Guest Post by Willis Eschenbach
A reader who posts under the name “tokyoboy” sent a link to a very interesting sea level record from the Japanese Meteorological Agency. It covers the period 1906–2010, and when I first saw it I thought they’d made some mistake.
So I got their data, and plotted it up. I also got the satellite records for the area. Finally, I got records of one of the sites that the Japanese used, but I obtained it from the PSMSL records. All of them agree very well, so I am forced to assume that there are no obvious errors in the Japanese records. Figure 1 shows the results:
Figure 1. Japanese sea level records. Two records marked “Japan” are from the citation above. They are averages of long-term records since 1906 (4 sites, blue line), and shorter-term records since 1960 (16 sites, red line). Satellite records (green, 1993-2010) are from the University of Colorado interactive wizard. Wajima records (purple, 1930-2010) are from the PSMSL.
You can see why I thought there was a mistake. Sea level around Japan rose steadily from 1906 to 1950. Then it dropped for fifteen years and bounced around until 1980. Since then it has risen again, but it is about 20 mm lower than it was in 1950.
Now, I can’t find anything at all wrong with the data. The satellite record agrees with the Japanese averages, as does the PSMSL record. So we have to assume it is accurate.
But it is unlike any record I’ve seen of the global average change in sea level. That global record climbs steadily over the century.
I’m happy for suggestions and comments, as I’m in mystery over this one. It’s one of the great things about the climate, always more puzzles to solve.
w.
This merely illustrates a point I have tried to make quite a number of times in comments here. Most post and comment discussions on this topic are derailed from the start because they are based on the implicit fallacy that the seas are actually level i.e. that the massive waters of the world’s ocean’s will respond like a cake pan filled with water on your kitchen counter. The sea level anomalies in the satellite altimetry record bear almost no relationship to anything real on the planet and any changes in GMSL they suggest will never be mirrored by similar changes at any particular point on the planet, except as a matter of happy coincidence.
Those satellite anomalies are calculated in reference to the relationship between the Geoid, a completely artificial and abstract approximation of what the equipotential surface of the world’s oceans would look like if every influence except changes in the gravitational strength of planet were removed and all land masses were made completely permeable to them, and the reference ellipsoid, a mathematically smoothed approximation of the squashed and lumpy spheroid that we inhabit. The baseline for the anomalies is the difference between the undulations of the Geoid, and the reference ellipsoid, which BTW range over about 200 METERS!
http://en.wikipedia.org/wiki/File:Geoid_height_red_blue_averagebw.png
I have recommended that people interested in this topic invest the time necessary to study this document
http://www.nodc.noaa.gov/sog/Jason2/userhandbook_4.pdf
OSTM/Jason-2 Products Handbook
Even if you only do a superficial scan, try to keep a tally of the number of adjustments, correction factors, and various kludges involved in the process and, given that almost all of them are at least partially and often completely based on models themselves, the possibly hundreds of opportunities for human influence to intervene.along the way
Pay particular attention to
2.3.1. Accuracy of Sea-level Measurement
Generally speaking OSTM/Jason-2 has been specified based on the Jason-1 state of the art,
including improvements in payload technology, data processing and algorithms or ancillary data
(e.g: precise orbit determination and meteorological model accuracy). The sea-surface height shall be provided with a globally averaged RMS accuracy of 3.4 cm (1 sigma), or better, assuming 1 second averages.
And also the error budget table that follows, including the line for significant wave height error.
And bear in mind that the JASON 2 is the latest and greatest of these wonderful devices and, given the significant upgrades to orbital precision and realtime atmospheric corrections, is probably 2-3 orders of magnitude better than the earlier TOPEX/ POSEIDON units from the beginning of the record.
Sea levels are very difficult to measure, and satellite data is all about adjustments.
The Japanese agrees better with Moerner’s view and his data:
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
Plenty of non rising sea levels:
http://www.john-daly.com/ges/msl-rept.htm
Some features of the University of Colorado tool might shed some light on this.
Choose the Variance option, and it looks just like an El Nino map in many ways – the equatorial variance primarily – and what I’m not used to seeing is the “extra angry” red that appears to be blowing into Japan. Perhaps someone with experience in seasonal wind patterns could provide input on that, or maybe this could: http://www.youtube.com/watch?v=bQOJwDMZMXw
It would be interesting to see a combined plot of different variables, PDO, temp anomaly, pressure, etc. I vote for Global Sloshing.
I’m sure that the explanation will be that this is more proof of AGCD, since the land is obviously rising due to the missing weight from the melted glacier and snowcaps. 😉
More seriously though, is there any correlation obvious with earthquake activity? Also, we have to remember that the earth’s crust isn’t a uniform sphere, isn’t a static shape and subtly deforms due to gravitational influences as well as atmospheric and tectonic action. Correctly accounting for those factors when measuring sea level is (IMO) virtually impossible without having at least: 1) A dense global mesh network of sensors accurately calibrated to a common zero; 2) Consistent, accurate satellite measurements; 3) A much better understanding of the effect solar system gravitational interactions have on plate tectonics; 4) An accurate measure of the volume of Earth’s water broken down by phase state (ice/vapor/liquid).
climatereason says:
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Hi Tony
For your attention and mine amusements I have added (see the lower graph) what the Tokyo tectonic oscillations might have looked like in the past centuries.
http://www.vukcevic.talktalk.net/JMF.htm
Willis, I have seen other records showing declining seal levels in some places, inclining sea levels in other places, and little to no net change in other places. If you’d like I’ll start tracking them down and sending you links, though it may take me a while. It’s possible that my memory or my sources are mistaken, the usual caveats. If you have an interest, please email me. You have my email.
