This paper is to be published on-line on Friday in Physics Letters A Dr. Douglas graciously sent me an advance copy, of which I’m printing some excerpts. Douglas and Knox show some correlations between Top-of-atmosphere radiation imbalance and the Pacific Decadal Oscillation (PDO). The authors credit Dr. Roger Pielke Sr. with reviving interest on the subject due to his discussions on using ocean heat content as a metric for climate change.
Abstract
Ocean heat content and Earth’s radiation imbalance
D.H. Douglass and R, S, Knox
Dept. of Physics and Astronomy, University of Rochester, PO Box 270171, Rochester, NY 14627-0171, USA
Earth’s radiation imbalance is determined from ocean heat content data and compared with results of direct measurements. Distinct time intervals of alternating positive and negative values are found: 1960–mid-1970s (−0.15), mid-1970s–2000 (+0.15), 2001–present (−0.2 W/m2), and are consistent with prior reports. These climate shifts limit climate predictability.
Introduction:
A strong connection between Earth’s radiative imbalance and the heat content of the oceans has been known for some time (see, e.g., Peixoto and Oort [1]). The heat content has played an important role in recent discussions of climate change, and Pielke [2] has revived interest in its relationship with radiation. Many previous papers have emphasized the importance of heat content of the ocean, particularly the upper ocean, as a diagnostic for changes in the climate system [3–7]. In this work we analyze recent heat content data sets, compare them with corresponding data on radiative imbalance, and point out certain irregularities that can be associated with climate shifts. In Section 2 the conservation of energy is applied to the climate system and the approximations involved in making the radiationheat content connection are discussed. In Section 3 data sources are enumerated. Section 4 gives the radiation imbalance for the Earth’s climate system. In Section 5, climate shifts, radiative imbalances and other climate parameters are discussed. A summary is in Section 6.
Discussion:
…
What is the cause of these climate shifts? We suggest that the low frequency component of the Pacific Decade Oscillation (PDO) may be involved. The PDO index changes from positive to negative near 1960; it remains negative until the mid-1970s where it
becomes positive; then it becomes negative again at about 2000. This mimics the FTOA data. The PDO index is one of the inputs in the synchronization analysis of Swanson and Tsonis [43]. One would like to be able to predict future climate. Such predictions are based upon the present initial conditions and some expectation that changes in the climate state are continuous. However, if there are abrupt changes such as reported by Swanson and Tsonis then this is not possible. These abrupt changes presumably
occur because the existing state is no longer stable and there is a transition to a new stable state.
Summary:
We determine Earth’s radiation imbalance by analyzing three recent independent observational ocean heat content determinations for the period 1950 to 2008 and compare the results with direct measurements by satellites. A large annual term is found in both the implied radiation imbalance and the direct measurements. Its magnitude and phase confirm earlier observations that delivery of the energy to the ocean is rapid, thus eliminating the possibility of long time constants associated with the bulk of the heat transferred. Longer-term averages of the observed imbalance are not only many-fold smaller than theoretically derived values, but also oscillate in sign. These facts are not found among the theoretical
predictions.
Three distinct time intervals of alternating positive and negative imbalance are found: 1960 to the mid 1970s, the mid 1970s to
2000 and 2001 to present. The respective mean values of radiation imbalance are −0.15, +0.15, and −0.2 to −0.3. These observations are consistent with the occurrence of climate shifts at 1960, the mid-1970s, and early 2001 identified by Swanson and Tsonis. Knowledge of the complex atmospheric-ocean physical processes is not involved or required in making these findings. Global surface temperatures as a function of time are also not required to be known.
Tallbloke, I don’t think you had any trouble understanding my last statement. You replied that you don’t have time to run down the studies on other attributing factors to rising sea level. This appears to be the same solution those attributing sea levels for the IPCC came to.
steve (03:32:01) :
Tallbloke, I don’t think you had any trouble understanding my last statement. You replied that you don’t have time to run down the studies on other attributing factors to rising sea level. This appears to be the same solution those attributing sea levels for the IPCC came to.
Steve, on re-reading it, I had no trouble. Apologies for my initial confusion.
Maybe the IPCC decided that given the evidence for the other factors they had identified, your author’s had overstated their case. Without ploughing through the IPCC references, we don’t know. I don’t have the time. Do you?
It’s called weighing the balance of evidence.
Steve,
here’s the abstract of your paper. I note they say their study accounts for all variation in sea level rise. Not that it accounts for all sea level rise.
