2011-10-25 08:28:42The Last Interglacial Part Five - A Crystal Ball?
Steve Brown

brownsg@gmail...
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This is the concluding post of the Last Interglacial series.  Any comments and suggestions are appreciated.

http://www.skepticalscience.com/LIG5-1110.html

2011-10-25 09:42:13FYI
Daniel Bailey
Daniel Bailey
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Scaddenp made this comment on the thread already:

The timeline isn't that clear. It could be read to imply that Eemian precedes the Pleistocene rather than being part of it.

2011-10-25 09:59:00
jg
John Garrett
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Good catch. I'll fix that timeline/pleistocene thing.

2011-10-25 17:41:18
Glenn Tamblyn

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Good post - I like what the first diagram is trying to say. Unfortunately I don't think it is saying it vvery clearly. The diagram has too much stuff in too small a space. Perhaps break into 2 halves with the hemispherical insolation lines (and perhaps temps as well), then the graphics or the planet further removed. Also the 2 different timelines, Top & Bottom doesn't work. It is hard for a more lay reader to picture the correlation between them and what this means. And the use of Kya. Although technically correct isn't clear to a layman - 'Whats a KYA, is that a  car from Korea?'. Perhaps just numbers like 126 and a note at the bottom that all numbers are in 1000's of years.

2011-10-26 09:52:48Too much inside baseball
John Hartz
John Hartz
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As drafted, the article will be digetabole for only a small subset of the SkS readership because it presumes a fairly broad understanding of scientific concepts and terms.

For example, here's the current version of the first paragaph.

"Comparing the climatic controls of the Last Interglacial with those assumed in future climate projections is problematic owing to fundamental differences, especially orbital forcing, seasonal warming, and greenhouse gas concentrations.  Palaeoclimatic studies show that differences in orbital parameters during the Last Interglacial are sufficient to explain the higher temperatures over most parts of the Northern Hemisphere, particularly due to greater obliquity and eccentricity compared with the present day orbital configuration.  This greater obliquity provided stronger insolation at high latitudes and weaker insolation at low latitudes.  Perihelion occurred during summer in the Northern Hemisphere, which amplified seasonal insolation, while perihelion occurs in winter during the present day.  Figure 1 shows a comparison of Eemian and Holocene summer insolation.  Peak insolation from orbital forcing will be significantly lower over the next century than what the Earth received during the climatic optimum at ~126 ka."

What are "obliquity, eccentricity, insolation"? (I know because I read the prior articles. Many SkS readers will not have done so.)  

What the heck is "perihelion"? (I haven't the foggiest.)

What is the "climatic optimum"? (I don't know.)

What is "ka"? (I know it stands for thousands of years ago. Why not just say "about 126 thousand years ago?")

 

2011-10-26 12:06:02
jg
John Garrett
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Good coments. I'm waiting to hear what Steve has to say before I start revising the illustration, except for changing kya --sometimes spelled ka :) -- to something better.
2011-10-27 08:05:04
Steve Brown

brownsg@gmail...
94.174.78.42

Yes, very good comments.  I was under the romantic delusion that all SkS readers would have carefully studied all the previous posts in the series plus the spin-off post by Chris Colose on Milankovitch forcing before reading this one - and thus be au fait with the finer points of orbital mechanics and insolation :-(

I'll aim to get a simpler version of the offending passages up by the weekend.

jg - could you please split the figure 1 diagram into two with the Holocene and the Eemian separated out one above the other?  That should go a long way to making it easier to understand.  Also remove the references to ky and kya and replace with an axis label of "x 1000 years".  An additional Eemian and Holocene comparison sketch of this might be worthwhile too: http://www.skepticalscience.com/pics/Orbit_130_125kya_lg.jpg

Thanks!

2011-10-28 06:23:50
jg
John Garrett
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98.112.44.162

Hi Steve. I'll work on the changes. What's your release date? I won't be able to work on this for a few days.

jg

2011-10-28 07:21:43
Steve Brown

brownsg@gmail...
94.174.78.42

jg - no rush.  I've started my postgrad studies and going through a busy period at work, so enough on my plate at the mo.  knowing that I'm waiting on you makes me feel less guilty ;-)

2011-10-28 09:11:16Steve
John Hartz
John Hartz
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Perhaps you should put together a brief Glossary of Terms and append it as a box to each of the articles in the series.

2011-11-09 07:48:02
jg
John Garrett
garrjohn@gmail...
98.112.44.162

Steve,

Here's an animation to break up the holocene/eemian comparison. I should stretch out the timing, but this invites others to comment as to whether it can work.

2011-11-11 00:20:39
Steve Brown

brownsg@gmail...
77.102.28.54

OK, this is the final version with jg's updated graphics.  I've created a link from the figure 1 graphic to the final version of the animation that jg produced.  I think it's the best compromise between retaining the visualisation that jg orignally intended and making it user friendly.

I'm now flying to Melbourne from the UK, so will be out of circulation until the weekend at least.

2011-11-11 11:35:32Quick question on authorship
John Cook

john@skepticalscience...
130.102.158.12
Considering jg's substantial contribution, what about adding dual authorship to this post? Just needs one of us admins to update the post for you.
2011-11-12 02:08:09Someone w/ the ability to do so
John Hartz
John Hartz
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98.122.98.161

Please change the neon green background in the top and bottom boxes to the SkS standard soft green.

2011-11-13 22:02:35
Steve Brown

brownsg@gmail...
203.63.65.169

JC - Of course jg should have co-authorship.  I would have done that already if I was able to.

2011-11-14 02:55:27
Daniel Bailey
Daniel Bailey
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97.83.150.37

Added jg to the author line.  I'll look into the box background color thingy in a bit.

2011-11-14 03:20:21
Daniel Bailey
Daniel Bailey
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97.83.150.37

Fixed the boxes.