As we surmised in earlier posts, the crozon.colorado.edu website was a test run. Here’s the newest graph from the revised http://sealevel.colorado.edu/
They write about the update:
Welcome to the new webpages from the University of Colorado sea level group! We apologize for the delay in updating our sea level releases, but the transition to these new web pages took longer than we thought. In addition, we have made many improvements to our data (new orbits, new tide model, new corrections) which ultimately had little effect on global mean sea level, but brought us up to date with the latest advances in the field.
One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land. Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.
You may also note that rate of sea level rise over recent years has been less than the long-term average. This is believed to be due to the recent La Nina’s we have been experiencing, though research on this is continuing. We will soon add a plot to the web site illustrating this effect.
Let us know if you spot any bugs in the new web pages. Thanks for your interest!
Comments welcome.
Why don’t the scientists also calculate a Global Mean Coastal Level (GMCL) to compare to the GMSL? Or even better, show the specific points where coastal ground elevations are stable, and then show which other areas have land that is rising versus where the land is dropping in elevation. Then compare global or local sea level variations against land levels. The eggheads have tide gauge data plus satellite info (Jason, Topex, GRACE, GPS, yadda, yadda). How hard can that be?
Also, if La Nina’s drop GMSL levels, then El Nino’s raise GMSL levels, right? But if these trends just reflect upwelling of warm/cold water to the surface, how does that change the net ocean density and thus the net ocean volume?
And we now know that isostatic effects have overestimated the amount of melt water from Greenland and the West Antarctic Peninsula so that scientists now have to admit that any melt water contributions to GMSL have been, well, overestimated.
And next we hear that massive fresh water impoundments have prevented GMSL from rising as much as it would have otherwise. But we also now hear that massive acquifer depletions are forcing the GMSL to rise faster than it would have otherwise. Why don’t the eggheads do a mass balance for these two effects? Or can they?
Last, the GMSL has risen about 7 mm in last 4-5 years, or about 1.40-1.75 mm/year. That’s a helluva acceleration from 3.1 mm/year. Oh, wait – that’s not an acceleration, is it?
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
What strikes me is how the “adjustments” are always upward, NEVER downward.
Some useful information and illuminating diagrams on Mean Sea Level and its significance for surveying in Canada : http://www.geod.nrcan.gc.ca/hm/msl_e.php
I note MSL levels referenced to satellite defined datum vary +or – 2metres over the globe. Does the ocean surface topography meander around in the short and long term?
I feel quite queasy!
Re. Climateforall at 1:49: So do you think this is a permanent decline? It’s done this before and it always goes back up. I’d laugh as much as anyone if sea level went down, but I sure don’t expect it, and if it happens it might mean the deep freeze is upon us. You probably don’t understand anything about the LOD problem, so I’d advise you to look it up. LOD sets constraints on possible sea level rise; repeated claims of recent tripling not only fly in the face of the sea level data, but they fly in the face of LOD. The earth can’t be speeding up while ice is melting at catastrophic rates.
Pass the binky? –AGF
What do real sea-level-rise scientists have to say about this computer model showing a trend of rising sea level?
Nils Axel Mörner is a geologist who goes out to measure actual sea level rise , or the lack of it, instead of peddling “snake oil” computer models.
As can be seen from this link, already in 2007 Mörner stated there was no sea level rise whatsoever. He has also pointed out the the computer models used by IPCC and fellow travelers are operating with “adjusted data”, justifying this by saying “otherwise we cannot get a trend of rising sea level”. A quick Google search shows that Mörner today confirms there is still no trend of sea level rise.
So why should we take this computer model from the Uni of Colorady seriously at all?
So the data are no longer actual measurements. They have been ‘adjusted’ upward to account for glacial rebound, or something that sounds really cool and requires a few PhDs to understand. I can think of reasons to adjust the data downward, such as silting and fresh water aquifer draining, but that won’t make it look scarier.
I get really tired of government agencies adjusting what previously were actual measurements.
David Burton already beat me to determining MSL, using existing tide gauges.
Thank goodness. It would have taken me months to do the calculations.
0.61 mm/year.
Though before we get our hopes up, RealClimate already “debunked” him, saying that his calculations are not peer-reviewed and doesn’t take into account GIA.
In regards to tide gauge mean sea level averages, what purpose does it serve to include an adjustment for GIA?(rhetorical)
Tide gauges are one dimensional readings though. Simply height.
