Dim Sun Anyone?

[tomclarke]

What a lot of interesting points you all raise!

First O/T point:

The fact apparently nothing would falsify AGW for you tends to prove my point global warming is more of a pseudo-religious belief than a scientific proposition. You also don't seem to see any problem with believing AGW is simultaneously too uncertain to be falsifiable in any reasonable time frame and 90% certain. Ah, the marvel of human rationalizations.

You impugn my integrity. I admit to being unclear about this when you asked, because I would look at the whole temperature record, the known non-CO2 variations, etc. And to make a good answer i need to look MYSELF at all the scientific evidence. A full-time job.

My current understanding (since I prefer to trust Hansen/GISS rather than random blogs, in absence of other evidence) is this:

(1) ENSO/PDO - currently cold. Can't predict certainly how effect of this will change since La Nina/El Nino etc events chaotic and cold/hot depends on which happens but current anomaly is -0.7C and very likely to change back to more + in next 12 months. Compare this with 0.2C/decade average increase from CO2.

(3) solar irradiance - currently at 50 year low. Not likely to get lower than at present. Whether it will increase again or stay low depends on whether sunspot cycle restarts as normal. Just suppose it does not, then effect is -0.2W/m^2 forcing (difference between max & min in solar cycle). This is equivalent to 0.15C.


So the current negative temp is result of -0.075C (solar) and -0.7C La Nina/El Nino events which themselves are influenced by ENSO/PDO. (PDO is broadly but not completely effect of ENSO).

Let me put this the other way around. How many more decades of increasing temperatures would you need to convince you that GW is happenning? Or would you just disbelieve the figures?

[tomclarke]

Simon -

Back to what I think is the most constructive part of this debate. You have two broad issues with the altimeter data:

(1) It is wrong/ too innacurate/fudged
(2) You don't like the merged record (this you are now saying is the most interesting issue).

I am going to stick to (1) until either I agree with you, or you admit that you have no rational reason to disbelieve the data except your anti_AGW prejudices, or we reach some difference in assumptions which we can't resolve. Remember this is data from satellite altimeter team without an axe to grind.

Then we can move on to (2).

3. No reason given for the jump in drift rate.

5. What is the effect of large grid squares. i.e. inherent averaging over large areas. No mention.

6. What is "the average sea state" referred to? No mention.

7. How is the sea state in the area covered determined? No mention.

8. What is the lock range of the instrument and how does it drift over time and how do variations in lock range affect the instrument? No mention.

9. What is the total path loss and its variation? No mention.

10. What is the sensitivity of the instrument? What is the noise level? No mention.

11. How does signal stength affect errors. No mention.

I have deleted your points where satisfied, and also comparison with tidal gauges since that related to the merge issue.

A lot of your points seem to be queries about how the altimeters work, I expect I will need to go back to earlier references for these. I will get back to you.

To everyone else. You don't have to read this thread! I realise it must seem boring this examining of minute details. Not as much fun as bold dramatic statements in blogs.

Very true, but it is the way you work out what is going on in complex problems. I don't know any short-cuts, except to believe other people who do it. This whole debate is based on the fact that it seems many people don't believe the scientific consensus - to the extent where any scientific paper which supports it is regarded as probably wrong!

Tom

[PolyGirl]

Although they may have moved some geologically.

The lateral movement of the plates is typically at speeds of 50–100 mm annually[1] This value was around the time when plate tectonics became widely accepted (circa 1970)[2]. However further research since then yield that “Plate motions range up to a typical 10-40 mm/a”[3]. To “to about 160 mm/a”[4] and this is only just the lateral movement of the plates.

Consider the Tetonic uplift especially the Orogenic and Isostatic uplift (especially the last two paragraphs in the cited reference) and of course subsidence the opposite of uplift[5]

Once you have these combinations. One would definitely want to know that “these parameters” are taken in to account in regards with the “satellite data” and the “ground data” in calculating whether the oceans are rising and falling.