Also, it was published in 2008 as you originally noted, well after the last IPCC report. Glad I didn’t start ploughing through that pile of *snip* again. 😉
Anyway, I’m not sure I fully agree with them, because the swell and fall associated with the ’98 el nino looks pretty obvious to me, but without reading the full paper, I don’t know what smoothing techniques they’ve applied, or what other factors they removed from the curve before matching their data to the residuals. Also, how would they explain the recent fall in rise rate, which is equivalent to a lot of three gorge projects?
Impact of Artificial Reservoir Water Impoundment on Global Sea Level
B. F. Chao,* Y. H. Wu, Y. S. Li
By reconstructing the history of water impoundment in the world’s artificial reservoirs, we show that a total of ~10,800 cubic kilometers of water has been impounded on land to date, reducing the magnitude of global sea level (GSL) rise by –30.0 millimeters, at an average rate of –0.55 millimeters per year during the past half century. This demands a considerably larger contribution to GSL rise from other (natural and anthropogenic) causes than otherwise required. The reconstructed GSL history, accounting for the impact of reservoirs by adding back the impounded water volume, shows an essentially constant rate of rise at +2.46 millimeters per year over at least the past 80 years. This value is contrary to the conventional view of apparently variable GSL rise, which is based on face values of observation.
Steve, one more thing. Their study agrees well with my model, which shows a pretty steady rise in ocean heat content from 1920 to 2003, as derived from my method for cumulatively counting sunspots by consecutively adding and subtracting their magnitudes above and below the ocean equilibrium value I have determined, and factoring in changes in LOD.
http://i630.photobucket.com/albums/uu21/stroller-2009/temp-hist-80.gif
Leif,
you wrote “It is very simple: in climate studies [page 2, line 4 of the paper] “one generally finds the total ocean heat content expressed in units of 10^22 J””.
In actual fact, it is the CHANGE in heat content dQ that they are expressing. When we say the ocean has a heat content we are obliged to ask “in relation to what?” It is the same as saying a stone has a potential energy. We would say it has a potential energy in comparison to the earths surface (if the stone was aloft) or perhaps we would be comparing it to the height from a table to the floor in our living room.
Similiarly ocean heat content is devoid of meaning in absolute terms. Climate science is saying something like “if ocean temps increase at x degrees/decade then there must have been a quantity of heat Q joules/decade to cause that to happen. They can then compare this to the assumed radiative imbalance in watts/m2. It follows that z watts/m2 over a period of time is equivalent to a quantity of joules. This should agree with common sense.
There is also a climate change effect from this. Imagine a hypothetical situation in which the ocean and the air were at the same temperature. No heat could therefore flow from the ocean to the air. Let there now be a radiative imbalance that adds a quanity Q joules causing ocean temps to rise. There now would exist a temperature gradient that allows heat to flow from the ocean to the air.
At risk of repetition I will say again: absolute ocean heat has no meaning. It is the difference between these two points in time that is relevant to climate studies because it implies a radiative imbalance. Ocean heat content has meaning only when compared to something having a different temperature. And even then it is only the DIFFERENCE in temperature that is important. For example, it matters not a jot whether 2 bodies in contact have temperatures of 100 degrees and 200 degrees respectively or 1100 and 1200 degrees. The SAME amount of work will be extracted. The SAME amount of energy will flow.
Tallbloke, let me ask one simple question. If 750-800 km3* of groundwater is extracted each year per Konikow and Kendy Hydrogeology Journal Vol 13 NO1 March 2005, then where is the study that shows an inconsequential percentage of this very large amount makes it’s way to the ocean? I don’t mean to keep harping on this topic but it seems to me outlandish to declare we can determine ocean heat content by sea level rise when we have so little available information on what actually attributes to the rise in sea level. I will drop this now. I think I have made my point that if anything deserves skepticism then this issue definately does.
tallbloke (00:43:51) :
A reasonable point of view.
The fact that the energy gets there is the part we DO know. The uncertainty comes with WHAT MECHANISMS provide the diapyncal mixing for the energy to gets there.
tallbloke (01:15:28) :
It seems that you already answered your own question above.
Leif Svalgaard (00:04:27) :
Since this meme doesn’t seem to be dissipating, I’ll give it a try.
I’d guess that some other transfer of energy (other than classical “heating”) is occurring and breaking into heat in the corona. What’s your opinion?
steve (05:21:07) :
it seems to me outlandish to declare we can determine ocean heat content by sea level rise when we have so little available information on what actually attributes to the rise in sea level. I will drop this now. I think I have made my point that if anything deserves skepticism then this issue definately does.