GIA is about 3D volumetric displacement of land mass, due to uplift from ice sheet loss, and giving a value to correct a means for that displacement of land mass.
So while we’re at it, lets adjust for subduction, sinkage, sea wave erosion, lava buildup, island construction(my favorite), and any other phenomena that adjusts the height of any given tide gauge.
We can’t though, because each tide gauge is not affected by one or more phenomena that another tide gauge might be affected by.
That is why the GIA correction can only be applied to satellite altimetry data.
This only allows the alarmist community to confuse the issue, using convoluted models to support their propagandization.
The actual, physical observance of existing tide gauges the world over show only a 0.61 mm/year rise in the historical registry.
Which leads me to wonder where all that rise is hiding at.
If we don’t see any physical evidence at known tide gauge sites, then all the rise must be happening wherever man is not present.
Those 50 mile long, remote, uninhabitable beach fronts must be 10 feet under water right now.
I think this is what the bottom line is all about:
Rate of change plot before and after.
Taking the slope across three data points (d/dt) and fitting a straight line to the whole record we see where the difference lies. GIA assures that there is an ever mounting sea level. The non-adjusted data shows sea rise would stop around 2024.
Now I’m not suggesting that fitting a straight line is particularly meaningful, nor that there is any reason to say that is a trend that will continue. But if someone wants to play “if the current trend continues and we fail to act to stop CARBON emissions NOW ….” they will want their data to show continued rising sea levels not a trend showing it will stop in ten years.
The rate of change plot shows the differences in the new data that are not obvious in the straight difference Mike Jonas provided here : http://members.westnet.com.au/jonas1/ColoradoUniDiff.jpg
A G Foster says:
May 6, 2011 at 1:49 pm
Right, so if that’s what you are trying to work out, *one* of the things you need to know sea level. If you want to know total mass or total volume you have other things to look at and the result will NOT be called GMSL.
This issue here is that what is posted as a record of GMSL is no longer that. It’s some kind of half-way-house towards finding something else. It’s neither one nor the other but it’s still called GMSL.
Of course if you want to know if coastal plains are going to be submerged in 100 years and the Maldives are going to join their underwater government you’ll be seriously mislead by looking at what is being called GMSL, or trends thereof.
You don’t need a crystal ball to see what is going on here. In 2014 the new IPCC report will be crapping on about the dangers of accelerating sea rise based on this data and other distortions of reality pretending to be science.
Enough!
Another revealing view of what has been sneaked in with the data revision. Looking a plot of second differential we see some significant difference in behaviour around 1998. There is more to this than meets the eye and the other “tidal” adjustments are more subtle than a fix slope you can subtract “if you don’t want it”.
The old data showed what may be an expected response to the globally hot year of 1998, a sudden acceleration in GMSL that has been receding since (Hansen would probably call this rebound).
What the new massaging has done is to even out this feature so as to produce a steady rise in place of the expected step rise and subsequent fall.
This looks dangerously like P. Jones’ attempt to rewrite climate history and rub out the post war cooling with his bucket cooling hypothesis.
Did someone already call this “hide the decline 2” ?
Buzz Belleville says:
May 6, 2011 at 5:32 am
You do understand, fellow posters, that the Colorado page is not just adding 0.3 mm to the current year to show a greater rise in sea levels. It’s adding o.3 mm to all plotted points. It has no effect on the rate of rise.
Maybe I don’t understand, but my question is then why add anything if it has “no effect on the rate of rise.” It’s not the rate, it’s the alarmism. Why not just add 3 mm, or 3 cm (or 3 m), “to all plotted points.” That would still have “no effect on the rate of rise,” but would sure scare a lot of people if they could be convinced that sea level rise was worse than we thought.
I was wondering how this trend in sea-level was correlated with other parameters such as oceanic heat content and variation in length of day from terrestrial conservation of angular momentum.
Just a note on my nomenclature of those plots. Each d/dt is done over an interval of three data points and stored at the mid point date. Effectively a two month average slope. This is repeated to the second differential.
This is then smoothed by a 6 sigma gaussian filter which on this data will have a 6x2x2 month ( two year) corner frequency. No mannian padding anywhere, hence the data stops short of 2011 in the raw data.
P. Solar, They probably don’t even realize. You should write to them.
A G Foster, What’s the academic mainstream rationale for assuming constant GIA?
Buzz Belleville says:
May 6, 2011 at 5:32 am
No, you have not even read what they say then have done. They added 0.3mm per year. EVERY YEAR.
