Sea Level Rise Accelerating? Not.

Guest Post by Willis Eschenbach (NOTE UPDATE AT END)

There’s a recent and good post here at WUWT by Larry Kummer about sea level rise. However, I disagree with a couple of his comments, viz:

(b) There are some tentative signs that the rate of increase is already accelerating, rather than just fluctuating. But the data is noisy (lots of natural variation) and the (tentative) acceleration is small — near the resolving power of these systems (hence the significance of the frequent revisions).

(c) Graph E in paper (5) is the key. As the world continues to warm, the rate of sea level rise will accelerate (probably slowly). 

This question all revolves around whether the rate of sea level rise is relatively steady, or whether it is accelerating … so how do we tell the difference?

Well, how I do it is to fit two models to the data and see which one works better. The first is a straight-line model (a linear fit), and the other is an accelerating model (a “quadratic” fit). Figure 1 shows an example of some pseudo-tidal data which in fact has an accelerating rate of sea level rise. I’ve created it by simply adding an accelerating trend to an actual tidal record.

tide pseudodata accelerating

Figure 1. Artificial pseudodata of a tidal gauge recording an accelerating rate of sea level rise.

As you can see, the blue line showing an accelerating (quadratic) fit matches the data much better than the linear fit (red). How much better? Well, that’s measured by something called “R-squared” (R^2). This is a value between zero and one which measures how well the given line explains the dataset.

The R^2 for the blue line (0.88 ± 0.02) is much larger than the R^2 for the red line (0.77 ± 0.02). And since the difference between the two values is greater than the sum of the standard errors of the two values, we can say that the difference between them is statistically significant. In other words, in the Figure 1 case, we can say that there is a statistically significant acceleration in the dataset.

So that is what I planned to look at—whether the difference between the R^2 for the linear and the quadratic fits is greater than the sum of their standard errors.

With that as prologue, let me discuss my methods. I took the full tidal dataset from the Permanent Service for Mean Sea Level. It has 1,505 tide station records in it. However, as with most historical datasets, there are lots of gaps and stations with short or spotty records.

So I had to use a subset of the data. Because the long lunar tidal cycle is just over fifty years, you need at least that much data to get a serious estimate of the rate of sea level rise. And we are interested in any recent acceleration. So I limited my analysis to tidal stations with data starting before 1950 and ending after 2015. This cuts the list down to 171 stations which cover the period of interest.

However, some of these are missing a lot of data, some with over half of the data gone. I wanted enough data to have faith in the analysis, so I further limited the dataset to those stations having 95% or more of the data during 1950-2015. This further reduced the number of tidal stations to 63. Figure 2 shows a sample of 10 of these.

typical tide gauge records

Figure 2. Typical records which fit the criteria of the ex-ante data selection process (95% data coverage from 1950-2017)

Now, my Mark 1 Eyeball says that if there is acceleration there, it is minor … but let’s look at the numbers. Here is a scatterplot of the R^2 values of the linear fit versus the R^2 values of the quadratic fit:

comparison fits linear quadratic

Figure 3. Scatterplot, R^2 of the linear fit vs. the R^2 of the accelerating (quadratic) fit. Dots above the diagonal line are stations where the R^2 of the accelerating (quadratic) fit is larger than the R^2 of the linear fit.

As you can see, in almost all cases the gain in the goodness of fit when we go from linear to quadratic fits is trivially small, invisible at this scale. And when I examined the gain in R^2 versus the standard errors for each of the 63 stations, in every single case the accelerating fit was NOT statistically better than the linear fit.

In other words, not one of these datasets shows statistically significant acceleration.

And that is why at the top I said that I disagree with the following statement from the other post, viz:

There are some tentative signs that the rate of increase is already accelerating …

Simply not true. Figure 3 shows clearly that the tidal gauges contain no such “tentative signs”. NOT ONE of these 63 full tidal datasets shows statistically significant acceleration, and more to the point, most of them show only a trivially small difference between acceleration and a simple linear fit.

The other statement I disagreed with was:

As the world continues to warm, the rate of sea level rise will accelerate (probably slowly) …

Look, this is just the same nonsense that the alarmists have been peddling for the last thirty years, that in the future the sea level rise will accelerate, that New York will be underwater, and the like … but it has been thirty years since the first bogus prognostication was made, and there is still no evidence that the sea level rise is accelerating.

Look, I’m all in favor of taking care about the future … however, call me crazy but I need EVIDENCE before I start hyperventilating about Miami sinking into the ocean.


5 PM, the dreaded global warming has cooled down now. Me, I’m going to post this and then go outside to lay some pavers in the new level space I just made with my own sweat. Plus a rented backhoe. I could have hired someone, but why should illegal immigrants have all the fun? I like living in the hills … but this is the first and only flat spot on my land, so I’m making it nice.

the patio

What a universe!

Best to everyone,

w.

