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  1. #20991
    Steve Case Steve Case is offline
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    Quote Originally Posted by owedtojoy View Post
    You may underestimate the statistical work involved
    in merging tidal gauge and satellite data.
    They aren't the same. Trying to make one match the
    other is a fool's mission.

    Quote Originally Posted by owedtojoy View Post
    On the other hand, I know scientists are not infallible
    Yes, they can be corrupted.

    Quote Originally Posted by owedtojoy View Post
    I saw a statement in a Nenem paper we can both agree with.
    The satellite sea level data as yet shows no sign of an accelerating
    sea level rise.
    That's right hasn't accelerated these last 20 years.
    Their current data shows a higher rate for the first
    ten years by the way. Check it out.

    Quote Originally Posted by owedtojoy View Post
    Nenem reckons more date is required. OTOH, sea level rise is
    NOT decelerating.
    For practical purposes it's a linear around 2 mm/yr.

    Quote Originally Posted by owedtojoy View Post
    We need to let it plod along for a few more years & see what
    happens. In my view, as the ice caps melt, sea level cannot
    do anything else but rise.
    And they are rising, they just aren't rising faster & faster.
    Last edited by Steve Case; 1st February 2013 at 08:57 PM.
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  2. #20992
    owedtojoy owedtojoy is offline
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    Quote Originally Posted by Steve Case View Post
    They aren't the same. Trying to make one match the
    other is a fool's mission.


    Yes, they can be corrupted.


    That's right hasn't accelerated these last 20 years.
    Their current data shows a higher rate for the first
    ten years by the way. Check it out.


    For practical purposes it's a linear around 2 mm/yr.


    And they are rising, they just aren't rising faster & faster.
    Nah. I'll go with the science - just over 3mm/ yr. You can stick with your fond wishes.

    Of course tide gauges and satellite are "not the same". But from my own brief reading, I can understand in outline from the papers I looked at how they can be aligned. It depends on collecting data simultaneously for a while. Then from the cross matching of the data in suitable cells in space (they use 1 degree latitude x 1 degree longitude) and in time (1 month), they use Bayesian methods for the distributions of the oceanic measurements, given the tide gauge readings. They then apply the statistical "learning" to the older tidal data. Easier to describe than to do. It could not be done in one go, and could keep a statistician busy for a good part of his career.

    Don't know about you, but to me the rates of sea level rise in the second half of the 20th century look distinctly higher than those in the first half (on average, of course). That 35-year smooth tells the story.

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  3. #20993
    owedtojoy owedtojoy is offline
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    There used to be a "argument" going around about earth warming "Mars is warming too, so it must be the sun".

    We don;t hear that one any more, but NASA released a fascinating video about carbon dioxide on Mars. Any "warming" there seems to be due to the planet's orbital variations.



    Martian melting – A Few Things Ill Considered
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  4. #20994
    Agnotologist Agnotologist is online now

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    I don't think this has been posted yet. Jason Box's look at the future of ice.

    Humans have already set in motion 69 feet of sea-level rise | Grist
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  5. #20995
    owedtojoy owedtojoy is offline
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    Quote Originally Posted by Agnotologist View Post
    I don't think this has been posted yet. Jason Box's look at the future of ice.

    Humans have already set in motion 69 feet of sea-level rise | Grist
    Here is what 69 feet of sea level rise looks like on the coast of the US:



    The “good” news is that this might take 1000 to 2000 years (or longer), and the choices we make now can affect the rate of rise and whether we blow past 69 feet to beyond 200 feet.

    Manmade Carbon Pollution Has Already Put Us On Track For 69 Feet Of Sea Level Rise | ThinkProgress
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  6. #20996
    Steve Case Steve Case is offline
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    Quote Originally Posted by owedtojoy View Post
    Here is the way I obtained the chart below.

    I aggregared all the tide guage sea level
    anomalies into years rather than months.

    Using Excel's SLOPE() function, I got the
    linear slope of every 10-years of data.
    That gave me 123 data points from 1879 to
    2001 - the "X"'s in the chart below.

