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  1. #38581
    Steve Case Steve Case is offline
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    Quote Originally Posted by owedtojoy View Post
    But you still prefer the limitations of local tide gauges to the
    planetary coverage and accuracy of satellite laser altimetry.

    Because you can frig around with the tide gauge data in Excel
    until it gives you the answer you want i.e. there is a Commie
    conspiracy to make you ride a bicycle.
    I run CU's data through excel as well, and I find that they've
    bumped up the rate nearly a full millimeter per year since 2004.
    Nor does their data show acceleration. If there is any due to
    the range of uncertainty as you like to claim, it isn't very much
    and certainly not nearly enough to get you to the catastrophic
    flood tide hobgoblin you need to scare the bejesus out of the
    general populace.
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  2. #38582
    barry schwarz barry schwarz is offline

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    Quote Originally Posted by Steve Case View Post
    But do they adjust data from
    individual stations? I don't know. I'm not suspicious of any
    adjustments they make. But I am suspicious of CU's manipulations.
    It's only one or two instruments and a few guys in control.
    And as you acknowledge, it doesn't seem to agree with the tide
    gauges. But if you take out the 0.9 mm/yr of corrections it does.

    Waves? Tide gauges use stilling wells. Wikipedia
    tells us microwaves are 0.3 - 300 cm long. Resolution is
    1/4 wave length so (.25 x 3 mm = 0.75 mm) is possible.
    And you want to tell me it's accurate to 0.04 mm/yr?
    Here's one paper on the errors inherent in the tide gauge record.

    http://scientiamarina.revistas.csic....File/1386/1490

    The land-based tide gauge record is affected by vertical changes in the land. Tide gauges are measuring land changes as well as ocean, and the distribution of this artefact is not symmetircal (up and down movements of land around the world do not cancel out - the preopnderence of long-term tide gauges are in the NH, in areas experiencing crustal lift). All the studies I've read mention the sparseness of the data, even along coastlines, never mind that the vast ocean surfaces are not covered. Changes to instrument location and type over the years has to be accounted for. A sinking pier is not going to reflect sea level change. Most record have gaps, some very large, so infilling must be done, or work with an even patchier record, and like the satellite records, homogenisation is applied to remove seasonal and other effects.

    Sea level height is measured by the distance between the sensor and the ocean skin. each individual sounding has a 2-3 cm error. For comparison, the tide gauge error is about 1.5cm. The law of large numbers really applies here, as there are millions of data points for every orbit a satellite does. Verification checks are done with individual tide gauges (satellite v tide gauge at specific location). Comparisons with GRACE, a totally different method (gravity) for estimating sea level, provides excellent agreement with the satellites. There are 5 different satellite-based sea level records using different methods which very closely agree. There are many adjustments and biases that must be accounted for. Orbital drift and decay are issues. OTOH, where the global tide gauge series is based on many different sensors (each tide gauge with its unique history of instrumental and land changes), there are comparitively very few sensors measuring a much broader area - a much more homogenous measuring system.

    Both types of sea level recording have issues. Weighing the issues in detail and determining their relative strengths and weaknesses is beyond me. I think the greater coverage - by many orders of magnitde - of the satellite measuring system is strongly in its favour. But, as I say, neither is definitive. I see no compelling reason, however, to prefer the tide guage record as you do. The various tide guage estimates (1.4 - 2.4mm/yr) diverge by much more than the satellite data sets (3.2mm/yr - 3.2mm/yr). I would be skeptical about both.
    Last edited by barry schwarz; 2nd April 2014 at 08:29 AM.
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  3. #38583
    barry schwarz barry schwarz is offline

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    Quote Originally Posted by Steve Case View Post
    I suppose you're going to tell me about the power of large numbers again.
    Global tide gauge sea level and error bars rely on it. How do you imagine an averaging process works?



    Non-sytematic errors average out with many iterations.
    Last edited by barry schwarz; 2nd April 2014 at 04:19 AM.
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  4. #38584
    barry schwarz barry schwarz is offline

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    Quote Originally Posted by Steve Case View Post
    I run CU's data through excel as well, and I find that they've
    bumped up the rate nearly a full millimeter per year since 2004.
    Nor does their data show acceleration. If there is any due to
    the range of uncertainty as you like to claim, it isn't very much
    and certainly not nearly enough to get you to the catastrophic
    flood tide hobgoblin you need to scare the bejesus out of the
    general populace.
    No one is making any claims about rate changes over the 22-year satellite record except you. You're talking to yourself here.
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  5. #38585
    Agnotologist Agnotologist is offline

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    Feeling the need to be depressed, I watched the second installment of "Tipping Points" this evening. This episode was on the Amazon Rainforest.'

    The most striking part was an experiment on the effects of drought. An area was covered to reduce the moisture levels to 50% of normal. Within a few years. trees began to fall and in ten the large trees were dying and falling. The large trees fell first. Trees that were thousands of years old.

    Areas that have been already changed to savannah were looked at - substantial areas. What were once hundred year droughts have occurred twice in seven years.

