Thursday
Apr072011
by 
Bishop Hill
Bishop Hill It's the ocean, stupid!
Apr 7, 2011 Climate: Models Jeff Id gave up blogging a few months back, but fortunately for us he just can't resist the urge to return from time to time. According to RP Snr, what he has said today is pretty important:
If you were to transfer enough ocean energy directly to the atmosphere to create 4 degrees of atmospheric warming, how much would that change the average temperature of the Earth’s water?
Would you believe – 0.001 Degrees C of ocean temp change? The left side pancake wouldn’t look any different in Fig 1! Hell, it wouldn’t change if we were in another oceanic current inspired ice age — think about that.
Reader Comments (21)
So a tiny release of energy from the oceans could be responsible for all of the 0.6degC rise in global temperature over the last century. Does the IPCC understand fully the mechanisms causing energy flow from oceans to atmosphere? Of course they do. ☺
You are making a bit of a strange assumption here. Why do you think the heat is mixed over the whole volume of water?
The oceans are stratified.
Most people forget that 'global temperature' is not a real temperature, but is based on anomalies in different proxies. 71% of 'Global temperature' is based on SST (Sea Surface temperature, so the temperature of the water), and effectively the rest 'doesn't matter'. Ocean currents, even when total heat content does not change, impact the statistics. My guess is that for example the bigger gulf stream going north in the North Atlantic, changes both de SST and atmosferic temperature in the Arctic (and this is the area where most of the Global Warming occured.
MarcusB:
Have you even bothered to go over to read what RP Snr has on his site?
Of course I looked at what RP Snr said on his site. He simply says "this is important" and copies out a piece of the other post from Jef ID. Why do you think I didnt read it?
MarcusB: RP Snr also said the following:
As noted by Sam in the first comment, we have raised this issue also including in our papers
Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55.
http://pielkeclimatesci.files.wordpress.com/2009/10/r-334.pdf
Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335. http://pielkeclimatesci.files.wordpress.com/2009/10/r-247.pdf
Nothing new here for those who understand the mechanics of El Niño y La Niña. Maybe some day Jeff will discover that most of the CO2 on Earth is in the form of bicarbonate mostly locked up in rocks but is dissolved in the oceans as well.
And next maybe they will figure out over 75% of the surface of the world is water and exposed to the sun and an excellent heat sink. Wouldn't that be wonderful.
MarcusB -
Levitus et al. measure OHC over the top 700m of the ocean. As the surface area is approximately 335 million sq km (source), that's a volume of 235 million km^3. Using 1.025 g/cc as salt water density, mass comes to 2.4 x 10^23 kg. That's about 1/6 of what Jeff calculated for the total mass of the hydrosphere.
So change Jeff's ".001" to ".006" if you like. The qualitative conclusion stands.
If you disagree, can you please give an alternative quantification?
HaroldW
I'd be very careful with OHC if I were you. The current reconstructions are questionable, to put it politely. I don't think there is a reliable estimate for the 700m layer or the 2000m layer (ARGO) as yet. The most we can say is that ARGO shows very little upward trend since it became dominant (eg Josh Willis' recent preliminary and unpublished estimate of OHC increase equivalent to a forcing of 0.16W/m^2 for the period 2005 -2010.
The stand-out problem with all OHC reconstruction is the splice between older XBT data and ARGO that gives you an increase in OHC of about 8*10^22 J between 2003 and 2005 (NODC, after Levitus et al.2009) or the same between 2002 and 2004 (Lyman et al. 2010). See also Wijffels et al. 2008.
Levitus, S., J. I. Antonov, T. P. Boyer, R. A. Locarnini, H. E. Garcia, and A. V. Mishonov (2009), Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems, Geophys. Res. Lett., 36, L07608, doi:10.1029/2008GL037155.
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf
John M. Lyman, Simon A. Good, Viktor V. Gouretski, Masayoshi Ishii, Gregory C. Johnson, Matthew D. Palmer, Doug M. Smith, Josh K. Willis (2010) Robust warming of the global upper ocean, Nature, Volume: 465, Pages: 334–337 DOI: doi:10.1038/nature09043
http://www.nature.com/nature/journal/v465/n7296/abs/nature09043.html
http://www.indiaenvironmentportal.org.in/files/Robust%20warming%20of%20the%20global%20upper%20ocean.pdf
Wijffels, Susan E., Josh Willis, Catia M. Domingues, Paul Barker, Neil J. White, Ann Gronell, Ken Ridgway, John A. Church, 2008: Changing Expendable Bathythermograph Fall Rates and Their Impact on Estimates of Thermosteric Sea Level Rise. J. Climate, 21, 5657–5672.
doi: 10.1175/2008JCLI2290.1
http://journals.ametsoc.org/doi/abs/10.1175/2008JCLI2290.1
BBD -
Thanks, and I quite agree that the discrepancy between ARGO and pre-ARGO measurements remains striking. As pointed out in the most recent paper you cited (Lyman et al. Nature 2010), this "raises the possibility of a yet-undiscovered bias in the observing system." It's certainly a possibility that the XBT data are correct, and the ARGO data are biased; we'll have to wait to see. As the ARGO floats were specifically constructed for the purpose of large-scale measurements of OHC, and with the benefit of years of XBT experience, I tend to the belief that the ARGO data are more likely to be correct. By the way, can you shed more light on that Willis estimate of recent OHC rise rate? I realise that you said it's unpublished...
However, I was only citing the Lyman et al. paper to get a representative depth, in an attempt to get MarcusB to elucidate his objection to using the whole-ocean heat capacity. After his comment dismissing the relatively large oceanic heat capacity, relative to the atmospheric, I was left wondering what ocean depth he thought appropriate, which would change the nature of that comparison. Using Jeff's figures, I compute that the top 4m of ocean contains an equal heat capacity to the entire atmosphere. So it seemed to me that although the ocean's temperature will not rise uniformly, the conclusion remains that the ocean is going to absorb far more energy than the atmosphere.