Steve, I agree there is much uncertainty. You are right to raise these issues. I have created a way of looking at this stuff which doesn’t rely on absolute quantities we are not sure of. i.e. ocean heat content. My model works by comparing relative values and by scale and proportion. It can accommodate updated figures. I think this is a reasonable way to work towards a better understanding of how it all fits together. What I do know is that my calcs on OHC fit with the observed rise in SST’s and the dropoff of temp to the thermocline. In short, I’m fairly confident I’m on the ballpark.
Thanks for the heads up on the issues you have raised.
oms (06:12:34) :
tallbloke (00:43:51) :
So I went and asked an oceanologist how the received energy is propogated downwards. He told me that below the depth waves mix the water to (50 metres in the tropics, deeper in the southern ocean where the rollers are really big), tidal action and current subduction does the job.
A reasonable point of view.
tallbloke (01:15:28) :
Can you see a way any of those three might be able to transfer energy downwards to depths of 700m or more, well beyond the 70m or so that is the limit of where the transfer of energy from incoming solar radiation …
It seems that you already answered your own question above.
Well, someone else answered my question, James Annan actually, a noted AGW scientist. But I want a second opinion and maybe another theory from a physicist because the late Bob Sterling said modelers (like Annan) love to posit subducting warm currents to help their models along, but he’d never found one in 30 years of roaming the oceans taking measurements…
But it has to get down there somehow….
It’s a good puzzle.
🙂
“here’s the abstract of your paper. I note they say their study accounts for all variation in sea level rise. Not that it accounts for all sea level rise.”
Yes, I’m not sure if you are saying this as a point or to correct me. If it is to correct me I would have you note I stated sea level rise variations.
I will take some time and look at what you have done. I do think you should consider the variables I have pointed out and acknowledge that the amounts of water involved cannot be justifiably ignored.
Sandy (18:44:59) :
“Sea water which has an average salinity of around 3.5% exhibits NO maximum density before it freezes; for salinity of 2.47% or higher; where it freezes somewhere around -2.5 degC.”
Hmm if seawater density continued going up all the way to freezing then at the bottom of the ocean pressure alone would cause freezing. Salinity might lower the temp. at which density is at a minimum but the minimum must be there or the oceans would be solid at a few hundred feet.
No, look at the phase diagram of water, water has an anomalous property that its solidus slopes towards lower temperature at higher pressure, that is why water doesn’t freeze at the bottom of the ocean it has nothing to do with a maximum (sic) density. The first poster is correct sea water has a maximum density at its freezing point.
http://www.its.caltech.edu/~atomic/snowcrystals/ice/h2ophase.gif
Tallbloke thanks for the conversation. I see that you agree there are uncertainties that have not been properly addressed and that is all I really wanted. Good luck with your work on SSTs and sunspots. I am not sure what mechanism you are relying on to provide the increase in SSTs but the correlation does look impressive.
Leif Svalgaard (00:02:02) :
Nasif Nahle (23:12:35) :
The units of specific heat capacity are J/Kg K.
No, all that is required is a way of removing the reference to the ’size’ of the body, be it measured in kg or m^3 or moles or whatever. To make the difference between an extensive and an intrinsic property.
No? Then tell me: what the units of specific heat capacity (Cp) are? Again, Leif… The units of heat are watts, that is Joules/second (J/s) because it is energy in transit. The units of energy are Watts*second (W*s) or Joules (J). Q is heat, i.e. energy in transit. You’re again confounding units and concepts, I don’t know with which purpose.
Read the basics from Wikipedia, given that you like it in extreme:
http://en.wikipedia.org/wiki/Units_of_energy
http://en.wikipedia.org/wiki/Watt
http://wiki.answers.com/Q/How_many_watts_in_a_joule
And I gift you this example:
Q (heat) = m (Cp) (ΔT/Δt)
Q (heat) = 0.000157 Kg (871 J/Kg * K) (1.23 K/60 s) = 0.0028 J/s = 0.0028 W
See the units?
The heat content has nothing to do with ‘available’ energy [it is in fact not available once it is heat – entropy never decreases] and has nothing to do with gravitational potential energy. And the oceans have a certain heat capacity [ability to store heat], determined by their volume [or at least the volume considered].
Of course not! Except for the amount of energy in transit which is absorbed by the system and becomes a portion of the available energy.
As I have tell you many times, heat is not gravitational potential energy, neither kinetic energy, neither internal energy; it is Energy in transit and stops being heat immediately it is absorbed by a system.
There is really no need to bring in all these straw men [like ‘heat is photons’ and the unit of heat [dQ] is Watt while that of Q is Joule, etc]. It is very simple: in climate studies [page 2, line 4 of the paper] “one generally finds the total ocean heat content expressed in units of 10^22 J”
What a confusion of the authors, uh? They are messing internal energy with heat. 🙂
In http://www.climatesci.org/publications/pdf/R-247.pdf you can find an authoritative [you like authorities] discussion of the issues of heat storage, H, in the oceans. The quantity dH/dt is a measure of ‘Global Warming’, which makes H(t), the heat stored in the system at any given time, t, a very interesting and important number.