PS—The Usual: When you comment, please QUOTE THE EXACT WORDS YOU ARE DISCUSSING, so that we can all be clear about your precise subject.

DATA—I’ve put the 63-station data here, as a CSV file so that anyone can use it in Excel or any other program.

[UPDATE] Over at Tamino’s website, where since about 2009 I’m barred from commenting because I was asking inconvenient questions, he points out that there is a simpler and more accurate method for finding out if a dataset contains acceleration. This is to see if the squared term in the quadratic equation is statistically significant after correction for autocorrelation, duh … he is correct.

My thanks to him for pointing this out, although I do have to deduct points for his repeated ad hominem attacks on me in his post … haters gonna hate, I guess.

Using his method I identified seven of the sixty-three stations as having statistically significant acceleration and three stations with statistically significant deceleration. However, the average value of their acceleration is 0.015 ± 0.012 mm/yr2 … which is not statistically different from zero. Here are the stations and their accelerations:

       VLISSINGEN         BALTIMORE            SMOGEN          KEY WEST         KETCHIKAN

           0.0605            0.0542            0.0676            0.0477           -0.0543

WEST-TERSCHELLING        SANDY HOOK            JUNEAU             SITKA         KWAJALEIN

           0.0979            0.0510           -0.1052           -0.0573            0.1258

I note that one station he says has significant acceleration doesn’t appear in this list (Boston). I find that the p-value of the acceleration term for Boston is 0.08, not significant. I suspect the difference is in how we account for autocorrelation. I use the method of Koutsoyiannis, detailed here. I don’t know how Tamino does it.

I would also note that the average acceleration of the entire 63-station dataset is 0.014 ± 0.008, still not statistically significant. And if this turns out to be the long-term acceleration, currently the rate of rise is on the order of a couple of mm/yr, or 166 mm (about 7 inches) by the year 2100. IF this increases at 0.014 mm/yr2, this will make a difference of 48 mm (under two inches) this century.

Curiously, in the previous fifty-year period 1900-1950 there are only three sites with significant acceleration out of 38 datasets covering the period, and none are in the first list:

NEW YORK (THE BATTERY)              HARLINGEN                SEATTLE

                0.0976                -0.1182                 0.0959

Whatever any future sea level acceleration turns out to be, it is very unlikely to put the Statue of Liberty underwater anytime soon …

Man, I love writing for the web. All my errors get exposed in the burning glare of the public marketplace of ideas, I get to learn new things, what’s not to like?

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July 21, 2017 1:18 pm

Willis, thank you for your essay.

RAH
July 21, 2017 1:38 pm

Ok. Though this is a statistical methods argument this truck driver has a more direct question.
Where the hell is the water coming from? Most of the Antarctic is gaining SMB. Though Greenland ice sheet SMB was decreasing a little it is now gaining. Neither can account for the amount of SLR it seems to me.
Thermal expansion and ground water are accounting for the bulk of the rise?

Reply to  RAH
July 21, 2017 2:24 pm

Thermal expansion and creative accounting are apparently the two main drivers of SLR… 😉

afonzarelli
Reply to  RAH
July 21, 2017 3:56 pm

comment image

stevefitzpatrick
Reply to  RAH
July 21, 2017 4:44 pm

Thermal expansion, ground water pumping, and melting of high altitude glaciers are all contributors. There probably is some net accumulation of ice in the Antartic, but I think Grace data continues to indicate net loss in Greenland. That said, claims of more than a meter sea level rise before 2100 are utterly bonkers…. more likely is somewhere under 50 cm by 2100. The Statue of Liberty is safe…. though the liberty the Statue celebrates is truly threatened by those who insist people must “fundamentally change” how they live their lives to ‘avoid catastrophe’. It’s just science being subverted and corrupted to advance green/left policies..

RAH
Reply to  stevefitzpatrick
July 22, 2017 4:05 am

Thank you to those that responded.
GRACE data on ice masses overlaying areas like some in Greenland which have ongoing active geological/ Geothermal processes seems to have been less than optimal.
Afonzarelli.
Your chart runs to 2014 but there has been more than one paper published since then which has indicated the SMB of Antarctica is actually growing slightly. That would indicate that the contribution from Antarctica would be negative.
As for the Steric contribution that would correlate with the higher SSTS.
I guess over all one should expect that if that chart ran to the present the total would be somewhat less?

Brian
July 21, 2017 1:52 pm

Forrest,
It’s not clear that you understand what Willis is doing. You are correct that a linear model might not be the best model for sea-level rise, but Willis isn’t trying to model sea-level rise. He is looking for evidence of acceleration.
As you may or may not know, any finite and continuous function can be represented by a power series. So whatever the correct model for sea level is, it can be represented by the series d(t) = a0 + a1*t + a2*t^2 + …. a0 would be a constant sea level, a1 is a constant change in level, a2 is a constant acceleration, etc. If there is any acceleration in the data, it will show up as a nonzero a2, no matter what the correct model is. That’s why the linear vs. quadratic fit is the right test to do.
It’s true that such a fit would not work prior to 1950, but it does allow Willis to conclude–correctly–that there is no evidence of acceleration between 1950 and 2015. That’s all his post is about and he did the test the way it should be done.

