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.
“the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land”
So the Earth is expanding according to that statement, funny how there is a equal return of rock to the depths of the ocean caused by glacial erosion, which is not mentioned, which would cancel that out.
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.
Buzz, per their website, the GIA adjustment was “-0.3 mm/yr. That’s per year.
The most recent ‘pre-adjusted’ data point for 2010.7415 was 28.119 mm.
This ‘post-adjusted’ data point for 2010.7415 is now 36.996 mm.
So you’re correct that they didn’t just add 0.3 mm to the current year, they added 8.877 mm to the most recent common data point
It does affect the rate of rise!
Buzz Belleville says:
May 6, 2011 at 4:18 am
………. Transparency is neither a guarantor of correctness nor honesty, but often screens out the opposite of both.
Hey Buzz.
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.
What’s good for the goose is good for the gander. It seems to me according to the logic applied to the “adjustment”, when the process reverses (as it inevitably someday will) and sea levels begin to decline the “coolists” will be able to chirp, “It’s even worse than we thought! We must SUBTRACT 0.3 mm per year to account for ocean basins rising and land masses falling! Shut down the windmills and start burning something – quickly!”
Response to bushy says:
May 6, 2011 at 12:03 am
Surely cold water welling up from the depths would be warming and expanding when it got to the surface.
Post Glacial Rebound (PGR) is highly variable. The continental crust in areas that were glaciated has been rising for the last 15,000 to 18,000 years. However, the continental crust in the fore-glacial bulge areas has been subsiding.
Did they actually calculate the net 0.3mm/yr GIA? Or is than an assumption?
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..”
Buzz, I don’t believe you are correct. The website reads “One important change in these releases is that we are now adding a correction of 0.3 mm/year…”
This means they are adding 0.3 mm every year. Over a period of 10 years, they have added 3 mm. Over 100 years, they have added 30 mm. This does affect the rate of rise. There is nothing scientific about the adjustment. The only solution is to remove the adjustment as they suggest. My question is at what year did this new adjustment begin?
Buzz Belleville said at 5:32 am
You do understand, ….. It’s adding o.3 mm to all plotted points. It has no effect on the rate of rise.
What? Did you miss the part where he said:
… so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases
AND “if” the 0.3mm is added to ALL data points – – why even bring it up? or add it? or why not 0.9mm? or -0.5mm? or 6.7mm?
In the article, http://wattsupwiththat.com/2011/04/17/doing-it-yourself-the-latest-global-sea-level-data-from-jason-shows-a-sharp-downtick-and-downtrend/, RomanM had plotted a data point from the Jason-2 data set, showing the most recent measurement was at ~12mm from the 0 line. That data point does not show up on the UofColorado site.
Does anyone know what happened to that data point? Sure it was just one data point, and perhaps it was a spurious reading of some sort, but I’m curious what happened to it.
Ok. Only 3 measurements in 2011 so far. Lets look at measurement #3 over the last few years.
2006.0720 25.011
2007.0765 31.094
2008.0810 34.438
2009.0583 39.251
2010.0628 31.337
2011.0673 30.809
5.7mm over 5 years = 1.14mm per year
Acck. We are all gonna drown!
This is the funniest thing ever. La nina causes the oceans to not rise as much….Its like they look at data that does not follow what the believe/know about so they invent some fairy tale to explain it.
I can see it now, they are all gathered in the lounge and are discussing this. One of the interns pipes up, what if its la nina?
It gets put down. Makes no sense, since la nina has never been shown to do this to sea levels in the past so directly, but why not? Its an explanation….which “is under further research”. Which means that the idea from the peanut gallery is going to be researched with the Government’s money. Of course all tax payer monies belong to the Gov. and are not ours to use….as goes the belief.
And for adjustments, if you are claiming to show the actual data, you DO NOT EVER adjust the data without a good reason to do so.
No case is made about how this changes or skews the data…so in the end the adjustment is spurious, un-needed and just simply put retarded.
Looks like the peanut gallery is alive and well at the University of Colorado with that same peanut gallery running the show.
Buzz says:
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.
____
Look at what they say themselves again:
“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.”
Who are we to believe? You say adding an annual adjustment every year does not affect the rate of rise, but they say it does. This may have only a one time effect on the slope of the graph, thus not showing an ever increasing acceleration trend, but it does have a constant, continuous, cumulative effect on the slope from what it actually should be (if we are actually measuring sea level). It’s “a trick to hide the decline” in plain sight all over again. “We explained it in the literature so it’s okay to produce a bogus graph” is the party line I believe.
Lots of misplaced skepticism around here. I see only 2 or 3 posters who understand the problems involved. There is no such thing as sea level per se–the sea isn’t level. Sea level at one Hawaiian island rises at a different rate from another–the younger islands sink faster as they settle down from their more recently added magma. Wind and the Coriolis effect can easily raise sea level a foot. The two coasts off Panama have different heights. The two sides of the causeway on the Great Salt Lake have different heights due to different salinity levels.
And the planet constantly changes shape; they do well to quantify the effect of GIA on sea level rise–it’s very hard to measure, or calculate. And the paradox of sea level rise versus falling LOD remains. Munk wanted to use long range sonar to measure deep sea density (salinity/T) globally, but it was determined this would hurt lots of cetacean ears, so data are still sparse.
On the other hand, population density increases due to natural growth about a thousand times as fast as due to current sea level rise, and if all the ice on the planet melted, it would still make less difference than current population growth rates. In the unlikely event that Greenland’s ice melted, natural population growth remains a far more serious problem. But we can handle it. –AGF
Also seems that the barometer adjustment is now obligatory.
http://sealevel.colorado.edu/content/new-web-site-new-sea-level-release
The inverted barometer correction (optional in previous releases) is now always applied for each mission.