HaroldW
Willis OHC reference:
http://pielkeclimatesci.wordpress.com/2011/02/07/where-is-the-missing-argo-upper-ocean-heat-data/
Apologies - missed that one.
Did MarcusB 'dismiss the relatively large oceanic heat capacity relative to the atmospheric'? Not sure I see this. And he's right to point to thermal stratification with most OHC in the upper ocean layer (~300 - 500m).
I'm not too clear - he was rather terse.
Re ARGO. I am not sure about bias. The disjunction between XBT and ARGO is so great that I wonder if all the calibration problems with ARGO are still not resolved. Remember how it went? First ARGO was too cool (Lyman et al. 2006) then results were withdrawn with apologies for instrument error (Wills et al. 2007). Note how Josh Willis got to be lead author on the latter paper. Ouch.
Perhaps it it now biased warm?
XBT was supposed to be biased cool (eg Wijffels et al. 2008) but perhaps it too is still not correctly calibrated.
Lyman et al. 2010's reconstruction of OHC does not convince. Nor do the rest, and nor will they until that step around 2003 - 2004 is removed.
Sorry - in a rush:
Lyman, J. M., Willis, J. K., and Johnson, G. C. (2006). Recent cooling of the upper ocean. Geophysical Research Letters, 33, L18604.
http://oceans.pmel.noaa.gov/Papers/heat_2006.pdf
Willis, J. K., Lyman, J. M., Johnson, G. C, and Gilson, J. (2007). Correction to “Recent cooling of the upper ocean,” Geophysical Research Letters, 34, L16601.
http://www.pmel.noaa.gov/~lyman/Pdf/heat_2006.pdf
Daft error:
XBT data is considered to be biased warm.
HaroldW, BBD and others,
What's all this about splicing one type of measurement with another?
/sarc off.
When a radical new way of measurement is introduced, it should be run in parallel with the old for at least twenty or thirty years.
We are dealing with multiple chaotic systems here
(I presume that you are all OK with Chaoc theory).
I question that we know all the ins and outs of the old system, let alone the new one.
Cutting the old off and rushing to, what looks to be a superior new system, is not smart.
I realise that you all are now responsible for the data.
But we have to keep in mind, not only the uncertainties, but the unknown, unknowns.
I suspect that the latter are substantial.
Damn!
Anyone want a job of translating my thoughts into writtern English?
For "chaoc" read "chaos".
For " realise that you all are now responsible for the data"
Read " realise that you are NOT responsible for the data"
There is no prize for anybody finding more errors of mine, be they spelling, puncuation, semantics etc.
But I do like "puncuation"
You probably would not guess it, but I do always proof read before pressing the "Create Post" button.
My problem is that I can't help reading for meaning rather than exact content and I know what I have meant to type, so only manage to find about 50% of my mistakes..
But no.
There is no excuse for carelessness.
BBD -
Thanks for the link to the Willis analysis, even if preliminary. The OHC increase is a far cry from the claimed energy imbalance figure. Which of course was one of the primary purposes of the ARGO programme, to measure OHC. I'm looking forward to the published article.
As for MarcusB, I agree with him that the ocean doesn't warm uniformly, especially over the time scale of decades. And Jeff's article says as much. Jeff's point is that a relatively small change in ocean temperature, especially deep where measurements are scarce, represents much more energy than the century-long change in surface air temperature. I read MarcusB's brief post as dismissive of the referenced article -- if I wrongly interpreted his tone, then of course I will apologize.
AusieDan
Unfortunately that is not what has happened. XBT measurements were phased out as ARGO floats became widely distributed across the major basins.
All that now remains is the array of tethered buoys spanning the Equatorial Pacific and Atlantic. They show no trend. The big increase in OHC is coming from ARGO, which is in disagreement with XBT data as well.
If you would like to see this for yourself, you can.
Go to the GODAS data page
http://www.cpc.ncep.noaa.gov/products/GODAS/data_distribution.shtml
Ignore the Temperature Profiles pane. From the Temperature Profiles Numbers pane, pick
Ocean basin - global
Latitude 90S - 90N
Depth - 250m to 500m
And click Submit.
Interesting, isn't it? See how XBT (green curve) and tethered buoy (red curve) data show no trend. Compare with ARGO (blue curve).
As I said earlier, I suspect there is work to be done cleaning up the OHC reconstruction and tightening the error bars on the OHC estimate for the global ocean.
HaroldW
I'm curious about where things are headed. Lyman et al. 2010 (Willis of course among the co-authors) produced a reconstruction that raises questions (and eyebrows).
More of the same this year? Or a firm grasping of the ARGO calibration nettle?
Ocean heat content ties in with ocean level change. For the oceans to expand, in a first and dominant approximation, the total heat content (on average) has to increase. There is no future in calculating possible expansions from subsets of the ocean. Given that the deep oceans have extremely sparse sampling, we have a few simple equations with many inadequate data points.
It's interesting to note - perhaps accelerated by events in Japan - that more blogs are mentioning what is not known about the extent and effect of deep ocean floor heat sources. One of my first climate blogs was about the uncertainty of estimates of heat flow from the crust to the oceans and atmosphere. There are some rather large variations in geothermal gradient and there are active exothermic processes in sedimentary pile formation like Gulf of Mexico. Things like release of water of hydration in early stages of deep burial metamorphism. It's not hard to envisage that certain anomalous events thousands of years ago - if they happened - are only now finding their way to thermometers used to interpret climate.
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