The pause, and sea levels.

[Sorcery]

Think I have found a possible explanation of the difference between satellite data and tide gauge data from WUWT that has been bothering me,: https://wattsupwiththat.com/2016/05/28/ ... eleration/

Mark - Helsinki May 28, 2016 at 10:01 am
This is exactly why they focus on the bogus satellite gained average mean crap.

PA May 28, 2016 at 4:59 pm
Well, it isn’t bogus… But you have to adjust it a bit.

1. The GIA (global isostatic adjustment was added in 2011 because the sea level wasn’t rising fast enough. The sea floor is sinking an estimated 0.3+ mm per year so they arbitrarily add 0.3 mm/Y. There is absolutely no sane reason to add GIA since this changes a measured sea level measurement into an estimated change in ocean depth.

2. They mask the land area. Now if the sea is sinking 0.3+ mm/y the land is rising 0.7+ per year. Lets call this LIA (Land Isostatic Adjustment). The masking artificially inflates the sea level 0.7+ mm/Y.

GMSL trend ~ 3.3 mm/Y – 0.3+ (GIA) – 0.7+ (LIA) = 2.2 to 2.3 mm/Y.

So the satellites are measuring the same sea level rise as everyone else. They are just reporting it badly.

Chris Schoneveld May 29, 2016 at 10:37 pm
PA, GIA is NOT global. GIA stands for Glacial Isostatic Adjustment

The poster PA is a regular there and at Climate etc. He is not a climate scientist as far as I am aware however he doesn't make stuff up also as far I am aware. If true it does seem insane and incredible that it's adding 0.3mm a year because the sea bed is sinking. What matters surely (threat-wise) is surface sea level relative to land.

[escalader]

Think I have found a possible explanation of the difference between satellite data and tide gauge data from WUWT that has been bothering me,: https://wattsupwiththat.com/2016/05/28/ ... eleration/
...
So the satellites are measuring the same sea level rise as everyone else. They are just reporting it badly.

Chris Schoneveld May 29, 2016 at 10:37 pm
PA, GIA is NOT global. GIA stands for Glacial Isostatic Adjustment

The poster PA is a regular there and at Climate etc. He is not a climate scientist as far as I am aware however he doesn't make stuff up also as far I am aware. If true it does seem insane and incredible that it's adding 0.3mm a year because the sea bed is sinking. What matters surely (threat-wise) is surface sea level relative to land.

Sorcery

It is a LOT more complicated than that!

Did you follow the NASA link I posted earlier? It is much more reliable than either of the web sites you keep linking to that are well known sources of misinformation. If you are really interested there is this peer reviewed paper, but it was too technical for me!

Regards

esc

[escalader]

Forgot to post link!
https://www.researchgate.net/publicatio ... c_benefits

Also this paper is a bit more readable

http://academics.eckerd.edu/instructor/ ... ustain.pdf

[Sorcery]

Escalader,

Thanks for the links, I do appreciate that the science is very complicated. The engineering that goes into satellites is phenomenal. My problem is simply this: The opening post linked to this http://climate.nasa.gov/vital-signs/sea-level/

There are 2 graphs there that purport to show the same thing namely sea levels, they even overlap for 7 years. The tidal gauge data shows an increase of 1.54mm per year. The satellite data shows 3.4mm per year. One of those is wrong or measuring something different. The tidal gauge data stops at 2000 which is disappointing. Neither shows much acceleration visually though it might be possible to find a small factor for it mathematically. Pretty soon we will might see a graph of them grafted together and then someone will say look : acceleration.

I have been searching without success to find out the more recent global tide gauge data or an explanation of why the two graphs are different. It seems remiss to offer both graphs without an explanation of the differences especially since sea level rise is the number one risk from AGW. One possible explanation might be that the tide gauge data graphed has not been adjusted for local GIA though that would be remiss too.

I do not doubt Judith Curry's integrity. The comments on her site are all over the place though with just about every possible misunderstanding. Professors Pielke senior and junior, retired Professor Vaughan Pratt all post and commentate there and are good.