Brian
Reply to  Brian
July 22, 2017 10:10 am

Forrest,
I can see that you don’t understand what I’m talking about. I am not presenting some “ideas.” I am stating basic mathematical facts, known to anyone with a decent knowledge of calculus.
If sea level can be calculated at all (which you are assuming when you speak of a model), it is certainly a continuous and finite function of time. If sea level is definable at all (such as the average of sea-level gauges around the world), it is calculable for every moment in time. Since it is nonphysical for the sea to suddenly be, say, three inches higher without going through intermediate heights (such as 1 inch, 2 inches, etc.), it is certainly continuous. And since it is also nonphysical for the sea level to be infinitely high, it is also finite. Any accurate model of sea level, then, would also be continuous and finite. Again, these are not ideas, just simple facts based on common sense and basic calculus.
So why is Willis justified in stopping at the quadratic term? Because he’s only looking for evidence of acceleration. Suppose the actual model is more than quadratic. The we could rewrite the series as
d(t) = a0 + a1*t + (a2 + a3*t + a4*t^2+..)*t^2.
The third “constant” (the part in parentheses), which now depends on time, is the true acceleration. For Willis’s best fit, it will be calculated as a single number, basically the average acceleration over the chosen time interval. But it will be nonzero if there is any acceleration at all. If it is zero, then all true constant terms (a2, a3, a4, …) must be zero also.
Take a look at Willis’s update based on Tamino’s criticism. The direct approach is to see if the term in parentheses is actually zero. It is. But what Willis did originally is still correct, if less direct.

seaice1
July 21, 2017 4:17 pm

Your analysis seems to show that an accelerating fit is perhaps marginaly better than a linear fit (a few more points above the line than below it), but essentially both are just as good. It seems that this simplistic analysis is unable to differentiate between linear and rising, and it is not possible to distinguish between them using this method.
Thus an accereraing sea level is just as likely as a linear one, from this analysis.
This seems to show that this is not a good way to distinguish between linear and rising rates.

1sky1
July 21, 2017 4:48 pm

Those interested in a professional view of what Walter Munk calls the “enigma’ of sea level should read: http://www.pnas.org/content/99/10/6550.full
Those seriously interested in the question of accelerating SLR on a global scale will recognize that a sparse sampling of tide gauge records examined only via regressional methods applied on a time-scale dictated solely by data availability doesn’t provide a scientifically satisfactory answer.
On a Friday afternoon, I can’t take the time to replicate a longer comment explicating these two issues, which totally disappeared, because WUWT was “not responding” to my submission.

afonzarelli
Reply to  1sky1
July 21, 2017 5:08 pm

1sky1, they’ll eventually show up… (it’s been happening to everybody of late)

1sky1
Reply to  afonzarelli
July 22, 2017 4:20 pm

I’ll believe it when I see it. Another comment disappeared on this thread early this afternoon.

July 21, 2017 7:05 pm

Willis is an a-hole.

There is no such thing as a” lunar tidal cycle is just over fifty years”

No wonder he can’t get anything published. he’s an idiot.

Reply to  Steve Heins
July 21, 2017 7:10 pm

The Metonic cycle is 19 years.

afonzarelli
Reply to  Steve Heins
July 21, 2017 10:43 pm

Willis may be a lot of things, but one thing he ain’t is an idiot. (watch your manners steve)…

Reply to  Willis Eschenbach
July 22, 2017 1:00 pm

The “here” link does not seem to work.

Rob Bradley
Reply to  Willis Eschenbach
July 22, 2017 3:24 pm

Willis fails again….
“In addition, there is a cycle which is three of the 18-year cycles, so it’s just over fifty years (54 years 34 days, if you’re interested).”

The Nodal tide cycle is 18.6 years, so please try multiplying 18.6 by three. The answer is 55.8.
..
http://geology.geoscienceworld.org/content/1/3/141
..
But seriously, there is no 50/54 year cycle. Three revolutions the minute hand on a clock is not one minute, it’s THREE.

Reply to  Willis Eschenbach
July 22, 2017 6:00 pm

“a short “Communications Arising” in Nature magazine?”

Congratulations on getting a comment published.

Maybe if you try real hard, you can get an article published.

Reply to  Willis Eschenbach
July 22, 2017 7:10 pm

Whoof…tough crowd.
Rob and Steve must be great fun at parties.

