Food For Thought —- NOAA’s Tidal Gauges — SLR Not Accelerating


Well, if the left wants to give talking tips for Christmas dinner, why can’t we?  So, after you’re done making fun of the obnoxious fellow or gal expressing outrage that an old Christian guy from the south believes homosexuality is a sin, and if the conversation is becoming tiresome, you can always change the subject to climate and our sea levels, and make fun of the obnoxious fellow or gal all over again!  (Be sure to do it in a nice, kind, gentle nature!!!)   

So, Steve has an interesting post up at Real Science.

Average Sea Level Rise Rate Is 0.9 mm/year

He notes NOAA has been playing with some tidal gauges from PSMSL, and applying their analysis to them. 

So, I thought I’d play, too! 

The gauges which NOAA is playing with are long-term gauges, in that they cover on average about 71 years.

As we all know, the tidal gauges aren’t uniform in the time periods they cover, which makes for some arbitrary decisions when trying to evaluate the data.  But, in this case, more my purposes, NOAA makes it pretty easy. 

We want to determine if the sea level rise is accelerating or not.  Steve finds that the rate of rise has been 0.9mm/yr, but, I want to know if the quickening to our impending demise has started or not!!!

Of the 241 gauges NOAA is playing with, 42 of the records end prior to the year 2000.  The average length of time they cover is 59 years.  NOAA is also playing with some with the last years still being current (through 2011).  There are 103 of them and they average about 76 years in coverage.  In other words, from 2011 going back the average start year is 1936.  The average start year for the gauges which ended prior to 2000 is 1931. 


Note, the locations on the bottom axis does not list all of the locations. 

For tidal gauges, this is just about as good as one can hope for!  Clearly, this won’t be exacting, but, we can get the average SLR for the gauges ending prior to 2000 and the ones going through 2011 and determine if the rate of rise is increasing or decreasing! 


Gauges ending prior to 2000 averaged a rate of rise of 1.47 mm/yr.  The ones current through 2011 is 1.14 mm/yr. 

I would note that these results are pretty consistent with what Hank found in his examination of Beenstock et. al

Just some to wow and impress your friends and family as you rebut the obnoxious lefty of the group. 

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18 Responses to Food For Thought —- NOAA’s Tidal Gauges — SLR Not Accelerating

  1. HankH says:

    Good work, James. I’m pleased to see that you got similar results.

    I’ll take the tide gauge network data any day over satellite data. It’s the kind of difference between using a tape measure to directly measure you waist size vs. estimating it from a photo taken 1,800 miles away. If I were a tailor, I’d prefer the the tape measure results to tailor your suit.

    I’m also pleased that science is taking more interest in the tide gauge network and pointing out the marked difference between its measurements and the satellites.

  2. Lars P. says:

    Well I understand the problem with satellites measurement is they are calibrated on some tide gauges.

    So would guess the problem starts from the way this calibration has been done some time ago:
    If you go at the old John Daly site there was one satellite sea level grow 0.9 +-0.2 mm/year:
    see also:

    “The TOPEX-Poseidon project has also established a set of tide gauges on islands in the Pacific Ocean fitted with GPS equipment, the purpose of which is to calibrate the satellites to a greater level of accuracy.”

    Which was later calibrated & adjusted – see here a nice summary (sorry german, but a nice summary with the old and new “calibrated” chart included):
    “Wir mussten das machen, ansonsten hätten wir ja keinen Anstieg”
    translates like: we had to do it else there would have been no sea level rise.

    So the real question might be how was this initial calibration done which subsequent was the source for all post adjustments/calibration which obviously differ from tide gauges message.

    Well this my 2 cents. And a small bonus – not sure you have seen the ship stuck in the antarctic ice story:–abc-news-topstories.html
    “The ship cruised to the site of a 1911-1914 expedition of British explorer Sir Douglas Mawson”, maybe there was a bit more ice there now then in 1911 🙂 .

    • Lars P. says:

      James, if I correctly remember you looked once a bit more into sea level rise story.

      The satellite measurement are calibrated against tide gauges.
      Also explained here:
      “We do calibrate the altimeter sea level measurements against a network tide gauges to discover and monitor drift in the satellite (and sometimes tide gauge) measurements.”

      Do you know more or have somewhere some link from somebody who has looked at what tide gauges have been used and how the calibration has been done?

    • suyts says:

      Hmm, I seem to recall where I saw a few of the stations noted, but, I don’t have a link handy. I’d have to do some digging to find it again. You’re right, we did dig fairly deep into the subject. As I recall, I stopped digging when they just started to arbitrarily change the data, especially the satellite data. Personally, I don’t believe they’re calibrating their data to anything. I believe they have a predisposition as to what the data is suppose to show and adjust accordingly. ……… I started with Aviso …….

      Okay, Lars!!! You did it to me! 😀 I went to look. I think what you’re looking for, at least to get you started is here here …. and here …..

      They all have interesting information and links ….. which can take you on quite a journey. But, it does give me an idea for a post in the future.

      • Lars P. says:

        He He 🙂
        Happy New Year James!

        Thank you for the answer!
        Actually not sure it is worth looking into it, as in the end this should solve by itself, whereas looking might be very complex… If there is a bias in estimation the difference to reality should grow and grow with discrepancies that cannot be ignored.