Heat, a process, cannot be stored. Energy is stored. As I have told you many times, AGWers tend to confound scientific concepts, laws, theories, etc., and it is not a matter of jargon. Could you store photosynthesis or cell respiration? Now that you have introduced Enthalpy into this discussion, would you like to expand on this topic?
Leif Svalgaard (01:10:25) :
Nasif Nahle (23:28:37) :
Sorry for them (the authors of the paper);
You can feel sorry for The National Research Council too: http://www.nap.edu/openbook.php?record_id=11175&page=21
and for every other climatologist out there.
This is accepted usage and is therefore correct, the way language evolves. This is really my only point.
Solipsism? As I have said, climatology and probably solar physics are creating this confusion. Ask a physicist!
It is not my fault the ignorance of the NRC on physics issues; it’s not my fault the NRC neglects the correct, clean, unpolluted science.
tallbloke (02:33:44) :
Leif, I think you are both right. But as an example of the way such idiomatic use as you propose can lead to incorrect thinking which can pervade an entire branch of science I offer this…
It is not about being right or wrong. It is about what the accepted and used term is in climate studies, In order to communicate one must use the accepted terminology [e.g. the one used by the National Research Council], which is used by everybody, and is not what ‘I propose’. I just go along so I can understand what they are talking about.
Vincent (05:02:22) :
Similiarly ocean heat content is devoid of meaning in absolute terms.
Absolutely not. It is very well determined. The ‘total energy content’ is what is undefined for the reasons you describe. The ‘heat content’ is the amount of kinetic energy in the random, chaotic movements of the molecules, and that is a quantity that can be determined locally simply by inspection of the medium, e.g. by measuring the sound speed or the temperature. The speeds are in relation to the bulk of the medium. That the medium is hurtling through space at enormous speeds [Earth moves at 30 km/s around the Sun] is immaterial. The heat content is a local and absolute quantity. I can in the laboratory cool something to VERY close to absolute zero, so its heat content becomes effectively zero. Heat content is not a ‘relative’ thing.
Nasif Nahle (08:12:26) :
climatology and probably solar physics are creating this confusion. Ask a physicist!
There is no confusion. Very early on, I sent you a quote from Leonard Susskind. Google him. He is a physicist, one of the best: http://en.wikipedia.org/wiki/Leonard_Susskind
Leif Svalgaard (08:43:23) :
tallbloke (02:33:44) :
Leif, I think you are both right. But as an example of the way such idiomatic use as you propose can lead to incorrect thinking which can pervade an entire branch of science I offer this…
It is not about being right or wrong. It is about what the accepted and used term is in climate studies, In order to communicate one must use the accepted terminology [e.g. the one used by the National Research Council], which is used by everybody, and is not what ‘I propose’. I just go along so I can understand what they are talking about.
It is about physical theories and laws, Leif. Climatology is a factual science and it is WRONG some climatologists are using false, unclear and imprecise terminology. The matter is not “accepted terminology”; it’s not a matter of “jargon”, it’s a matter of theories. You and your “climatologists” are leaving out from the field of CLEAN physics.
Leif Svalgaard (08:43:23) :
Vincent (05:02:22) :
Similiarly ocean heat content is devoid of meaning in absolute terms.
Absolutely not. It is very well determined. The ‘total energy content’ is what is undefined for the reasons you describe. The ‘heat content’ is the amount of kinetic energy in the random, chaotic movements of the molecules, and that is a quantity that can be determined locally simply by inspection of the medium, e.g. by measuring the sound speed or the temperature. The speeds are in relation to the bulk of the medium. That the medium is hurtling through space at enormous speeds [Earth moves at 30 km/s around the Sun] is immaterial. The heat content is a local and absolute quantity. I can in the laboratory cool something to VERY close to absolute zero, so its heat content becomes effectively zero. Heat content is not a ‘relative’ thing.
Leif, you’re sinking again in your own ignorance about thermodynamics. Show me from any book or Wikipedia, if you would prefer it, that internal energy and total available content of energy are undefined. If it was so, what the purpose of thermodynamics would be? It is not well defined only for people who don’t understand thermodynamics.
Heat is also well defined, it is the energy in transit transferred from a system to another system, that is why its units includes time, i.e. J/SECOND.
Once again, “heat content” is a void term. Any system cannot contain process quatities.