    Then I fitted a LOESS 35-year smooth to the
    data and got the red line.

    The red point and errors bars were fitted
    from the satellite data.]



    LOESS (Locally Estimated Sum of Squares)
    is a standard smoother, and is not an Excel
    function. However, Jon Peltier has designed
    a useful (and free) add-in. This is the 3rd
    time I have told you about it. Go here
    LOESS Smoothing in Excel | Peltier Tech Blog | Excel Charts

    You seem to estimating 35-year slopes and
    over-smoothing the data.

    PS Note that for most of the 20th century,
    while sea level rates have fluctuated, they
    have almost always been positive.
    Thanks once again for the link to your
    LOESS page.

    I've been looking at what you did on that chart,
    and the one thing that sticks out is the data
    you used. It's Church & White (2006) which
    is the opus I have the most issues with. As you
    know Church & White list the tide gauge stations
    they used
    Zip C&W Tide Gauges
    I've put critiques of that up before, but I looked
    at it with your ten year slope averaging technique
    you describe giving you those 123 data points.
    So I processed the C&W stations and ALL the stations
    in the exact same manor and looked at just the last
    ten years which coincides with the satellite era
    quite nicely and here's what I find:

    Code:
     Ten Year Slope & Difference
    
    YYYY ... ALL .... C&W ... Delta	
    
    1992 ... 1.76 ... 1.55 .. -0.20
    1993 ... 1.14 ... 0.79 .. -0.35
    1994 ... 1.00 ... 0.56 .. -0.44
    1995 ... 0.84 ... 1.37 ... 0.53
    1996 ... 0.71 ... 1.77 ... 1.06
    1997 ... 0.72 ... 1.38 ... 0.66
    1998 ... 0.54 ... 1.87 ... 1.33
    1999 ... 1.65 ... 2.57 ... 0.91
    2000 ... 2.22 ... 3.29 ... 1.07
    2001 ... 3.25 ... 4.02 ... 0.77
    			
    Average .................. 0.53
    The Church & White selection of stations yields a
    significantly higher average rate of sea level rise
    (0.53 mm/yr) for those ten years. By the way, the
    tide gauge data is listed with (C&W 2011) So while
    I may have said earlier that their 2011 opus seems
    a bit more realistic I am speaking of their final
    treatment, not the selection of initial data.
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  7. #20997
    owedtojoy owedtojoy is offline
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    Quote Originally Posted by Steve Case View Post
    Thanks once again for the link to your
    LOESS page.

    I've been looking at what you did on that chart,
    and the one thing that sticks out is the data
    you used. It's Church & White (2006) which
    is the opus I have the most issues with. As you
    know Church & White list the tide gauge stations
    they used
    Zip C&W Tide Gauges
    I've put critiques of that up before, but I looked
    at it with your ten year slope averaging technique
    you describe giving you those 123 data points.
    So I processed the C&W stations and ALL the stations
    in the exact same manor and looked at just the last
    ten years which coincides with the satellite era
    quite nicely and here's what I find:

    Code:
     Ten Year Slope & Difference
    
    YYYY ... ALL .... C&W ... Delta	
    
    1992 ... 1.76 ... 1.55 .. -0.20
    1993 ... 1.14 ... 0.79 .. -0.35
    1994 ... 1.00 ... 0.56 .. -0.44
    1995 ... 0.84 ... 1.37 ... 0.53
    1996 ... 0.71 ... 1.77 ... 1.06
    1997 ... 0.72 ... 1.38 ... 0.66
    1998 ... 0.54 ... 1.87 ... 1.33
    1999 ... 1.65 ... 2.57 ... 0.91
    2000 ... 2.22 ... 3.29 ... 1.07
    2001 ... 3.25 ... 4.02 ... 0.77
    			
    Average .................. 0.53
    The Church & White selection of stations yields a
    significantly higher average rate of sea level rise
    (0.53 mm/yr) for those ten years. By the way, the
    tide gauge data is listed with (C&W 2011) So while
    I may have said earlier that their 2011 opus seems
    a bit more realistic I am speaking of their final
    treatment, not the selection of initial data.
    As I understand it, C&G did not make a random sample, or even claim to make a random sample. Nor did they cherry-pick.