Reply to  Willis Eschenbach
July 23, 2017 12:02 pm

Thank you Willis for your link to Communications Arising.
..
I especially like this sentence: “Critical comments on recent Nature papers may, after peer review, be published online as Brief Communications Arising”

Please note I highlighted the most important word in the description for you. A “comment” is a “comment” even if it is “peer reviewed”

Reply to  Willis Eschenbach
July 23, 2017 9:11 pm

Wow, so your comment got cited?

It’s still just a comment. That’s what the link says……”Communications Arising” are peer reviewed comments.

Reply to  Willis Eschenbach
July 23, 2017 9:23 pm

PS, if it took you all that time effort and energy to get a simple comment published, can you imagine how many YEARS it would take you to get a real research article published in Nature?

Dr. Strangelove
July 21, 2017 8:06 pm

Rising sea vs. water pump. Pump won. Dutch drained the sea in Flevoland (1,419 sq. km.)
King Canute at work. Who’s laughing now?comment image

July 22, 2017 3:23 am

I suspect the difference is in how we account for autocorrelation. I use the method of Koutsoyiannis, detailed here. I don’t know how Tamino does it.
I think Tamino models the autocorrelation as ARIMA(1,1) noise.
https://www.researchgate.net/publication/265467321_Time_and_tide_analysis_of_sea_level_time_series

1sky1
Reply to  Phil.
July 22, 2017 2:20 pm

After modeling the sample autocorrelation as an ARIMA(1,1) process, Tamino proceeds with the quaint notion that geophysical power spectra need to be compensated for autocorrelation, akin to the compensation of confidence intervals for linear regression. Since the power density of a random signal is defined by the Wiener-Khintchine theorem as the Fourier transform of its acf, his ensuing chain of calculations and conclusions is inane.
Koutsoyannis fares scarcely better, because he posits an AR(1) process a priori as characterizing the acf, thus making it totally dependent upon the sampled value at lag one. This greatly oversimplifies most geophysical data, especially when wave motion is involved.
Acceleration is intrinsically a high-frequency phenomenon, since it is determined by the second derivative in the case of analytic functions. In the practical case of discretely sampled signals, its power transfer function is distinctly high-pass, being proportional to sin^2 in the baseband interval 0 to pi/2. If we are to discuss acceleration of SLR scientifically, an objective choice needs to be made for any smoothing to be applied to best display the salient signal characteristics. The smoothing supplied by linear regression over the length of available data does not meet that requirement.

Reply to  1sky1
July 22, 2017 6:52 pm

Oh, the “dazzle them with bullsh!t” approach, is it now?

Reply to  1sky1
July 22, 2017 7:06 pm

No matter how you slice it, or how many times you pass your high dollar value word salad through the vegematic slicer dicer, the Mark 1 eyeball still shows the truth, plain as daylight.
No acceleration is evident.

Reply to  Phil.
July 22, 2017 6:05 pm

Sorry that should be ARMA(1,1).

1sky1
Reply to  Phil.
July 24, 2017 12:25 pm

See the smoothed 15-yr rate of change of sea level:comment image
If there were no accelerations and decelerations, the plot would be nearly flat.
To rank amateurs, most scientific descriptions are just “high dollar value word salad.”

Kurt in Switzerland
July 22, 2017 5:11 am

Reposted from a comment to the Larry Kummer article from 20 July:
Perhaps the author(s) are unaware of the Gregory et al. assessment from a few years ago:
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00319.1
Abstract
Confidence in projections of global-mean sea level rise (GMSLR) depends on an ability to account for GMSLR during the twentieth century. There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction, and reservoir impoundment. Progress has been made toward solving the “enigma” of twentieth-century GMSLR, which is that the observed GMSLR has previously been found to exceed the sum of estimated contributions, especially for the earlier decades. The authors propose the following: thermal expansion simulated by climate models may previously have been underestimated because of their not including volcanic forcing in their control state; the rate of glacier mass loss was larger than previously estimated and was not smaller in the first half than in the second half of the century; the Greenland ice sheet could have made a positive contribution throughout the century; and groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude. It is possible to reconstruct the time series of GMSLR from the quantified contributions, apart from a constant residual term, which is small enough to be explained as a long-term contribution from the Antarctic ice sheet. The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.
Notice the final sentence. Such honesty is rare these days.

July 22, 2017 6:24 am

I’ve been having a running debate on this on Twitter with those who think there is acceleration. When I posted that not one surface station shows acceleration, the rebuttal from some is GLOBALLY together they show acceleration. So, 300 cars with a speed of 50kph collectively show an acceleration to 100kph, even though not one speedometer shows anything but 50kph. Got it.
Another demanded I show all stations to see there is no acceleration. I post a handful from around the world and state categorically that’s all I need to do to show not one station shows acceleration. That for there to be acceleration at some stations and not others would mean those with no acceleration are some how defying gravity.
Yep, in the world of AGW alarmists the laws of physics dont apply.
They also look for ANY acceleration at all, as if even a tiny little temporary acceleration is proof there will be a 2 meter rise by 2100. Again, this shows their complete lack of understanding and their desperation for anything to grasp.
To get to 2 meters by 2100 would require an acceleration (compound growth) of 3.7% per year. The least understood concept is compound growth. All compound growth has a doubling period. Each doubling period is the same as all previous doubling periods combined. This means that by 2099 sea level would have to be rising 8cm in that one year alone. Impossible.
Lastly, if you look at their graphs they show a rate of 1.7mm per year until 1990, then suddenly in that year, the rate of rise DOUBLED (100% acceleration) to a stable 3.3mm per year. No explanation how that could happen.
(I’d like to post some graphics, but have no idea how to do that, can someone post how, pls?)