Sorry for not being specific. Not all climatologists are using false, unclear and imprecise terminology. Most of them understand that heat cannot be stored or contained, even in an assumed “void” solar corona. There is plasma in the corona, i.e. charged particles.
oms (06:17:10) :
I’d guess that some other transfer of energy (other than classical “heating”) is occurring and breaking into heat in the corona. What’s your opinion?
There is no transfer of heat. There is generation of heat. In the solar core there is also generation of heat [by a different process, though]. Even you can generate heat at will: rub your hands together, or strike a match.
In none of these cases is there a transfer of heat from a warmer to a colder body. So, to restrict the usage of the word ‘heat’ to that situation is not very useful. What happens is that you convert one form of energy [mechanical, chemical, potential, nuclear, electromagnetic, etc] into heat [the kinetic energy of random, chaotic motions of the molecules], resulting in a rise of temperature in the medium. This heat is stored in the body until you expose the body to a colder environment at which point some of the heat can be transferred to the colder body, resulting in cooling.
steve (07:52:42) :
I do think you should consider the variables I have pointed out and acknowledge that the amounts of water involved cannot be justifiably ignored.
I don’t think I am ignoring them. My calcs concern what water there was estimated to be in the oceans between 1993-2003, how much sea level rose in that time, an estimate of how much of that was due to thermal expansion, and the amount of solar energy needed to be retained to do that.
The question of exactly how much was kept out by new dams, how much went in through draining of wetlands and loss of trees etc I’ll have to leave to the bean counters. The authors of your paper say new dams have withheld 10,800km^3 of water on land to date. Unfortunately in the abstract, they don’t say from what date. If we take the worst case scenario and assume they mean reservoirs built in the last 80 years and no other process compensated for it, then my study will have missed 1,300 of sea level rise which would have happened in addition to the 10,800 measured rise 1993-2003. The amount of rise due to thermal expansion is around 50% of the total according to the IPCC but if that is based on the residual after other factors are taken into consideration, and we assume the IPCC forgot new reservoirs, then it’ll be a bit more – I think. (It’s a bit of a braintwister)
So we are left with me needing to account for the energy required to heat the oceans enough to increase in volume by 6050Km^3 rather than 5400Km^3. So I may have understimated the rise in ocean heat content 1993-2003 by around 10%, the overall result being uncertain by a margin of, at a guess, 15%
I’m not a stickler for exact quantities, except when the barman is topping up my pint, so I can live with that.
Cheers, and thanks again for keeping me aware of uncertainty.
Nasif Nahle (09:12:51) :
Show me from any book or Wikipedia, if you would prefer it, that internal energy and total available content of energy are undefined.
Vincent was talking about ‘total energy content’, not your ‘total available energy’. The ‘internal energy’ is also a bit undefined: does it include nuclear binding energy, for instance’. What you mean is ‘thermal energy’ also known as ‘heat’ which is the kinetic energy of the random, disorganized motion of the molecules measured by the temperature of the body. And, of course, ‘thermal energy’ or ‘heat’ is not available to do work. Once an energy form has turned into heat it is no longer ‘available’. To make it do work you need to connect it to another reservoir with a lower temperature and it it this other reservoir and its temperature that determine the amount of work you can get done.
Leif Svalgaard (09:20:38) :
There is no transfer of heat. There is generation of heat. In the solar core there is also generation of heat [by a different process, though]. Even you can generate heat at will: rub your hands together, or strike a match.
In none of these cases is there a transfer of heat from a warmer to a colder body. So, to restrict the usage of the word ‘heat’ to that situation is not very useful. What happens is that you convert one form of energy [mechanical, chemical, potential, nuclear, electromagnetic, etc] into heat [the kinetic energy of random, chaotic motions of the molecules], resulting in a rise of temperature in the medium. This heat is stored in the body until you expose the body to a colder environment at which point some of the heat can be transferred to the colder body, resulting in cooling.
Absolutely nonsense.
Nasif:
Please, pretty please, would you have a go at my question ?
You seem to be saying that once the solar energy is absorbed into the ocean, it is no longer ‘heat’ but part of the overall ocean energy, and must be accounted for in either the gravitational potential, the internal energy, or the kinetic energy.
Can you see a way any of those three might be able to transfer energy downwards to depths of 700m or more, well beyond the 70m or so that is the limit of where the transfer of energy from incoming solar radiation to the water molecules and metallic ions and chloride ions takes place? For example, could gravity differentiate those molecules or ions which have absorbed more solar energy from those which have absorbed less?
You might have a look at the quote from the site about the change in bond lengths and hydrogen atom angle too.
Thanks for your help.