Regards
Polygirl

[1] Watson Janet (1975). Introduction to Geology. New York: Halsted. pp. 13–15.
[2] Kent C. Condie (1997) Plate Tectonics and Crustal Evolution: Butterworth-Heinemann, page 1
[3] http://hypertextbook.com/facts/ZhenHuang.shtml
[4] Hancock, Paul L; Skinner, Brian J; Dineley, David L (2000). The Oxford Companion to The Earth. Oxford University Press.
[5] http://en.wikipedia.org/wiki/Tectonic_uplift

[MSimon]

since I prefer to trust Hansen/GISS

Since Hansen has a very big AXE to grind ("Auschwitz Trains") I'm not so sure he is worthy of your trust.

[MSimon]

1) ENSO/PDO - currently cold. Can't predict certainly how effect of this will change since La Nina/El Nino etc events chaotic and cold/hot depends on which happens but current anomaly is -0.7C and very likely to change back to more + in next 12 months.

So true. But it evades the point on several levels.

1. Past sea level rise can be corrected for it
2. Past warming imputed to CO2 can be corrected for it
3. Past trendlines can be corrected for it

Now Tom - you have been evading this point since I first brought it up, you naughty boy.

BTW very pretty colorful charts. Still - bad science.

And since PDO/ENSO can't be predicted wouldn't you say that the climate boys don't know enough to make good predictions? BTW don't answer this until you answer points one through three above. Wouldn't want you getting distracted.

And of course we now have a mechanism for explaining how small changes in the sun's output can make much bigger changes in earth's climate. Svensmark. Proven in Copenhagen. Currently being verified at CERN.

And don't give me the "we can't be sure" crap re: Svensmark. That hasn't stopped the climate boys from GUESSING at water vapor parameters. We can start with something simple - like the sign. Then we can go on to more complicated stuff like the magnitude.

[MSimon]

PolyGirl,

Quite right!

[MSimon]

Tom,

I'm willing - for the sake of argument - to concede the altimeter data (except for record splicing) if you will answer the points brought up in:

viewtopic.php?p=20570#20570

Simon

[tomclarke]

Since Hansen has a very big AXE to grind ("Auschwitz Trains") I'm not so sure he is worthy of your trust.

Only the religious or the deluded are sure.

The references from the second altimeter paper are good and cover a lot of ground, but it is taking me some time to read them all. I will however answer the tidal gauage/altimeter difference issues which also relate to Polygirl's point.

I will look at the Svengali stuff too. There is lots of science there - though more unknowns.

[tomclarke]

So true. But it evades the point on several levels.

1. Past sea level rise can be corrected for it
2. Past warming imputed to CO2 can be corrected for it
3. Past trendlines can be corrected for it

Now Tom - you have been evading this point since I first brought it up, you naughty boy.

BTW very pretty colorful charts. Still - bad science.

And since PDO/ENSO can't be predicted wouldn't you say that the climate boys don't know enough to make good predictions? BTW don't answer this until you answer points one through three above. Wouldn't want you getting distracted.

And of course we now have a mechanism for explaining how small changes in the sun's output can make much bigger changes in earth's climate. Svensmark. Proven in Copenhagen. Currently being verified at CERN.

And don't give me the "we can't be sure" crap re: Svensmark. That hasn't stopped the climate boys from GUESSING at water vapor parameters. We can start with something simple - like the sign. Then we can go on to more complicated stuff like the magnitude.

Sure, I will answer this. But note there are some 10 refs from the second altimeter paper which answer your first set of points nicely. They are interesting. It is taking me some time reading them (I'm no scientist). I will post the most interesting of the answers here (particularly wrt tidal gauges vs altimeter) so all can see what happens if you go looking for what is real instead of believing uncritically sound-bites from blogs with an agenda!

[MSimon]

Tom,

I did not take my 3 points from any blog. They may be available elsewhere.

But as far as I know they are my own.

What I want to know is re: sea level rise is how the tidal gauges compare to the satellite data over the period of the satellite data.

The fact that a 100 (150?) year average is different from a 15 (17?) year average does not strike me as apples to apples since there are KNOWN cyclical processes in the HISTORICAL record. The fact that they can't be predicted is no bar to correcting the past.

