New sea level page from University of Colorado now up

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/

Updated: 2011-05-05

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.

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Jason F

they always correct upwards don’t they

Interesting stuff. Wonder why they only plotted the three first weeks of January?
And this basin stuff is just unbelievable! Someday, they will be adding even more mm rise, for the water that is presently in dams, and should be at sea…
Ecotretas

Braddles

The trend since early 2002, when the Jason satellites came into play, is only 2.3 mm/yr. Without all the convenient adjustments it is lower still.

Ray Boorman

Even though the actual sea level is what they purport to measure, they decide to add a small positive adjustment every year for the fact that some parts of the land are rising due to rebounding from the last ice age. Measurements are measurements where I come from, & if my local tide guage showed a rise of 2.7mm a year because the land is rising by 0.3mm, than that must be the true reading. Do they also adjust for the fact that any rising land areas are also increasing the sea-level rise in those areas which are not rising? I can’t see how this adjustement is anything other than an artifice to satisfy the CAGW believers.

Warren

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.

Sorry, they lost me with adding then subtracting, then saying it didn’t matter and I could use the previous reading without the addition?
And still researching La Nina?
My head hurts.

Hunter

The GIA seems irrelevant to me. As I understand it, sea level is measured in reference to land. If they were reporting on sea volume, then I could see making a case for that. At least they added the caveat that we can ignore the GIA if we want to.

So we are no longer measuring actual sea level but adjusted values bases on assumptions. The actual levels are what we want not ( well the sea is actually rising more than actually measured because of xyz so its worse than we thought).
As far as La Nina causing a drop in sea level, surely this is spurious. An upwelling of cold water is not cooling the ocean overall. In fact because the surface is colder the ocean would be losing less energy overall in those cooler areas compared to energy absorbed from the sun. There would be a drop in sea level locally but this would be reflected by a rise elsewhere.

Mac the Knife

“we have made many improvements to our data (new orbits, new tide model, new corrections)….”
Models are data now? Really?
How do you ‘improve’ data? Data is a recorded physical measurement of some characteristic. Any adjustment to the data, without retaining and disclosing the original data, invalidates it.
“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. ”
Aren’t these same global ocean basins also subject to siltation inflows from river deltas, wind blown dust from desert regions , volcanic eruptions and lava flows directly into the oceans, and even in-falling debris from space? Are these also factored into their ‘global ocean basin models’? All of these natural effects contribute to naturally rising sea levels by making the basins slightly smaller. They should be subtracted from the overall trend.

Ray Boorman

And do they also play off against each other the movements of the various tectonic plates? Eg India is pushing into Asia, which enlarges the Indian Ocean, but Africa is tearing itself apart, which diminishes the same ocean. They might also want to take into account the rise & fall of various plates as a result of earthquakes. The more you think about it, the more complicated a simple idea like sea level becomes.

Brian H

Aha! So the deepening of the basins is creating a 0.3mm increase? Or zero apparent increase is now actually 0.3mm/yr?
Whatta crock.

LabMunkey

Huh, the new data’s knocked the average rate-rise down from 3.4 to 3.1 mm/year i see.
I wish i could still find their data of the tidal gauge and satellitte data together. they used to have it all on one graph, it ws a great resource- but i haven’t been able to find it for ages.

Mike Bromley the Kurd

Isotasy to the rescue (of rising sea level)! It is now rising the thickness of an ink line faster than before because of….ice that already melted. A new tide model? Does that change how the Bay of Fundy’s tides work?
Regardless, at 31 mm/decade, it’s not rising like Some WTWT catastrophists would have us believe…so why do they keep screaming that it is?

chris1958

Methinks putting in the GIA is a little naughty if the principal metric of practical significance is the actual rise in sea level compared to levels on land. Of course, if we’re interested in oceanic volume, then that’s another story.

Andrew30

“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), ”
How was this calculated given the extent of the glaciations, the total land mass and the area and volume of the oceans?
How was this 0.3 mm/year able to calculated and added to the overall calculation without affecting the prior uncertainty +/- 0.4 mm/year?
It does not seem possible to calculate the affect of isostatic rebound on the global average sea level to 0.3 mm/year with +/- 0.00 mm/year uncertainty.
I don’t buy it. It looks like they added a constant so that the rate did not change.
3.1 mm/year +/- 0.4 mm/year.
“Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.”
It is not a ‘correction’ it is a Constant Value added to have the data match the previously specified trend line.
Does anyone believe that by co-incidence adding the ‘GIA correction’ results in Exactly the same 3.1 mm/year +/- 0.4 mm/year that we saw in 2010_rel4?
I don’t buy it, it smells bad.

Martin Brumby

“the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land”
OK, how does that work? (Honest question, not my usual sarcasm).
“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”
So La Nina has been hard at it, unsuspected, since 2008?
(Sorry, sarcasm back on again…….must try harder…….)

Mike McMillan

So down from 3.2mm/yr to 2.9 if you don’t count their latest ‘adjustment.’ With any luck we may stay below even the adjusted line for a few decades if the apparent cycle in Tokyoboy’s Japan tide chart is real and worldwide.

