Finalizing step one on the sea level

This post may update as more information becomes evident.

Well, I’ve got all the data on a spread sheet from PSMSL tidal gauges.  To review, I’ve used only stations that didn’t have more than one year missing from the annual data from 1981-2008.  Originally, I wanted the last 30 years.  1981-2010.  Sadly, the coverage sucked, so I moved back to 2009.  The coverage was still lacking so I moved back to 2008.  The coverage still sucks.  Each point represents a tidal gauge. (the colors are vaguely associated with coastal codes.)


There are 177 individual stations.  PSMSL divides the stations up by a coastal code(henceforth referred as CC).  I don’t agree with the way they’ve divided the data, and will come up with what I believe will be more appropriate.  Of the 177 stations, there are 43 PSMSL’s coastal codes are represented.  When viewed using the CCs, the mean is 2.016mm/yr.  However, some of the CCs are only represented by one tidal gauge in the data set.  14 to be precise.  And some of them are pretty dubious.  For instance, POTI (lol, no I didn’t make that up) lat 42.16667 long 41.68333 is reporting an improbable 10.34mm/yr rise.  That’s one of the blue pushpins at the east of the Black sea, in the nation of Georgia.  Oddly, PSMSL doesn’t include the other location on the Black sea as the same CC, I will, thus it will decrease the weight of the POTI gauge if I find more gauges in the same coastal area.  The other gauge to the north is TUAPSE, a part of Russia, less than 200 miles away, which reports a rise of 4.19mm/yr, which is still quite high for the data set.  The points on the coasts of Australia are oddly lumped into the same CC, which I would think it should be divided by the east/west locations.  But either way, they come in under 2mm/yr rise, as does Hawaii. 

Probably just coincidence, but the recent blathering about pH levels followed a line from Hawaii to Alaska as part of the study.  Hawaii comes in 1.76mm/yr, but the coasts of Alaska with 7 data points comes in at -5.74mm/yr.  Warming salt water expands, but it also outgases CO2, while cooling contracts while retaining CO2……. correlation?  The entire NA west coast shows a decrease in sea level with a CC average of -2.64mm/yr.  The NA east coast shows a rise of 3.5mm/yr, (there are questionable locations) but the entrance to the St. Lawrence shows a -5.2mm/yr.

Another interesting coincidence.  The insidiously vapid thought behind the Glacial Isostatic Adjustment originated in Scandinavia.  There are 3 different CCs in that area.  CC 40, 50, and 60.  Respectively, their rates of rise are -0.05, -1.88, and -3.88mm/yr.

Some more thoughts…….. obviously, there isn’t enough information to state one way or the other about sea-level rise.  But, what we can say, is that based on this information, and the prior update on this issue, there isn’t anyway some pinhead took an unbiased view and determined a 3mm/yr rise in the sea levels.  But, I’d like to come up with a reasonable number based on observed data.  I believe I can get more data points by shortening the time frame, but I’m not sure about how diverse the locations would be, and that’s what I’m looking for.  I suppose I could seek out the various locations and come up with a reasonable criteria and then fit the rest of the data to that criteria.  I’m not sure.  Do you guys have any thoughts on this?  I really want this replicable and unquestionably unbiased.

Another thought I had, was to divide up the various coasts, determine an average rate per coast and factor in miles of coast line.  I’m also about to look through the notes on each gauge.  PSMSL does a nice thing and has the notes directly referenced to the station ID#, so, while it will be tedious, it won’t be difficult. 



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5 Responses to Finalizing step one on the sea level

  1. Nice work. Thanks for this post.

    For the “sea level rise” issue on the North American MidAtlantic east coast, there is:

    (1) Glacioisostatic adjustment. It is very VERY significant in sinking forebulge regions like the one in which I reside.
    (2) Subsidence (both from aquifer depletion, as well as a 35 million year old, 50 mile wide crater beneath the mouth of the Chesapeake Bay.
    (3) Unexplained tidal floods which may or may not be related to changes in the NAO or some other teleconnection shift in the means over time.
    (4) Changes in the Gulf Stream. Just like that overactive jet in your swimming pool, it changes the mean level of the water surrounding it.
    (5) Tide gauges “anchored” on “nothing”….silty riverine sediments and clays on a squishy coastal plain with no geologic instability other than that.

    Norfolk, VA, USA

    • suyts says:

      Thanks Chris, yes, there are several sites on the Atlantic coast that are in questionable locations. If I ever get to a point that has decent global coverage, then I’ll start working on eliminating some of the sites that are in river deltas and effected by some of the reasons you listed.

      Thanks for popping by!


    • Mike Davis says:

      Hi Chris! It is good to see a familiar name!

  2. Mike Davis says:

    The US is tipping over and the pivot point is Great Bend Kansas. If the trend continues San Fransisco will be at a higher elevation than Denver in only a few M years! Of course the Golden Gate Bridge will be in Alaska by then and LA will probably be on an island off the Oregon Coast. People adapt to many things, even living on a vibrator. Maybe that is causing the Left Coast attitude!

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