    From the notes with the file:

    These locations are on a 1 degree x 1 degree grid, to correspond with the grid that the satellite altimeter data is on. A location can have one or more tide gauge records mapped onto it.
    The selection critieria for tide gauges are given in their 2004 paper - they are trying to link the tide gauges with the spatial variability of the satellite data, so as not to bias the results with using too many gauges in some areas, and few in others.

    http://journals.ametsoc.org/doi/pdf/...O%3E2.0.CO%3B2

    I have not had time to read this yet, so it will have to wait.
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  8. #20998
    Earthling Earthling is offline
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    Quote Originally Posted by Steve Case View Post
    In the video Jason Box says that each year Greenland contributed 1.6 mm
    to sea level rise, and land ice almost as much and Antarctica about half as
    much or about 3 - 4 mm of sea level rise per year.

    Why do these guys have exaggerate everything? The Climate Desk interviewer
    just sat there nodding his head. The logical question to have been asked would
    be to point out that neither the satellite nor tide gauge records support the
    3-4 mm/yr figure and how does that square with what Box just said?
    Catastrophists can make any figure fit anything, they hope no one will notice and in so doing, they achieve the intended goal of frightening even more people.
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  9. #20999
    Steve Case Steve Case is offline
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    Quote Originally Posted by owedtojoy View Post
    As I understand it, C&G did not make a random sample,
    or even claim to make a random sample. Nor did they
    cherry-pick.

    From the notes with the file:

    The selection critieria for tide gauges are given in
    their 2004 paper - they are trying to link the tide
    gauges with the spatial variability of the satellite
    data, so as not to bias the results with using too
    many gauges in some areas, and few in others.

    I have not had time to read this yet, so it will have
    to wait.
    I've been through the 2004 paper

    Estimates of the Regional Distribution of Sea Level Rise over the 1950–2000 Period

    I gleaned some numbers and put them into
    tabular order as follows:

    Code:
    Record..Status..........Reason
    
    1159....RLR	
    1950....Met	
    
    -256....eliminated......Records >2 years
    -1063...eliminated......Redundant
    -95.....eliminated......beyond TOPEX/Poseidon range
    -37.....eliminated......<250 km to Alt grid point.
    
    1658....records for further assessment.	
    
    ??......eliminated......Disagreement nearby records
    ??......eliminated......Locations
    ??......eliminated......Fragmented
    ??......eliminated......Noise
    ??......eliminated......Residual trends <10 mm/year
    
    -713....Eliminated......For above 5 reasons? (1658-945=713)
    
    945.....combined	
    
    -491....eliminated......by combination
    
    454.....records for further assessment.
    
    -28.....eliminated......No useful data
    
    426.....records for further assessment.
    Comments:

    Really, because Topex/Poseidon didn't cover the range they
    tossed the data? I don't think that makes sense, but I
    suppose there's a reason for that.

    In the text they go from 1658 records down to 945 records
    but don't give us any numbers as to how many were eliminated
    for the five reasons tabulated above. Residual Trends
    <10 mm/yr is reasonably objective. The other four listed are
    somewhat subjective without any guidelines as to what
    constitutes unsuitable locations, too much noise, too much
    fragmentation, or how much disagreement with other records
    is allowed or how near by they must be. After combining the
    945 records there was another group of records eliminated for
    having no useful data. What was not useful? As far as I’m
    concerned, there is room for some subjectivity in perhaps
    several hundred deletions of data.
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  10. #21000
    Earthling Earthling is offline
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    Quote Originally Posted by owedtojoy View Post
    I aggregared all the tide guage[sic] ..


    What the heck is a "guage" when it's at home?
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