Reply to  J. Richard Wakefield
July 22, 2017 1:14 pm

If you have a link that is a jpeg from a host website, just copy the web address on a separate line where you want the graphic.
You cannot post graphs you have saved on your computer…they have to be in the form of links to a website.
Or so I believe.
Up top, just below the site name, there is a row of tabs…one is to a test page…use it to test out what you want to do to see if it will work.
I am no eggspurt, but I know those few things.
As for sea level rise…the amount they claim is ludicrous…not based on evidence, just makin’ stuff up.
Many predict rates of rise that would rival meltwater pulse 1A.
Personally, I have mostly given up on arguing with people I do not know on social media sites.
It is truly pointless.
But sites like this and a few others are different…they are places that people can go for non-fake news, and false statements should not go unchallenged.
Even at congressional hearings run by guys like Ted Cruz, or news network programs like Tucker Carlson…many false statements go unchallenged, just slide on by, perpetuating all matter of *insert your favorite phrase for crap that aint true*.

Reply to  Menicholas
July 22, 2017 4:01 pm

Thanks, lets see if that works.comment image

Reply to  Menicholas
July 22, 2017 4:03 pm

It does so here is another. This is what surface stations should look like if the rate doubled in 1990:comment image

Reply to  Menicholas
July 22, 2017 4:06 pm

This graphic is common showing sea level rate accelerating instantly in 1990. With some comments I’ve added.comment image

Reply to  Menicholas
July 22, 2017 6:49 pm

Oh I get it…you hate children.
Why do you hate children?
/sarc off

Yawrate
July 22, 2017 7:47 am

I have perhaps a stupid question. Could not plate tectonics contribute to sea level variation?

Reply to  Yawrate
July 22, 2017 7:53 am

It does, which is why Alaska’s land is rising (sea level falling).

Yawrate
Reply to  J. Richard Wakefield
July 22, 2017 8:04 am

And what about those ever growing mid oceanic ridges?

Reply to  J. Richard Wakefield
July 22, 2017 1:19 pm

There are spreading centers, but also subduction zones.
Some seem to think Earth is expanding.
What it comes down to is, the total change in the level of the ocean over the past 150 years would not be even detectable if all you went by was pictures or where the beaches are.
Except for places where land has been displaced vertically by geologic forces, and where erosion has taken place…there is no place in the world where anyone could live in 1867 that they cannot live now because the ocean is too high. No one’s house has been flooded due to gradually rising oceans.
Storms…different story.

Prolefed
July 22, 2017 9:06 am

Has anyone applied ‘Tamino’s method’ to the UC satellite data record?

July 22, 2017 10:19 am

Whatever any future sea level acceleration turns out to be, it is very unlikely to put the Statue of Liberty underwater anytime soon …
As long as we don’t get any storms. Sandy closed Liberty Island for 8 months (75% 0f the island was flooded) and much of the infrastructure was destroyed. Here’s the dock before and after.comment image

Reply to  Phil.
July 22, 2017 1:21 pm

We will get storms. No matter what.
Did you have an idea that events which have always occurred can be stopped by political decree or virtue signaling obeisance?

Reply to  Phil.
July 24, 2017 7:08 am

Menicholas July 22, 2017 at 1:21 pm
We will get storms. No matter what.
Did you have an idea that events which have always occurred can be stopped by political decree or virtue signaling obeisance?

Flooding of Ellis Island and Liberty Island haven’t ‘always occurred’. Perhaps the rise in sea level there of a foot or so over the last century had something to do with it?

Svend Ferdinandsen
July 22, 2017 12:10 pm

You could use the Holgate-9 series of stations, as those stations are well known and spread around the globe.

Svend Ferdinandsen
Reply to  Willis Eschenbach
July 23, 2017 11:46 am

The best i can do is ask you to look at http://climate4you.com/
And specifically sea level and this one: http://climate4you.com/images/Holgate-9_Since1900-NEW.gif
It is mentioned which stations are used.
I belive it is the same stations all the time, so even if the rate could be a little different from other compilations, the change of rate must be usefull and valid.

Rob Bradley
Reply to  Willis Eschenbach
July 22, 2017 6:36 pm

1) ” that the longer cycle is about three of the 18-year cycles.”
2) “there is no Nodal tide cycle.”