        If there is some error hidden into it it might be done somewhere around 2003 when this:

        became this:

        what made Mörner to comment here:

        Click to access Morner.pdf

        one interesting point that Mörner mentions is:
        “This shows a rise from 1830-1840 up to 1930-1940 of 11 cm. In that 100-year period, the Earth’s rate of rotation decelerated at a value which corresponds to a 10-cm sea level rise (see, for example, Mörner 1996)”
        Wow, not sure if the rate of the Earth rotation can be measured with such a precision, but if it the case that is an interesting way to double check the current sea-level rise – according to the satellite we should have some 5 cm sea-level rise, can we see a corresponding deceleration in the Earth rotation?

        • suyts says:

          Yeh, it’s a pain to sift through. Happy new years to you to Lars!!!!

        • DirkH says:

          Lars, it’s simply Length of day (LOD), and LOD is determined largely by the pirouette effect (If masses are closer to the centre, Earth rotates faster). LOD can of course simpley be measured to any accuracy desired with an atomic clock and astronomical observation of stars to have a reference point.

        • Lars P. says:

          You are right. Was just wondering if we have these historical values so precisely measured.
          Found something at WUWT:

          however there is no mention with the sea-level rise. As you say – and as per Mörner – it makes sense to have it related to the sea level rise.
          Looking at the graph it seems to fit to the temperature chart – warming in the 30th, with a cooling 1940-1970 and subsequent warming, where warming is sea level rise & rise in LOD and cooling is glacier advancing – sea level contraction and reduction in LOD.
          Would be interesting to have the math exercise done to see what sea-level rise-contraction & expansion does math foresee for the respective LOD variations – it must be a relative “simple” rotation energy calculation.

          I would think the correspondence to other atmospheric processes is only indirect, as long as warming – sea level expansion – and the reverse has a correspondence with an atmospheric process.
          All these could be compiled in a nice post James, what do you think?

        • Lars P. says:

          Hm, just wondering if I am not reading the graph upside down like somebody did with the “Tiljander”?

        • DirkH says:

          “Would be interesting to have the math exercise done ”

          Did you ask around at Tallbloke’s? They’re the cyclomaniacs and curve matchers (no offense. Just as good an approach as any other if it drives new explorations.)

        • Lars P. says:

          Hey Dirk, Good point. I tried here:

          Lets see if they have done any investigation so far.

        • Lars P. says:

          Lol, interesting subject. As I had some free time I was a bit ruminating these days about it. Still wondering further how good are historical LOD values determined.
          Here some further musing on the recent values:

          The 1993 to now+ values (coinciding with satellite measurements of sea level rise) show a reduction of about 2 miliseconds in LOD.

          Was thinking at what could be the explanations for it. I came with 2 potential explanations:
          1) The sea level rise shown is wrong and we have in reality a sea level reduction instead of a rise. this would mean that more ice captured at the poles, especially in the Antarctica, and totally wrong model showing expansions of the seas (any Antarctic ice loses are due to adjustments actually, if I correctly remember GRACE measurements show increase in mass, but the models assume raising ground.
          This explanation does not seem to fit with tide gauges measurements, (not sure how these are adjusted and calibrated… but assuming this is still not done)

          2) It may be that LOD variations – at least in this period – are not due to any sea level rise which is not significant enough at least less then other influences. See also:

          So if other reasons have caused the LOD 2 milliseconds reduction, a faster speeding Earth could create a certain sea level rise through global redistribution of the seas – which would show sea level rise towards the equator and lower levels towards the poles.
          This would be showing additional rise in the area measured by satellites.
          And this is also what tide gauges actually measure by the tide gauges and may be part of the assumed local elevation values (if there have been any increase in such measurements).
          Ok, maybe this is also shown by tide gauges as here:

          but may be also variations from other cycles.

          Anyway, these my musings, not sure if it is consistent enough to give you the idea for a post on the subject? Also not done any calculations, just wild speculations so far…

  3. DirkH says:

    Here’s a lecture by Chris Essex about problems in climate modeling. Haven’t seen this before, send it to anyone who still believes the models are capable of predicting anything.
    “Believing Six Impossible Things before Breakfast, and Climate Models”

    • Me says:

      Nice, but like Chris at the end, they have too much invested in this and when they finally let go they will come up with some new madness.

  4. philjourdan says:

    It is the same with temps. We will be setting record highs as we freeze to death. And we will be drowning in sand on the shores that just are not disappearing.

  5. Roger Andrews says:

    A few years ago I constructed a global sea level time series from 382 PSMSL tide gauge records. I didn’t adjust any of them, so the series will show sea level rise relative to the global coastline rather than absolute (or geocentric, or eustatic) SLR. According to my results sea levels have risen by only about 100mm relative to the global coastline since 1900:

    The reason the IPCC gets almost 200mm (AR5 fig 3.13 (a)) is that it applies vertical land movement adjustments to the tide gauge records to obtain what it contends is a record of absolute SLR. There are, however, some doubts as to how realistic these adjustments are.

    • suyts says:

      Roger, thanks for the contribution. Sorry about the wait. I forget to check regularly for new commentators. You’re approved now and won’t have to wait in moderation….. two link limit.

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