2011-07-06 16:48:51Thinning on top and bulging at the waist: symptoms of an ailing planet
Andy S


Draft here

I have written this fairly quickly, so some critical reading would be gratefully received.

If anyone wants to see a copy of the Nerem and Wahr paper, please email me at agskuce@gmail.com 

2011-07-06 19:53:39


Nice post and interesting reasearch by Nerem and Whar for the yet one more use of GRACE data. Here is the correct link to the paper in press: http://www.agu.org/journals/pip/gl/2011GL047879-pip.pdf

There's no need to add the yellow line in fig. 1, the decreasing trend is pretty clear. As in the paper, say that the conclusions are insensitive to the GIA model used.
I think you may drop fig. 2 and just link to it
In the concluding paragraph, I'd highlight that different kind of measurements confirm each other making the overall picture coherent.
The joke of the hokey stick is nice but call it the mini-hockey stick league to make it clear that it's just a joke.

2011-07-06 22:08:12


That's great Andy S.  To add to your narrative about the "middle-aged" Earth, you could put something like, "Like many an aging baby boomer, that isn't in peak condition..." -- not those words, but something to metaphorically tell the reader that this is a cause effect relationship, ie, if we weren't actively changing the atmosphere, the Earth wouldn't be getting fatter.  :)

2011-07-07 01:39:01
Dana Nuccitelli

Figure 1 kind of comes out of the blue.  I'd suggest moving it below the discussion of what J2 is.  And I agree with Riccardo that the yellow line is unnecessary.  Interesting post though.

2011-07-07 04:36:21Suggested Tweak
John Hartz
John Hartz

Andy S,

The last sentence of your first paragraph reads:

"Rather, it is because of climate change. As the big ice sheets in Greenland and Antarctica melt, the melt water is distributed relatively evenly over the world’s oceans, causing mass to move away from the poles."

I suggest it be tweaked to read:

"Rather, it is because of climate change. As the big ice sheets in Greenland and Antarctica melt, the melt water is distributed throughout the world’s oceans, causing mass to move away from the poles."

2011-07-07 05:04:42Recommendations
John Hartz
John Hartz

Andy S

As I understand it, the increaing oblateness of the world's oceans means that SLR tends to be concentrated in the equatorial regions of the world's ocean system. This directly ties to the fact that SLR due to increased ice melt is not uniformly distributed throughout the ocean system. These points should be explicitly stated in the article. 

You may also want to reference and link to JPL's Sea Level Viewer

2011-07-07 05:28:13
Andy S


Thanks, everyone.

Riccardo and Dana, I took your advice and removed the yellow line. It was indeed unnecessay but I'm used to presenting stuff to corporate types with limited attention spans for whom underlining the obvious is never redundant. Actually, this line was also confusing since the original authors did not uses a simple residual to a straight-line fit but instead used a GIA model.

Riccardo: I fixed the link (which was wrong) but did not use yours since, for non-subscribers to AGU journals, that leads to a log-in page. As yet, there is no free abstract because the article is in press. I'll fix that when it comes out, if I remember.

I felt that I needed to show Figure 2 because the mid-1990's tipping point in Greenland ice-melt is important information that is independent of the measurements made in the Nerem and Wahr paper. Besides, I always like to show as well as tell.

I toned down the hockey-stick stuff and took the reference out of the title.

Badger, thanks, I used your suggestion.

Grypo, I couldn't find the right words to extend my metaphor/joke without sounding silly. I'm open to suggestions, though.

Everyone, I must say that I am disappointed with the standards of SkS peer review. Nobody spotted that I had gotten the names of the GRACE satellites (Tom and Jerry) inverted with Jerry chasing Tom in my original draft. Imagine the embarrassment this would have caused had this error been exposed by the auditors. ;-)

2011-07-07 06:04:11
Andy S


Badger (second comment):

There are many reasons that sea level rise is uneven, including secondary effects of GIA (such as forebulge collapse, see here ), salinity, local uplifts and subsidence, ocean currents, and odd gravity effects like this. There's even the probability that the axis of rotation will move and the bulge with it. I thinks it's worth explaining all this in another post but I felt that I would be over-complicating this post and I wanted to keep to JC's approach of keeping the posts restricted to one message at a time.

2011-07-07 08:38:09Andy S
John Hartz
John Hartz

You may want to collaborate with Rob Painting on the second post about SLR. It is definitely needed.

2011-07-07 09:16:05
Rob Painting

Maybe the odd word here and there is still a bit boffin-like, but nice post. Thumbs up from me!

2011-07-07 10:02:05Boffin like
John Cook

Some of it is a little boffin like but I really like the metaphor and how you led off with your core message in the first line. So good stuff.

BTW, I LOLed at Gin and Tonic's "the oblate spheroid is becoming an obese spheroid". Makes a good (albeit geeky) punchline coupled with the thinning/bulging metaphor if ever used in a public talk.

2011-07-07 10:19:12
John Hartz
John Hartz