Therefore there is no 54/55 year cycle

(basic logic Willie) …

PS, Google is your friend, I suggest browse the 1660 results you get for a search on “Nodal tidal cycle”

PPS, the solar system is darn good clock. We have things called “days,” and “years” based upon the clock like precision of the movements of the planets. The orbit of the moon is quite predictable.

Reply to  Rob Bradley
July 22, 2017 7:26 pm

Rob, if you read the post and the actual words Willis used, you will see he referred to the saros cycle, which is a period of 223 synodic months.
This cycles has been known since ancient times, and was what allowed certain cultures and not certain others to be able to predict eclipses.
Willis did not refer to the somewhat longer period known as the nodal tidal cycle. You seem to have translated one into the other inside your own head…those words are yours, not his.
BTW…223 synodic months is an interval known to great accuracy.
It is “approximately 6585.3211 days”.
Or, more simply, 18 years, 11 days, and 8 hours.
Three times that gives an even number of days.
And that three saros cycle period is exactly the number Willis cited.
I do not even have to break out my mark one pencil to do that multiplication.
Although I did do something you seemed unable or unwilling to do…I looked up stuff before I decided i was remembering correctly and criticized anyone.
You should try it sometime.
https://en.wikipedia.org/wiki/Saros_(astronomy)
https://en.wikipedia.org/wiki/Lunar_standstill

Rob Bradley
Reply to  Rob Bradley
July 22, 2017 7:43 pm

Menicholas: re-read the post, and focus on this: “Because the long lunar tidal cycle is just over fifty years”

See the word “tidal?”

You claim “if you read the post and the actual words Willis used, you will see he referred to the saros cycle”
….
Nope, he mentions that in a comment, but not in the post. Do you know the difference between the post, and the comments?

Reply to  Rob Bradley
July 22, 2017 7:53 pm

Ba-zing!
Ooh, you got me there!

Reply to  Rob Bradley
July 22, 2017 8:02 pm

I think it is worth noting that your rude comment was attached to his comment (did i use the right word…um, yup, I think so this time), not to the headline post.
Notice when you make a comment on a post, or on another comment…just what the little oblong button thingy says that you hit in order to …um…POST IT…says?
That one right down there on the bottom right as you POST your next rude-ass COMMENT to me.
See it?
What does it say?
If I had known this was grammar N@zi day, I would have peer reviewed each word of the comment I um…posted.
My bad.
So, your rude ass comment you posted in which you pulled the phrase no one else had mentioned out of your, uh, hat and attributed it to someone who had not said that…that was a reference to the top article?
But the words you quoted were not from up top.
So, like all warmistas…you just make crap up all day long.
It is like a reflex with you guys, aint it?

Rob Bradley
Reply to  Rob Bradley
July 22, 2017 8:12 pm

If you have a point, could you please make it?

There’s not much point in talking about sea level, which is measured with tidal gauges, and confusing it with an eclipse(s) that follows a saros cycle. Maybe you should direct your ire at Willis, since his sloppy writing and confusion about different cycles would best be solved with your help.

Reply to  Rob Bradley
July 22, 2017 9:01 pm

Just admit it…you did not know the difference between saros and nodal tide cycles. Or that there was one.
You conflated them and made a false attribution.
It is right there in black and white for all time.

Rob Bradley
Reply to  Rob Bradley
July 23, 2017 7:05 am

If it will make you happy Menicholas, I will admit that Willis did confuse the two.

Reply to  Willis Eschenbach
July 22, 2017 7:48 pm

“And the 54+ year cycle returns even more closely to the same point.”
I love this graphic animation, which illustrates the variation between one eclipse and the next one in that saros series:
http://eclipse.gsfc.nasa.gov/SEsaros/SEsaros136.html
Turns out NASA is still good for something.
A few somethings…just not anything related to climate.

Reply to  Menicholas
July 22, 2017 7:49 pm

Oh, wrong link.
This is the one:comment image

Reply to  Menicholas
July 22, 2017 10:19 pm

I do not know why it is that little square, but when I click on it I get the GIF from a wiki article.
it is the progression over one saros series of the path of each eclipse n the series.
Interesting pattern.
I wonder if each saros has a similar pattern?

Reply to  Menicholas
July 22, 2017 10:19 pm

Do you not see the GIF if you click the link?

crackers345
July 23, 2017 7:03 pm

Willis, to get the acceleration, did you remember to multiply the quadratic coefficient by 2?

Martin Smith
July 24, 2017 12:22 am

Willis, it looks like you have simply assumed that the 50+ year cycle you refer to has a significant effect on tides. I don’t think you have justified that assumption, so it looks like you have simply declared it so that you can ignore 95% of the 1,505 tide stations. Is there a paper that shows the effect of this cycle on tides?