As with the heat and other energy, the changes in the sea levels are known to be non-uniform over vast regions. You have one example here.
How do they calibrate the satellite data ? I know they don’t use a tape measure, but what is the sea level calibrated to ?
Willis,
Try googling “plate tectonics”. There is a surprising amount of movement in most parts of the globe both laterally as well as vertically.
For example, the Himalayas are the result of uplift due to plate tectonics, as any geologist can affirm. These effects can be of the order of a decimeter per year.
As mentioned above, I think it shows a strong correlation to the PDO cycle with a 5-10 yr lag time.
One should be able to marry up the two graphs, i.e. the Global Sea Levels graph is implicitly superimposed on any local movement of the soil.
As the Japanese sea levels went up or down 2 cm, and the global sea levels steadily increased by 20cm in the same timescale of 100 years, taking both graphs as true, one has to assume that Japan as a whole steadily rose by 20 cm, give or take 2 cm here and there.
As Japan is a geologically unstable region, I suspect (and I am not a geologist – I am a chemical engineer, so could be wrong) that some parts of the country would sink, and some would go up, and some would go up and down, perhaps more than once. Just as their graph shows.
I remember reading, Bob Carter, I think, saying that there is no such thing as Global Sea Level, only local ones.
Therefore I think, on the balance of things, is that the Global Sea Level graph has been cooked, and the Japanese graph is true.
Mike Pickett: it would be very interesting to run a Fourier analysis of the curve, because I think I see at least one periodic function in it.
Every short time series has at least one periodic component in it that can be seen. Unless there are multiple cycles with the same period, it is almost impossible to discern whether the periodic function relates to any sort of other periodic oscillation or is random.
It’s a gravity thing.
I think it’s pretty obviously due to ‘buoyancy’, Archimedes Principle and the chinese population explosion. More chinese equals more weight on china, equals more downforce on the molten mantle – equals uplift in Japan…./sarc off
mind you, long term axial inclination and orbital/gravtitational variations could also contribute via global sloshing…………!!!
Willis: At a guess, I would say the Japanese sea level is tracking global temperature. A rise from 1900-1940, then a fall to 1970-1980, then a rise, then it levels off the last decade or so.
Sea level isn’t “level” at all, but is set by the height of the Geoid :
http://en.wikipedia.org/wiki/Geoid
In a highly tectonically active region like Japan, it may be possible that the density of the underlying mantle can undergo rapid changes which alter the gravitational force acting on the sea surface, thus changing its’ height…….
Gravity. Is there anything it can’t do? (:-
Seriously Willis, have you checked other stations around the Pacific Rim (the Philippines, New Guinea or Indonesia may be a good place to look) to see if similar effects manifest themselves there.
I get a feeling that it has somthing to do with ocean temperture or slight changes in currents pushing water a little less towards the coast just as when it windy but with a much smaller effect.
Sine we are just talking about rather small changes there may not need to be any larger longterm changes in currents to change the level at thre coast 10-20 mm.
It tracks the Japanese economy. When Japan is depressed, the measured sea level rises.
Missed one thing, the wind.
Could there be a long term change in wind speed and does the data have a adjustments for longterm changes in wind speed? Considering the PDO etc and that Japan is in the Pacific, changing average wind speed piling up a little it more water on average along the coast could be a reason.
I’m betting any individual location will look similar, going up and down over time. It’s only when you add all of them together and divide the count, that you get an interesting but not useful value as a result.
For the location of Japan, wind (and perhaps currents) seem the obvious answer.
This fifty year oscillation looks a lot like it is coupled to the recent PDO. Remember that a 1 mbar barometric pressure change will cause a 10 mm change in sea level, so about 6 mbar average barometric pressure swing between Japan and the Pacific over this period would do the job. I think that this is comparable to the pressure swings seen for the ENSO index, (derived from the average barometric pressure difference between Darwin and Tahiti).
You would have to imagine that the absence of a significant long term trend would be due to local tectonic uplift.
This link from Wired Science, 2009 describes an event on east coast of USA:
From Maine to Florida, the Atlantic seaboard has experienced higher tides than expected this summer.
At their peak in mid-June, the tides at some locations outstripped predictions by two feet.
The change has come too fast to be attributed to melting ice sheets or anything quite that dramatic, and it’s a puzzle for scientists who’ve never seen anything quite like it.
June was — high tides aside — “nothing to write home about” in Trenberth’s estimation.
“It’s a bit of a mystery,” he said.
http://www.wired.com/wiredscience/2009/07/hightides/
Even though this is tsunami related, the stones positions might tell part of the story:
The stone tablet has stood on the forested hillside since before they were born, but the villagers have faithfully obeyed the stark warning carved on its weathered face: ”Do not build your homes below this point!”
Read more: http://www.smh.com.au/environment/tsunami-warnings-carved-in-ancient-stone-20110421-1dqmt.html#ixzz1l4cue6z7
This comes as no surprise to me as both in Sydney (Australia) at Lady MacQuarie’s Chair and at Hobart the old Tide Level Markings made in the 1820’s are still in use and quite correct. These are both seismically stable areas of sedimentary rock in which the marks were carved.
Someone asked for spectrum, I have added one:
http://www.vukcevic.talktalk.net/JMF.htm
Stronigish ~60 (61.08) year component, I suspect some readers may be very happy about that.
@ur momisugly Tony Brown
I really enjoyed reading Sea level changes from the Holocene to the Romans. Where do I find parts 2 & 3?