[escalader]

I have been searching without success to find out the more recent global tide gauge data

Do you mean like this:

https://www1.ncdc.noaa.gov/pub/data/ush ... al2010.pdf

[robbelg]

I have been searching without success to find out the more recent global tide gauge data

Do you mean like this:

https://www1.ncdc.noaa.gov/pub/data/ush ... al2010.pdf

That's about US surface temperature not sea level!

[escalader]

escalader wrote:


I have been searching without success to find out the more recent global tide gauge data


Do you mean like this:

https://www1.ncdc.noaa.gov/pub/data/ush ... al2010.pdf

That's about US surface temperature not sea level!

Sorry chaps!

Try this.

https://www.epa.gov/climate-indicators/ ... -sea-level

[Sorcery]

escalader.
Excellent find. So tide gauge data roughly matches satellite data in your link.
A 3 inch rise in sea levels over the satellite period again from your link roughly matches the rise in the first nasa graph satellite record.
A 9 inch rise in sea levels over 135 years is still only 1.69mm/year however.

Since your link shows the tide gauge data matches roughly the satellite record I concede defeat and concede that those up to date graphs show an accelerating rise. Well done you changed my mind!

Regards

[Injunear]

Again, a meaningless collection of words. I'm saying that most of the accumulated heat resulting from radiative forcing (the difference between incoming and outgoing energy fluxes at the top of the atmosphere) goes into the oceans.

I agree that the second sentence is a meaningless collection of words. It's nice that we agree on something.

If you have time maybe you can explain what you mean when you say "datum zero forcing state"?

Whatever state the planet is in (with respect to its energy content) at some point in the past when there was no radiative forcing. Alternatively, the equilibrium state of the system in the absence of radiative forcing.

According to your definition above, at what point, since the ignition of the sun and existence of planet earth, has there not been radiative forcing?

After that maybe we can try to extract meaning from your phrase "Most of the accumulated heat ... goes into the oceans". You seem to be saying that heat is accumulated (somewhere) and then (by some means) ends up accumulated somewhere else. Since heat is only internal energy there is nothing contentious in saying that heat is accumulated if by this you mean that energy is stored in matter. Obviously also it is possible for energy to be stored in water molecules (at least temporarily). What is not clear is whether you are saying that energy is stored in water (obvious) or that energy is stored first in one place and then preferentially is stored somewhere else (not so obvious).

[XFool]

After that maybe we can try to extract meaning from your phrase "Most of the accumulated heat ... goes into the oceans". You seem to be saying that heat is accumulated (somewhere) and then (by some means) ends up accumulated somewhere else. Since heat is only internal energy there is nothing contentious in saying that heat is accumulated if by this you mean that energy is stored in matter. Obviously also it is possible for energy to be stored in water molecules (at least temporarily). What is not clear is whether you are saying that energy is stored in water (obvious) or that energy is stored first in one place and then preferentially is stored somewhere else (not so obvious).

This too is going to take a very long time.

[Sorcery]

Well having enjoyed a pleasant night's sleep while dreaming about drowning from rising seas the demon of doubt came to my aid. Not really

https://www.epa.gov/climate-indicators/ ... -sea-level says

This graph shows cumulative changes in sea level for the world’s oceans since 1880, based on a combination of long-term tide gauge measurements and recent satellite measurements. This figure shows average absolute sea level change, which refers to the height of the ocean surface, regardless of whether nearby land is rising or falling. Satellite data are based solely on measured sea level, while the long-term tide gauge data include a small correction factor because the size and shape of the oceans are changing slowly over time. (On average, the ocean floor has been gradually sinking since the last Ice Age peak, 20,000 years ago.) The shaded band shows the likely range of values, based on the number of measurements collected and the precision of the methods used.

Why does shape of oceans matter to sea level rise? Obviously they will affect sea levels up if sea surface area is smaller and sea levels down if surface area is larger. But what matters is sea level rise, why should it need adjusting for that?
What does ocean floor depth matter to sea level rise? By roughly the same logic it ought not to.
Why are tide gauges being adjusted for sea volume changes?
I am very happy that they thought the need to explain that they did it but the lack of a why? leads to dark places that I dare not go. Like that's nuts.