In very simple terms: the average (integration actually) of sine 0 to sine pi/2 is not equal to the average of sine 0 to sine 2 pi.

BTW I'm with you relative to climate prediction. It can't be done with skill since we don't know all the SIGNIFICANT equations.

UV effect on the upper atmosphere is one - as one climate guy put it: "We parameterize it because it is too complicated". That is rather unphysical don't you think?

[MSimon]

BTW excellent evasion on Hansen.

Have you considered getting a spot at Real Climate? You can spend your time shooting down McIntyre and McKitrick. Beautiful job there don't you think?

[tomclarke]

http://www.ggy.bris.ac.uk/staff/persona ... report.pdf

Sea Level Rise During Past 40 Years Determined from Satellite and in Situ
Observations, Cecile Cabanes, Anny Cazenave, Christian Le Provost

There are about 10 references from the second altimeter paper relevant to Simon's and Polygirl's questions so I am going through them one by one, posting anything that each answers.

This paper is comparing altimeter & tidal gauge estimates and working out why they are different.

The 3.2 6 0.2 millimeter per year global mean sea level rise observed by the Topex/Poseidon satellite over 1993Ð98 is fully explained by thermal expansion of the oceans. For the period 1955Ð96, sea level rise derived from tide gauge data agrees well with thermal expansion computed at the same locations. However, we Þnd that subsampling the thermosteric sea level at usual tide gauge positions leads to a thermosteric sea level rise twice as large as the ÒtrueÓ global mean. As a possible consequence, the 20th century sea level rise estimated from tide gauge records may have been overestimated.

The point about the tidal guages is that they are not uniformly placed. They tend to be coastal.

This paper is quite clever. It tests the (simple) hypothesis that up to 1998 ocean height is mostly determined by thermal expansion. It finds:

(1) altimeter data correlates well with expansion expected from ocean temperature change.

(2) Tidal gauge data seems to have twice the expansion expected - indicating some problem.

(3) Taking ocean temperature just at the tidal guage positions and averaging also gives roughly twice the temperature change.

(4) Thus the anomaly is because the poor spatial resolution of the tidal gages mean they are not accuratelky reflecting averga behviour. (They are typically in selected geophysical areas, since nearly all coastal).

Note that this paper corrects an otherwise anomalously high estimate of ocean expansion over this Century from tidal gauges as opposed to satellite data. It explains one set of anomalies between satellite & tidal gauge averages.

it seems unlikely this is part of the AGW conspiracy?

[tomclarke]

Polygirl -

re tectonic movement etc.

Your points are interesting. I remember the altimeter paper saying something about calibrating using a set of (chosen to be tectonically more stable) positions, but I don't understand enough about the details of this process, nor about whether sideways vs vertical motion is relevant. I THINK that the satellite altimeter points directly towards the centre of the earth and bounces back a signal, so measuring distance from satellite to earth surface.

Also there is a paper I have not read yet about how they can get satellite orbital position to within 1cm.

My guess is they get the extra factor of 20 accuracy by averaging over many readings, and using known correlations. there is some clever stuff about that as well but it will need some reading. You could have a go if you like, the refs from the second (altimeter calibration) paper are the relevant ones. More later.

Tom

[MSimon]

Slide 7 of this power point presentation makes the point I have been making only more clearly:

http://wattsupwiththat.files.wordpress. ... dzen-3.ppt

from:

http://wattsupwiththat.com/2009/06/02/l ... ne-2-2009/

I'll get back to you on the paper you just posted after I have had time to look at it.

[MSimon]

Couldn't get the paper.

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /staff/personal/JonathanBamber/teaching/Env change II/sealevelreport.pdf.

Reason: DNS lookup failure for: localhost

Tom,

It doesn't matter if the tidal gauges report 2X the satellite rise or 1/2. What matters is: has the satellite record been corrected for PDO/ENSO so that we are not mistaking short term variation for long term trend.

You keep avoiding my main point lost in the minutia.

The purpose of comparing the two trends (tidal - satellite) is so we can make a stab at correcting for short term variation. That is how you properly splice the two records to determine if we are seeing something unusual.