports this, I cannot see how we ascertain any threat that the water of Earth is threatening the land of Earth any more than it always has.
I think that the ancient Greeks had a conception about a global ocean, and they named a god, Oceanus, who was the main overseer of it. Poseidon, was the Mediterranean sea God, if I understand correctly, but, as Willis would say, “I digress”.
Now for some shameless self promotion along these lines:
https://fineartamerica.com/featured/oceanus-greek-god-robert-g-kernodle.html
Here is a link to a video from Tony Heller from last year.
In it, he details just a few of the more obvious instances of tampering with data, and among them are the data related to sea level rise.
He has a few very interesting graphs in this video, and among those is one from NASA from 1982, showing that there were, as of the 1982 appraisals of total global sea level changes, two distinct multi decade periods in the 20th century in which sea level was mostly static to declining from earlier peaks, before rising slightly again in subsequent years.
This graph can be seen at 3:44 in the video. The y-axis of the graph is labelled “sea level change (mm)”, which might suggest that it is a graph of changes in the rate of sea level rise, but a more careful look shows that the lines of the graph show observed sea level, not rates of change.
Superimposed on this graph are the huge alterations that have been done to the more recent versions of this graph.
Also, consider this in conjunction to what NOAA says about the individual tide gage charts and how the values for the individual months are arrived at. It is not raw data in any way, shape or form. In fact, it may be adjusted per revisions to what is now being reported as global rates of sea level rise…hard to say without more info on exactly what this sentence means:
“The plotted values are relative to the most recent Mean Sea Level datum established by CO-OPS.”
That is part of the this description of what the tide graphs are representing:
” The plot shows the monthly mean sea level without the regular seasonal fluctuations due to coastal ocean temperatures, salinities, winds, atmospheric pressures, and ocean currents. The long-term linear trend is also shown, including its 95% confidence interval. The plotted values are relative to the most recent Mean Sea Level datum established by CO-OPS. The calculated trends for all stations are available as a table in millimeters/year and in feet/century (0.3 meters = 1 foot). If present, solid vertical lines indicate times of any major earthquakes in the vicinity of the station and dashed vertical lines bracket any periods of questionable data or datum shift. ”
As with anything related to climate change and climate science, it may well be that what they say is not what is true…or at least not what they were saying about the same information before they decided to revise it to avoid any contradictions to the prevailing narrative.
At 7:17 in the video is another fascinating graph, which is a bar chart of the rates of rise for 233 tide gage stations. It clearly shows that the value of over 3.9 mm per year of sea level rise is actually only visible on about 10% of tide gage charts. Have a look at it…I would like to know what other people have to say about it.
In fact the whole video is a snapshot look at how various agencies have altered data left and right to agree with what they “expect” should be happening, given that CO2 is increasing and thus the world is warming steadily and we are now hotter than any other time in history, ice is melting at both poles and the Arctic will soon be ice free for the first time since the Earth cooled 4.3 bajillion(or is it gazillion?) years ago, and of course sea level is therefore rising at an ever increasing rate and thank the Almighty we have satellites that caught it (after they adjusted the satellite readings to correct “faulty sensors”)…
Someone up top asked for an unpacking of something that someone else said, and the question is aptly phrased for what needs to be done to even begin to unravel what the real story is with any of these measurements.
The records are recorded and kept by people who have an agenda, and telling the exact truth and detailing objective reality is not any part of that agenda…that is about the only thing that seems for certain.
https://youtu.be/NJtpdTbHY30
Academic trick No.523.
When you want to get an increasing trend when there isn’t one: splice different datasets and select which parts of one to mix with the other. Wella!
Someone should write a book on the other 522.
This single thread alone demonstrates why WUWT and its commenters are such a treasure. Thanks, Willis. Thanks, Menicholas. And the rest of you. What a treat to be able to share such a calm, reasoned, rigorous, interesting discusson.
And thanks to Anthony for making it all happen.
Willis and his love of data and checking things out when they don’t feel right shows what is wrong in the climate industry.
What Willis has done should have been done hundreds times around the world by undergraduate students, as a repition experiment. Usually, most undergraduates confirm the original findings within experimental error. Very occasionally they spot an error.
The real question here is why are datatasets, papers, theories etc not being tested all the time as part of routine education?
Two possible answers- students not allowed to by their profs, or errors are not allowed to be published.
Have the original authors been approached for a comment?