This can be seen in the rate of change I posted.
This does not affect the rate of change of rate of change or second differential of sea level. That gets frigged by the “adjustments” made to the tidal models and anything else they have forgotten to declare and smooths 1998 effects into a steady rise.
We smelt a rat, now we can see it.
Paul Vaughan says:
May 6, 2011 at 9:09 pm
“P. Solar, They probably don’t even realize. You should write to them.”
What bit do you think they don’t realise?
That they have redefined sea level, that they have converted a receding rate of change into a positive one or that they have smoothed out 1998 to give the impression of a steady rate of increase when there is a fall?
I’d be fairly sure with the extended period that they have been working on all this that they are well aware of what they have achieved are busy writing papers to submit to Science and Nature in time to 2014 IPCC.
They probably have the arrogance to think no-one else has the brains to see through it, or think that the odd few that do don’t matter.
What would you suggest I say?
I didn’t find this particularly reassuring:
“Calibration Updated: 2011-05-05
Ideally, one would want to include all of the available tide gauges in the calibration. A number of gauges, however, have a significant lag in reporting of records and are not available for the Jason calibration. On the other hand, some others do not extend backward through most of the T/P mission. We have restricted the ~100 available gauges to a set of 64 near real-time stations that span the majority of both the T/P and Jason missions, and will therefore provide a relatively consistent calibration for both.”
http://sealevel.colorado.edu/content/calibration
Considering the “relatively consistent calibration” and large variations seen in the calibration data, i.e. 1 – 2 mm/year swings:
http://sealevel.colorado.edu/files/current/topex_tgcal.jpg
“adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA),” seems suspect. The method for measuring sea level changes appears quite antiquated;
http://sealevel.colorado.edu/content/tide-gauge-sea-level
and I am curious about the ~36 tide gauges that aren’t “near real-time stations” and aren’t included “in the calibration”.
Perhaps the University of Colorado should spend more time improving their measurement and calibration techniques and less time trying to explain away the failure of sea levels to follow the Catastrophic Anthropogenic Global Warming Narrative…
A G Foster says:
May 6, 2011 at 9:26 am
“But no one here has attacked the adjustment on any scientific basis whatever.”
==============================
Email me at sharkhearted@gmail.com and I will send you a pretty decent attack on this “adjustment” and its “scientific basis.”
Tamino loves to try to overwhelm with about 60% truth and 40% quasi-intellectual spin….such technique attempting to “outsmart” the opponent. (Cue the smoke and mirrors).
The good thing is…there are individuals on here who are on to that game.
Chris
Norfolk, VA, USA
P. Solar says:
They probably have the arrogance to think no-one else has the brains to see through it, or think that the odd few that do don’t matter.
=========================
Bravo and agreed. Keep up the good work.
And yes…the smell of a rat…is getting rather strong.
Chris
Norfolk, VA, USA
Some sharp eyes there. Best documented, documented and archived for history.
Just The Facts says:
May 6, 2011 at 10:02 pm
Perhaps the University of Colorado should spend more time improving their measurement and calibration techniques and less time trying to explain away the failure of sea levels to follow the Catastrophic Anthropogenic Global Warming Narrative…
===================
Extremely well said.
@ur momisugly P Solar: afraid you are seeing a conspiracy where there just isn’t one. It’s all about comparing like with like. Due to GIA the ocean basins are physically getting larger which – just by itself – is reducing apparent sea levels by about 1.2 inch/century (0.3 mm/year). It is entirely consistent with scientific principles that this effect is recognised for what it is and dealt with in the data.
Now the awkward part: there are two ways of handling this. Every 100 years (pro rata for part) CU will know that their sea level data 100 years beforehand needs to be lowered by 1.2 inches (or whatever the precise figure then is) to be consistent with current measurement. They can either (a) adjust and republish all past data by lowering past sea levels retrospectively (wouldn’t that just produce howls of protest) or (b) adjust the current data by reference to a “standard basin size” datum to compensate for the basins becoming larger, which (as you have mentioned) seems to produce a higher current sea level readings – until everybody understands what is really going on.
CU also know that the (modest) rate at which sea levels are rising isn’t the important figure. The absolutely critical figure is any change (acceleration or deceleration) in the rate of rise – the 2nd order differential by time. This isn’t affected at all by the GIA adjustment, so CU obviously considered that the “standard basin” datum was the right way to go.
There isn’t a conspiracy here – only awkward principles and hard sums.