Dave A

From http://sealevel.jpl.nasa.gov/technology/
From its vantage point 1336 kilometers (830 miles) above the Earth, the US/European Jason-1 and OSTM/Jason-2 ocean altimeter satellites measure the height of the ocean surface directly underneath the satellite with an accuracy of 4-5 centimeters (better than 2 inches).
n.b. centimetres not millimetres 🙂
throw in an unsubstantiated positive 5mm fiddle factor over the period of the graph. Cross calibrate with previous satellite to maintain the positive trend (c.f Mann, trees and real life) and admit that the surface of the earth moves as in the case of Japan’s 8 foot coastline shift earlier this year
and then be amazed that your latest measurements show a decrease you cannot explain
A 5 cm increase over 17 years measured by 3 different instruments accurate to 5cm from a height of 830 miles
I’m scared we are all going to drown :-S
:-))
Dave

Jantar

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),
Translation: “We believe that the recent fall in sea level will decrease the apparent rate of rise by 0.3 mm/year, so we’ve adjusted this out.”

Bug shmug.
So, if we don’t like the GIA correction, just remove it.
How about they don’t include the GIA correction and tell people if
they want to increase the rate of GMSL…
wait, oh yeah, that would be double dippin…. my bad.
/sarc

They’ve dropped Envisat from the record. Without explanation.

Here’s their data which I saved from the old Colorado website:
http://members.westnet.com.au/jonas1/ColoradoUniArchivedData.txt
I have very quickly graphed the old and new data, and I have not checked it carefully!!!
Graph of old data:
http://members.westnet.com.au/jonas1/ColoradoUniOldData.jpg
Graph of new data:
http://members.westnet.com.au/jonas1/ColoradoUniNewData.jpg
Graph of the differences:
http://members.westnet.com.au/jonas1/ColoradoUniDiff.jpg
Interesting.
By my calcs, the overall trend in the new data is less than in the old data, even though they say they have added 0.3mm p.a.
Also, there is a clear downturn in the data in recent years. They say “La Ninas”, I say PDO cooling phase.
In haste …..

TimC

What’s all the fuss? If the ocean basins are getting larger due to GIA then there should be some adjustment so that the decadal/centennial data is self-consistent. And it’s not the fact that sea levels are rising that’s important, but rather the 2nd order differential – any acceleration or deceleration in the rate of rise – that’s crucial.
If it’s feasible to reverse out thermal expansion effects due to ENSO, PDO, AMO et al that’s even better – this will eventually give true self-consistent altimetry data on decadal/centennial timeframes so we can then see whether there is any substance at all in this CAGW scare.
The only really important issue is that all adjustments to the data are properly documented.

Since I had last archived raw data (in 2010.6057) several new cycles appear in this data, that were not available before:
2004.1173
2006.8864
2008.6782
2008.7325
2008.814
2009.0311
Ecotretas

rbateman

vaporware.

Don Keiller

So the rate over the last 19 years is 3.1mm/year. That comes out at 310mm/century.
In old money that is 12.2 inches.
OVER A FOOT! IT’S WORSE THAN WE THOUGHT!

Jimbo

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.
Yeah, right. Do they make adjustments for water extraction?

Jimbo

I forgot to bold
“(new orbits, new tide model, new corrections) “

I notice that much of the Topex trace is below the line – then much of Jason 1 is above the line ?
Has anybody double checked their 2002 join Topex to Jason 1 ?

Edim

This was to be expected. Hide everything that dilutes the message. Under the carpet!
Long term it cannot work. The pile under the carpet is getting bigger and bigger…

roger samson

I just hate it when people tinker with long term data. This looks like hide the decline part 2.

John Peter

So to get to the IPCC predictions of sea level rise to 2100 we need some acceleration in the yearly rise. I see no such acceleration. In fact there is a recent deceleration. The next few years will be interesting.

I’ve made a small essay regarding the rate of rise:
http://ecotretas.blogspot.com/2011/05/rate-of-sea-level-rise-going-down.html
It’s going down and FAST! In my opinion, the data was stopped because in cycle 2010.7415 the trend was 2.956158611 mm/year, just enough to round it to 3.0
They have had these months to re-engineer the values so they are at least still bigger than 3.0 mm/year!
Ecotretas

sHx

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.
Hocus pocus!

Mike Hebb

Why don’t they give sea level relative to shorelines where it counts to us inhabitants? Maybe it’s that some are rising and some are lowering due to isostacy and drift and would mean an inconsistent mishmash of positive and negative numbers to average?

Roger

Is anyone positively, absolutely, no doubt about it, convinced they can even measure a 3 inch rise in sea level, over any given amount of time, for the entire world?

Peter

I imagine Mike Mann did some decentered PCA to calculate that adjustment for them… When the data is not behaving, they just call in a cleaner from AGW team headquarters.

Buzz Belleville

A 100% transparent adjustment based on legitimate observations and folks here are still complaining. It’s not like the Colorado folks are trying to slip one past you.