Martin Smith
Reply to  Willis Eschenbach
July 24, 2017 11:26 am

I apologize for giving you that impression, Willis, but I was careful not to accuse you of anything. If you reread my comment, you will see that I did not accuse you. I said that your blog post “looks like” you are trying to ignore most of the data because you did not include the justification which you have just now provided. However, the word “lunar” does not appear in the paper you provided. The word “moon” does appear exactly once, and it does appear in the context of an 18.6 year cycle, but there is no mention at all of a 50+ year cycle, so you still have not justified your claim that this 50+ year lunar tide cycle is of significance. I’m afraid it still looks like you are trying to ignore most of the data. I’m not accusing you; it “looks” that way to me because I can’t see that you have justified your assumption.
But you are certainly wrong about your readers not having a clue what your motives are. We have all your blog posts.

Martin Smith
Reply to  Willis Eschenbach
July 24, 2017 11:51 am

From reading only two comments from me, do you really think you can reasonably make this claim?: “It looks like Martin Smith spends most of his time ignoring the truth and spreading lies”
You actually have not justified your claim that there is a 50+ year lunar tide cycle that has a significant effect on sea level rise. You haven’t done that, but your argument depends on it.

Martin Smith
Reply to  Willis Eschenbach
July 24, 2017 1:10 pm

>They say you need fifty years in order to get accurate estimates of “the tidal amplitudes and phases”
No they don’t.
I accept that you will not address the point I raised, so I will conclude by stating my understanding of your analysis: You throw out almost all the SLR data, and then you conclude from the remaining small fraction of the data that the SLR data do not show a statistically significant acceleration in SLR.

Martin Smith
Reply to  Willis Eschenbach
July 24, 2017 9:11 pm

Willis, here again is my understanding of your analysis:
You throw out almost all the SLR data, and then you conclude from analyzing the remaining small fraction of the data that the SLR data do not show a statistically significant acceleration in SLR.
You did throw out almost all the SLR data. That’s a fact. Did you conclude from analyzing the remaining small fraction of the SLR data that the SLR data do not show a statistically significant acceleration in SLR? Is that your conclusion, based on the data you analyzed?

Reply to  Willis Eschenbach
July 25, 2017 5:40 am

I’ve got an interesting debate going on at your friend’s site. Seems they dont like the fact that sat data shows a doubling of sea level in the 1990-1993 period and flat since. https://tamino.wordpress.com/2017/07/24/boston-sea-level/#comment-99191
Too bad you’re banned. Guess I will be too soon.

Martin Smith
Reply to  J. Richard Wakefield
July 25, 2017 5:46 am

J, why don’t you prove your claim (I think you mean doubling of sea level rise rate, not doubling of sea level) instead of just declaring it?

Reply to  Martin Smith
July 25, 2017 9:08 am

The doubling of the rate of rise, from 1.7mm up to 1990 to 3.4mm afterwards comes from the sat data. Surface station data shows no doubling. The sats are wrong.

Martin Smith
Reply to  J. Richard Wakefield
July 25, 2017 9:11 am

No it doesn’t, J. Tamino has explained where and why your claim is wrong. I won’t repost Tamino’s work here, but you now know why your claims are wrong, so it is really disingenuous to make the same claims here.

Reply to  Martin Smith
July 25, 2017 9:57 am

No he has not. He’s trying to shoehorn an acceleration curve onto a clear straight line data set. It is his OPINION that fits better than a straight line.
Here is the sat data, again. How you dont see a straight line is beyond me. Interesting how your side has turned into the deniers.comment image?itok=amqLr7zW

Martin Smith
Reply to  J. Richard Wakefield
July 25, 2017 10:40 am

J, the straight line you see is computed by simple linear regression. It always computes a straight line through any set of data. The straight line is the trend. There is always a straight trend line through the data. It is the trend. It always exists, but it says nothing about whether sea level rise is accelerating.

crackers345
Reply to  J. Richard Wakefield
July 25, 2017 11:07 am

Re: “the sats are wrong”
local sea rise from local gauges is contaminated by local changes in land height, which can be significant. sats are clearly superior.

Reply to  crackers345
July 25, 2017 1:15 pm

If they are superior, how come a calibration went unnoticed for 20 years? Sat data is rot with a lot of uncertainty and noise.
“In addition, the amplitude of the residual trend pattern is significantly lower than the expected error in trend patterns from satellite altimetry (in the order of 2 mm/yr to 3 mm/yr) and therefore suggests that satellite altimetry measurement is still not accurate enough to detect the anthropogenic signal in the 20 year tropical Pacific sea level trends. ”
https://tel.archives-ouvertes.fr/tel-01317607/document

Martin Smith
July 25, 2017 11:32 pm

“Sat data is rot with a lot of uncertainty and noise.”
Remember that, next time you tout satellite data as the best temperature data we have.

