2011-05-23 08:22:04Why SLR is not uniform
John Hartz
John Hartz
john.hartz@hotmail...
98.122.68.19

Where can I find a good explanation of why SLR does not occur uniformly throughout the planet's ocean system?

Because SLR does not occur uniformly throughout the planet's ocean, is there a standard method for computing average global SLR akin to how the Annual Global Mean Temperature is computed?

Has the issue of the non-uniformity of SLR been addressed in a stand-alone SkS blog post? [If it hasn't, I volunteer to take a crack at drafting one.]

2011-05-23 08:27:33
oslo

borchinfolab@gmail...
90.149.33.182

Here's a nice presentation by Jerry Mitrovica on the issue - youtube link - a longer version is also available.

I belive he has some papers on this as well.

A good article on this at e360:

The Secret of Sea Level Rise: It Will Vary Greatly by Region

2011-05-23 09:00:22
oslo

borchinfolab@gmail...
90.149.33.182

>I belive he has some papers on this as well.

Two papers on this site (2010) - Mitrovica participate on the Greenland article and Stouffer (mentioned at e360) on the other one.

2011-05-23 11:06:36
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

@ Badgersouth

I volunteer to take a crack at drafting one.

Go for it.  I believe the most recent SkS posts on SLR are here and here, but (as you point out) they do not dealt with non-linear SLR.

News article here and source paper here may be of assistance.

Cry havoc!

2011-05-23 12:03:21
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.4.231

Excellent Badger, this has been on my long list of topics to cover, guess I can cross it off now!. I'll be very interested to see what you come up with.

This is the paper of sea level fingerprinting of the West Antarctic, which appears in Jerry Mtrovica's talk. But I like a paper Kuhn 2010 too, which has some nice graphics.

Oslo - thanks for the link to Mitrovica's talk. It reminded of of something, that crappy paper on Greenland ice sheet (the one with Pat Michaels as one of the co-authors), what did the early 20th century regional SLR look like compared to today?   

2011-05-23 14:05:40
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

From FKM 2011:

The forces acting in concert with ice melt across Greenland to produce higher global sea levels currently, should also have been acting during the extended high‐melt conditions from the mid‐1920s to the early 1960s. There is some qualitative indication of an observable influence of the variations in input from Greenland in the decadal rates of sea level change over the course of the past century [Jevrejeva et al., 2006; Church and White, 2006].

However, there is no indication that the increased contribution from the Greenland melt in the early to mid 20th century, a roughly 40 year interval when average annual melt was more or less equivalent to the average of the most recent 10 years (2000–2009), resulted in a rate of total global sea level rise that exceeded ∼3 mm/yr.

This suggests that Greenland’s contribution to global sea level rise, even during multidecadal conditions as warm as during the past several years, is relatively modest.

From Church & White 2011:

C&W SLR 1860-2009

2011-05-23 15:24:32
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.5.97

Yooper, that's global mean sea level. The FKM quote is not very enlightening, AFAIK neither Church & White 2006, nor Jevrejeva 2006, look at sea level 'fingerprinting'. It's clear there was an acceleration in SLR in the early 20th century, but where did it come from? What was the contribution of the GIS melt to SLR throughout the 20th century? Be interesting to see that plotted, but from my reading on the topic thus far, sounds terribly complex, and the datasets not too flash. 

2011-05-23 22:16:02
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

The FKM quote was from the conclusion, and was the only time (that I could find) they quantitatively reference SLR.  And even that was an indirect drive-by smear.

AFAIK, any attributions to SLR "fingerprinting" prior to 1970 or so are limited by poor datasets.  Even with datasets post-2003 some people bitch about component attribution of SLR.  There's probably a few papers on it I'm not aware of, though.

IMHO, the quiescent sun of the recent minimum has been offset by increased melt of ice sheets.  Thus, while OHC seemingly has "flattened", melt has increased, keeping the SLR chart on course trajectory.  So a smaller component of SLR is due to thermal expansion and a larger portion is due to increased runoff from the melt, which is why the SLR graph above is not flattening.

If I'm correct (and I'd rather not be), then the awakening sun and the summer loss of Arctic sea ice will help to ramp up OHC and SLR.  And then the nonlinear increases in SLR will become evident.

If you feel strongly about it I can email Mauri Pelto or Jason Box.

2011-05-24 06:51:49
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.100.186

Cheers Yooper. No, don't feel that strongly about it, no need to bother either Box or Pelto. Actually, I hadn't given that much thought to the loss of summer sea ice speeding up ocean warming. Thanks!

Skimming some of the studies on the Antarctic bottom water, reveals that heat can propagate through the deep ocean far quicker than previously thought. I suspect we're seeing some kind of re-organization down deep. We're still unable to account for the extremely warm seas at high latitudes in the past, as there's no known mechanism that would transport heat from the tropics to the poles on such a scale in order to match the equator-to-pole temperature gradients observed. Kerry Emanuel or Federov?, have suggested increased cyclonic activity as a contributory mechanism, but man that would have to be an awful lot of hurricanes!.

It would certainly be worth a post at some stage, I think. That OHC is a real head scratcher!  

2011-05-24 08:09:12
oslo

borchinfolab@gmail...
90.149.33.182

I found this presentation interesting regarding sea ice cover in the Arctic, and in relation to the 2007 extreeme melt.

Seminar: Climate Change and the Arctic Ice Cover

It seems albedo feedback is the most important regarding sea ice extent according to Donald Perovich.

(a bit OT but hopefully interesting)