BarryW

So La Ninia’s cause a drop but El Ninio’s don’t contribute to the rise?

4 eyes

If the mid 2011 number comes in the same as the last bit of 2010 then I’d say that trying to fit a straight line to the data is folly. Then the plot would have more of the characteristics of a sine wave with a period of about 30 years rather than a straight line

stephen richards

Why do they insist on adjusting empirical data. Sea level is sea level. If I put water into my swimming pool and measure that level on a regular basis, which I do, I don’t make adjustments for the movement of the walls due to weight of water or the descent of the whole pool relative to the surrounding soil. The level is what it is. The data is what it is. LEAVE THE BLàèDY DATA ALONE! It’s cheating. Nothing but cheating. What are the objectives behind sea level measurement? Is it to calculate the point at which we need to be build our houses further in land or on stilts? Is it to allow us to change the profiles of our ports to keep them open? or Is it to prove that the glaciers are melting and we need more funds.

Latitude

So they are adding a constant to it…
..and it’s still going down

stephen richards

Buzz Belleville says:
May 6, 2011 at 4:18 am
A 100% transparent adjustment based on legitimate observations and folks here are still complaining. It’s not like the Colorado folks are trying to slip one past you.
Just because it’s “transparent” doesn’t make it right!! Puuleeze!!

@Buzz Belleville
It depends on the point of this measurement. Typically, people think about sea level rise being how much coastline on average is being reclaimed by the sea because that is what is most important to people on the coast. If that’s what this is supposed to be measuring, adjusting for changes to the volume of ocean space is not helpful.
I have nothing against measuring volume. That would be interesting to track. I’m not sure we have the technology to really do it with any accuracy though.

P. Solar

More hide the decline pseudo-science.
If this is supposed to be a record of sea level it should be showing sea level. It is not supposed to be a record of ocean volume. GIA is a fraud. This is no longer a measure of sea level but some other metric.
People, governments etc. are concerned about sea level as it relates to land. That is what all the alarmism about sinking atolls and flooded coastal plains is based on.
If we want to infer sea volume from sea level *then* there may be a need to apply some adjustment. At that point we need to look at where these adjustments come from. Let me guess… simplistic computer models.

Buzz Belleville

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.
And the adjustment for GIA is based on peer-reviewed scientific literature, not some nefarious whim.

Bill Illis

Regarding the glacial adjustment, the glaciers were primarily on the land. The extra weight pushed down the land and the primarily non-glaciated ocean bottom would have increased slightly or bulged up in compensation.
Now that the glaciers are gone, the land is rising again and the ocean bottom is sinking back to its non-glacier position. There is also the weight of the extra water (which was formerly on land in glaciers) which is now in the ocean which is also pushing down on the ocean bottom.
The overall average depth of the oceans is sinking enough to lower sea level by 0.3 mms per year.
Since sea level is actually measured at increasing 2.7 mms/year, the actual volume change of the water in the oceans must be 3.0 mms/year.
Note that the sea level is actually only increasing by 2.7 mms/year.
(So I think it really shouldn’t count here. If you are going out 100 years and trying to say New York will be flooded by the ocean, you shouldn’t add in the Glacial Isostatic Adjustment because the sea level will not actually increase as a result of this adjustment).

“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.”
So, La Nina is affecting the heat content of the Pacific.
I’ve been told that La Nina only causes redistribution of heat. Cold water coming up from the deep and warm water moving away to the west. Not a heat loss in the Pacific causing thermal contraction.
I say look to the PDO!

Green Sand

“NOBODY expects the Glacial Isostatic Adjustment!
Our chief weapon is surprise…surprise and fear…fear and surprise….
Our two weapons are fear and surprise…and ruthless efficiency….
Our three weapons are fear, surprise, and ruthless efficiency…and an almost fanatical devotion to the Pope….
Our four…no… Amongst our weapons…. Amongst our weaponry…are such elements as fear, surprise…. I’ll come in again.”
With respect to Monty Python

TimC

@ steven richards: it’s not a matter of right or wrong but of comparing like with like. The ocean basins are physically getting larger which – all by itself – is reducing sea levels by about 1.2 inch/century. This is before you can get an accurate picture of the important stuff such as the effect of thermal expansion and the rate land-based ice is melting.
Surely you are not suggesting this should just be ignored – good science means that it has to be recognised for what it is. To compare like with like I suggest it’s better that the figures are adjusted, otherwise we will all have to remember to make manual adjustments every time we look at the data.
I also hope it will later be possible to make accurate adjustments for the effects of thermal expansion, so we can finally get an accurate handle on whether there is any change in the rate at which land-based ice is melting (ie. whether global surface temperatures have truly risen or not).

Pamela Gray

We have gone completely bonkers. Our researchers have succumbed to the idea that every natural phenomenon must have human causes. They have even added sacrificial austerity and demands for tithe to the backs of peasants.
Turn the money changing table on its head and kick the tax man out of the courtyard. Else we will be forced to join the masses at this temple of research. Eisenhower had it right all along.