The GIA model was turned upside down when new GPS data revealed that the ice/bedrock interface of the center of Greenland was sinking rather than rebounding.
This resulted in a 50% reduction from the previous estimation of the ice loss from Greenland. This means that the mass component of sea level rise would also need to be adjusted downward at a time when ARGO is revealing very little thermal expansion.
http://thegwpf.org/the-observatory/1438-ice-sheet-loss-cut-in-half.html
Since the previous estimates were based on gravity changes in time detected from the Grace satellite they must have come up with a crustal explanation due to plate tectonics to explain the gravity changes.
I wouldnt be suprised if they made the correction backwards as the new GIA means less mass component contribution. Gravity is very tricky.
Never mind, we found the adjustment knob, the NEW and IMPROVED adjustment hereinafter known as the GAIA adjustment will correct for all previously measured data points such that the current remains forever WORSE THAN WE THOUGHT!
A little GAIA in your data will correct the info. Trust us for we know the truth.
Buzz Belleville says:
Either Buzz is blinded by devotion or does not understand the relationship between rate and position. 0.3 mm/year is a rate of change, NOT an offset as he asserts. Ergo, at some unspecified point on the horizontal axis they decided was the zero of the GIA. Since it is “mm per year“, it is a slope adjustment (i.e., cumulative), not an offset adjustment.
Thus, the sea level point on the graph is 1mm (0.9mm, technically) higher in 2007 than 2004, and the 2011 level is 3mm higher than 2001 purely due to GIA and no other factors. Thus, the actual sea level rise since 1998 is 3.9mm less than graphed, i.e. less than 30mm or 3cm or less than 1.2 inches. For the duration of the graph, it totals 5.1mm in adjustment. Again, who knows what point in time they decided was zero GIA…
(There are some folk who just don’t deserve to live in CO. I’m proud to have RPS & Drs. Gray & Klotzbach, however.)
“the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land”
Questions for the University of Colorado
– Why are we no longer measuring actual sea level in the new graph, and what is the point of making a positive adjustment to highlight what the level would have been otherwise ? We only really want to know when our toes will get wet in the morning when we get out of bed !
– If the mantle movement is a negative feedback to observed sea level rise then why is this not highlighted by the IPCC in their sea level prediction forcasts ? After all, this is a good news story !
And finally
– What was your measured isostatic rate of increase in 1980 ?
– What is your predicted isostatic rate of increase in 2100 ?
I’m guessing that the rate remains very constant, and if this is the case then how is it relevant to AGW ?
The rebound adjustment is ridiculous. It is the relatvie change in height of the ocean with respect to land that is important. If oceans were increasing at 50 meters a year, as long as “land” height was aslo increasing at 50 meters per year, you would see no effect at the beach because the net difference is ZERO. In fact, I would maintain that tide gauges are the “Best” measurement for determining relative sea level rise. Expressed another way, if ocean levels are falling at 5mm per year but the land happens to be falling at 1 meter per year, I’d say you should start taking actions to mitigate flooding but the experts based on their logic would be saying just the opposite.
David Middleton says:
May 6, 2011 at 7:00 am
Post Glacial Rebound (PGR) is highly variable. The continental crust in areas that were glaciated has been rising for the last 15,000 to 18,000 years. However, the continental crust in the fore-glacial bulge areas has been subsiding.
Did they actually calculate the net 0.3mm/yr GIA? Or is than an assumption?
My money is on “make a simple computer model and adjust the parameters until you get the desired result”.
but I’m just old and cynical. I suggest you look at the link to the paper they give in release notes :
http://sealevel.colorado.edu/content/release-notes
Abstract:
… the second may be estimated on the basis of mass balance measurements on existing ice-fields, and the latter on the basis of modern GRACE-based time dependent gravity field measurements, the inputs to the globally averaged rate of sea level rise may be directly constrained.
But hang on, interpreting GRACE gravity data for ice sheets requires a model of mantle rebound.
models upon models , wheels within wheels, and they claim +/-0.4 on 3.1 , that’s +/-13%. That probably does not even cover the uncertainly in the satellite data never mind the grossly simplistic, globally averaged rebound models.
A G Foster says:
May 6, 2011 at 7:44 am
Are you Tamino?
@ur momisugly JonhH – no, the earth isn’t expanding: magma is just slowly flowing away from the ocean basins (which are therefore dropping) into the formerly glaciated land areas no longer bearing the weight of all that ice, which are rising. It’s rather like squeezing a toothpaste tube with the cap on – the total volume is unchanged.
@ur momisugly Old One: I believe it’s a uniform adjustment of ~0.3mm for every year since the datum year 1980 – so the adjustment is ~0.3 * 30 = ~9mm total today. Yes this does uniformly affect the rate of sea level rise but only at the first differential by time: the all-important second differential (changes in the rate of rise) is not affected.
CU must show the data without a hypothesized GIA correction.
Make another graph with the GIA included.
Then TRY to explain the difference. Everyday to everybody.
When CU gets tired of explaining and defending a GIA that is not hidden from view, they’ll decide to deep six it.
This is the Urban Heat Island effect come to sea-level data.
I think it is interesting that University of Colorado is taking on the glacial isostatic adjustment. This is real. As we know releative sea level at high latitudes appears to be declining as the coast rapidly rebounds.
http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml
Sea levels at lower latitudes appear to be rising faster especially when measured adjacent to subsiding coast lines. Relative SLR measured adjacent to the stable Australia craton have only shown about 1.2 mm/year. My bet is that they are applying this correction the wrong direction. The test would be to take a station with GPS data adjacent to it and see how it fits. In other words if an Alaska station shows -8mm/year releative sea level decline then the GPS station on the coast adjacent better show 8 mm/yr +3.1 mm/yr. This should be easy to check out.