This is the same problem that PA was addressing in my reference to him in comments here on the 15th, so a credit to him, he/she was not making it up.

[Nimrod103]

https://www.epa.gov/climate-indicators/ ... -sea-level says

This graph shows cumulative changes in sea level for the world’s oceans since 1880, based on a combination of long-term tide gauge measurements and recent satellite measurements. This figure shows average absolute sea level change, which refers to the height of the ocean surface, regardless of whether nearby land is rising or falling. Satellite data are based solely on measured sea level, while the long-term tide gauge data include a small correction factor because the size and shape of the oceans are changing slowly over time. (On average, the ocean floor has been gradually sinking since the last Ice Age peak, 20,000 years ago.) The shaded band shows the likely range of values, based on the number of measurements collected and the precision of the methods used.

Why does shape of oceans matter to sea level rise? Obviously they will affect sea levels up if sea surface area is smaller and sea levels down if surface area is larger. But what matters is sea level rise, why should it need adjusting for that?
What does ocean floor depth matter to sea level rise? By roughly the same logic it ought not to.
Why are tide gauges being adjusted for sea volume changes?
I am very happy that they thought the need to explain that they did it but the lack of a why? leads to dark places that I dare not go. Like that's nuts.

This is the same problem that PA was addressing in my reference to him in comments here on the 15th, so a credit to him, he/she was not making it up.

I think there are some fudge factors being used here which are not explained, which leads me to think they may be invented. Tide gauge data is obviously subject to changes in the height of the land relative to the sea, and is therefore rather unreliable. Most of the coasts of places closely studied (like the eastern USA seaboard and the Mississippi Delta) are sinking due to sediment loading the crust, normal compaction and aquifer water abstraction.
Only satellite data may be reliable, provided adequate coverage and unbiased averaging. But the satellite data has been 'adjusted' upwards (see the graph labelled 'Sea Level Changes Based on Satellite Data' in http://www.justfacts.com/globalwarming.asp#_ftn248). It is a little unclear, but the upward adjustment seems to have been done because the adjusters have assumed that post glacial seabeds are sinking, so the volume of sea water is increasing and so the actual curve is adjusted upwards to show what the sea level rise would have been, if the seabed had stayed the same. I stand to be corrected, but I know of no evidence or reason why post glacial seabeds should be deeper, so I would prefer the 'actual' data. This shows that the rate of increase in sea level has been decreasing the last 10 years, and might even be levelling off.

[Sorcery]

... I stand to be corrected, but I know of no evidence or reason why post glacial seabeds should be deeper, so I would prefer the 'actual' data. This shows that the rate of increase in sea level has been decreasing the last 10 years, and might even be levelling off.

I can see one reason that the sea beds might be lower since according to this
https://ourchangingclimate.wordpress.co ... se-graphs/

sea levels are now 120m higher than at the last glacial maximum. That's an extra 12 bars of pressure on the sea bed. Another similar idea might be that for seabeds it's an the inverse effect of isostatic rebound on land, seabeds at the glacial maximum are likely to be pushed up because land is pushed down when loaded with km of ice, which might force sea bed rise and then reverse when the ice disappears. Speculation of course but horizontal effects of land displacement across to seabeds seems possible imho.

However let's take the poster "children" for AGW a flooded London or New York, there it's sea level rise relative to land that matters for the disaster to happen. I am very happy if the seabed is sinking , less likelihood of sea level rise relative to land.
I also would happily take an unadjusted average tide gauge data as the prime measurement for danger, (unadjusted except for the tides). Sea bed warping is unimportant to that except as far as it changes sea levels relative to land. I fear that real measurements may be being gradually usurped by adjustments for no good reason.

[Injunear]

If you have time maybe you can explain what you mean when you say "datum zero forcing state"?


Whatever state the planet is in (with respect to its energy content) at some point in the past when there was no radiative forcing. Alternatively, the equilibrium state of the system in the absence of radiative forcing.

Please can you enlighten us all as to when "at some point in the past" there was no radiative forcing?