Reply to  Martin Smith
July 26, 2017 10:09 am

I’ve never relied on sat temp data. The only measurements I accept are the direct ones on the ground.

Martin Smith
Reply to  J. Richard Wakefield
July 26, 2017 10:15 am

Good for you. Then you know there was no “pause” or “hiatus” in global average temperature rise, and you know the global average temperature rise is accelerating.

Reply to  Martin Smith
July 26, 2017 11:36 am

And what is the rate of this acceleration? Do we expect the earth’s temp to double in the next few decades?
No, I dont see temps “accelerating” anywhere on the planet. If anything Tmax is down or flat:comment image

Martin Smith
Reply to  J. Richard Wakefield
July 26, 2017 11:48 am

I don’t know what your graph represents, J, because you don’t provide any links or citations. Clearly, it is not the global average temperature, which is what you and I are talking about. Apparently your graph shows the summer maximum temperature for somewhere. It says nothing about the global average temperature, which, again, is what you and I are talking about. Here is the complete explanation you are missing. It shows the global average temperature is rising, and the rise is accelerating. But no, I have not done the statistical analysis Tamino has done. The data are also available for each graph:
http://data.giss.nasa.gov/gistemp/graphs_v3/
And here is the statistical analysis by Tamino:
http://tamino.wordpress.com/2017/01/18/global-temperature-the-big-3/
So I say to you again: Good for you. Then you know there was no “pause” or “hiatus” in global average temperature rise, and you know the global average temperature rise is accelerating.

Martin Smith
July 26, 2017 9:03 am

Willis, won’t you answer my question? Here is my understanding of your analysis:
You throw out almost all the SLR data, and then you conclude from analyzing the remaining small fraction of the data that the SLR data do not show a statistically significant acceleration in SLR.
You did throw out almost all the SLR data. That’s a fact. Did you conclude from analyzing the remaining small fraction of the SLR data that the SLR data do not show a statistically significant acceleration in SLR? Is that your conclusion, based on the data you analyzed?

Reply to  Martin Smith
July 26, 2017 10:10 am

You have to throw out incomplete data, or records of too short a period. You cant include them because it incorrectly skews the results.

Martin Smith
Reply to  J. Richard Wakefield
July 26, 2017 10:17 am

I think we should allow Willis to answer for himself, J.

Reply to  Martin Smith
July 26, 2017 10:13 am

For example, in Canada only 13 stations in the Environment Canada’s database have a complete record of temps going back to 1900, even though at the height EC had 1300 stations in the mid 1980s. Now they are down to less than a third of that. Hence when looking at an as complete record as possible one can only use the 13 stations.

Martin Smith
Reply to  Willis Eschenbach
July 26, 2017 9:47 pm

No, Willis, not the “same” noise issues, different noise issue. But yes, all satellites face noise issues. The noise issues for “passive microwave reading satellites” are probably worse, yes? Multiple altitudes; multiple frequencies; clouds… That’s harder than bouncing radar waves off the ocean, isn’t it? Clouds don’t bother radar so much, do they? And there is only the one sea level to measure. There waves and wind conditions, of course.
But let’s return to our discussion. Will you answer my question? Here is my understanding of your analysis:
You throw out almost all the SLR data, and then you conclude from analyzing the remaining small fraction of the data that the SLR data do not show a statistically significant acceleration in SLR.
You did throw out almost all the SLR data. That’s a fact. Did you conclude from analyzing the remaining small fraction of the SLR data that the SLR data do not show a statistically significant acceleration in SLR? Is that your conclusion, based on the data you analyzed?

Martin Smith
Reply to  Martin Smith
July 26, 2017 11:50 pm

Willis, you wrote: “…but that doesn’t mean that all satellite datasets are equally bad as you are claiming.”
I did not claim that. In fact, I claim the satellite datasets used for inferring temperature are much more noisy than the satellites used for measuring sea level. I don’t know for sure, of course, but doesn’t it seem reasonable given the more complicated problem for inferring temperature from irradiance data measured at different frequencies for different altitudes, and given the problem of clouds getting in the way?
And now you write: “I already answered that, perhaps you weren’t paying attention.”
No, you didn’t. Will you answer my questions? You throw out almost all the SLR data, and then you conclude from analyzing the remaining small fraction of the data that the SLR data do not show a statistically significant acceleration in SLR.
You did throw out almost all the SLR data. That’s a fact. Did you conclude from analyzing the remaining small fraction of the SLR data that the SLR data do not show a statistically significant acceleration in SLR? Is that your conclusion, based on the data you analyzed?

crackers345
July 26, 2017 10:45 pm

willis, when you did a rank2 polynomial
fit, did
you multiply the quadratic coefficient
by 2 to get the acceleration?

crackers345
Reply to  Willis Eschenbach
July 26, 2017 11:51 pm

thanks; for some reason
that reply didn’t reach me;
or I
missed it. cheers willis.

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