    Controlled burns to see the rate of recovery produced savannah that did not recover. The former belief that the Rainforest "liked" heat was shown to be wrong. More heat led to faster deterioration.

    The projected temperature increase of 3-4 C this century was said to be enough to kill the rainforest, or. at least, to transform it into something entirely different.

    One of the reasons for drought was said to be the warming Atlantic and Pacific oceans that draw moisture from the Amazon area. An El Nino may help Texas but it will kill many more trees and, already, hundreds of millions have died.

    In summarry, the Rainforest is well on the way to becoming a carbon emitter rather than a vast sink.
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  6. #38586
    correr correr is offline

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    Quote Originally Posted by Agnotologist View Post
    Feeling the need to be depressed, I watched the second installment of "Tipping Points" this evening. This episode was on the Amazon Rainforest.'

    The most striking part was an experiment on the effects of drought. An area was covered to reduce the moisture levels to 50% of normal. Within a few years. trees began to fall and in ten the large trees were dying and falling. The large trees fell first. Trees that were thousands of years old.

    Areas that have been already changed to savannah were looked at - substantial areas. What were once hundred year droughts have occurred twice in seven years.

    Controlled burns to see the rate of recovery produced savannah that did not recover. The former belief that the Rainforest "liked" heat was shown to be wrong. More heat led to faster deterioration.

    The projected temperature increase of 3-4 C this century was said to be enough to kill the rainforest, or. at least, to transform it into something entirely different.

    One of the reasons for drought was said to be the warming Atlantic and Pacific oceans that draw moisture from the Amazon area. An El Nino may help Texas but it will kill many more trees and, already, hundreds of millions have died.

    In summarry, the Rainforest is well on the way to becoming a carbon emitter rather than a vast sink.

    Makes a change from depressing us with your climate scam crap.
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  7. #38587
    Steve Case Steve Case is offline
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    Quote Originally Posted by barry schwarz View Post
    Global tide gauge sea level and error bars rely on it.
    How do you imagine an averaging process works?

    I used the example of measuring 30 squares of gelatin dessert
    with a rubber yard stick. You could average that all up and
    probably get an answer to as many places as you like. x.xxxxxxx......
    If your rubber yard stick has graduations as fine as 1/16 of
    an inch, how accurate, x.xx..." do you think it would be?
    What if you measured a million Jello squares? You are
    wanting to make a silk purse from a sow's ear.
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  8. #38588
    Steve Case Steve Case is offline
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    Quote Originally Posted by barry schwarz View Post
    No one is making any claims about rate changes over the 22-year satellite record except you. You're talking to yourself here.
    There's that pdf file "Why has an acceleration of sea level rise not been observed during the altimeter era? " a presentation by Dr. Steve Nerem that I keep throwing in your face.
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  9. #38589
    Steve Case Steve Case is offline
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    Quote Originally Posted by barry schwarz View Post
    Here's one paper on the errors inherent in the tide gauge record.

    http://scientiamarina.revistas.csic....File/1386/1490

    The land-based tide gauge record is affected by...
    I was not impressed by the paper after I saw the photograph
    of all their stuff sitting out in the open. And they used a
    tide pole? That's what, a stick stuck in the mud?

    I started to take some notes while going through your link:

    we estimated an upper b1ound for the radar instrumental error
    in field condition at ~0.3 cm.


    that's 3 mm and exactly what's the radar instrument? Satellites?

    Many tide gauges that are perfectly suitable for harbour operations
    provide data that are not accurate enough for long-term sea level studies.

    Nice assertion, no reason given why.

    Radar tides gauges in particular stood out as a promising
    option in terms of accuracy and ease of operation

    with an error of 3 mm?

    I have this image in mind when I think of a tide gauge,
    so I googled tide gauge images and this schematic is
    about what I think the things should look like:



    A sturdy enclosure, a stilling well with the instrument,
    some electronics and telemetry is what I had in mind.

    Maybe reality is cruder than that.
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  10. #38590
    barry schwarz barry schwarz is offline

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    Quote Originally Posted by Steve Case View Post
    I used the example of measuring 30 squares of gelatin dessert
    with a rubber yard stick. You could average that all up and
    probably get an answer to as many places as you like. x.xxxxxxx......
    If your rubber yard stick has graduations as fine as 1/16 of
    an inch, how accurate, x.xx..." do you think it would be?
    What if you measured a million Jello squares? You are
    wanting to make a silk purse from a sow's ear.
    A law with mathematical proof is not a sow's ear. You can complain about it all you like but it doesn't change the facts. It's such a basic probability calc, and it's so endemic to analysis of large data fields, which you rely on whenever you process data, that it is quite bizarre to see you rejecting it. If you measure a million jello squares that are the same size with rulers of different fineness, you'll get a better estimate of the true than if you measure one jello square with one ruler. The precision will increase the more measurements you take. It's not only intuitively perceivable, it's mathematically proven. Google it.
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