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.
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Stephen Wilde (02:09:19) : Thus the air as a whole acts as a negative feedback neutralising variations in the rate of energy release from the oceans.
Agreed. Maybe if there were no trade winds or currents, the oceans would get more warmth further down. But the warmth at the surface is drawn away by circulation.
wattsupwiththat (00:00:58) :
“The question hinges on rates of uptake vs outlet. I certainly don’t think that the oceans act as a very long period capacitor, but they do have capacity” —
”
Since the ARGO network has been operating we have not seen much change in average surface temps of the Ocean. Nor have we seen much change in the Deep Ocean Temp, although we dont have any reliable long term records.
One of the reasons there has not been much publicity about ARGO results is probably because it hasn’t produced the expected results as modeled by the IPCC, which encouraged the UN to establish the network in the first place.
can we conclude that the system is in a balanced situation.
Its one thing to heat a pot of water from the bottom and boil it in 5 minutes try boiling it by holding the element over the top and give a similar radient temp as the sun say 1400 w/sq m and see how hot the water gets. The absorption time seems to be the the same as the release time. It’s an interesting experiment, change the depth of water in the saucepan and observe. Model the ocean in a saucepan : probably give you better results than some of the IPCC models !!
By my back of the envelope calculation the average ocean Temp is not much more that 6 deg. C. (90% of the ocean is deep ocean with temp of about 4.5 to 5 Deg.C) insulated by a few km of rock and mantle from the planet core with temps of several 1000 deg. What will be the convectional transfer from the planet core to the oceans. It must be very small.
If the oceans are ‘storing heat” in the tropics as a net gain from the day /night radiative balance then it will be transported by currents to a midlatitude where the balance is negative wit ocean currents at say 2 to 4 knots it will only take 2 or 3 months for the stored heat to reach those latitudes.
If the Oceans were storing heat we would have seen signs of it by now.
Im much more impressed by the recent post on the natural regulator function of the tropical storm belt.
I should make it clear as to why the effect of the air on the oceans is always a negative feedback.
If the oceans release energy faster then the changes in the air accelerate it’s removal to space thus limiting the warming of the air.
If the oceans release energy more slowly then the changes in the air seek to pull more energy from the oceans thus limiting the cooling of the air.
The flow is always sun to oceans to air to space. It cannot be reversed. Only the speed can be changed.
The systems in the air can only push energy into space or pull it from the oceans. They cannot pull energy from space or push it into the oceans.
All this is explained in tiresome detail in my collection of articles at climaterealists.com for anyone who has the patience.
The relevance to CO2 is that the same mechanism neutralises the warming effect of all increases in GHGs whether from more CO2, water vapour or anything else.
Dr. Douglas: Newman et al (2003)…
http://www.cdc.noaa.gov/people/gilbert.p.compo/Newmanetal2003.pdf
…and Zhang et al (1997), who were the first to calculate the PDO…
http://www.atmos.washington.edu/~david/zwb1997.pdf
…determined that the PDO was a lagged effect of ENSO. It then seems as though you’re arguing indirectly that ENSO and TOA radiation imbalance correlate and that the low frequency component of ENSO caused the climate shifts. Both make sense, but let’s look at the latter.
You wrote, “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.”
Smoothed NINO3.4 SST anomalies indicate that the frequency and magnitude of El Nino and La Nina events vary and that the positive and negative phases of ENSO have the same time periods that you described:
http://i31.tinypic.com/bezz8h.jpg
The use of ENSO in a discussion of OHC makes much more sense to me. During an El Nino, the eastern tropical Pacific discharges heat from the ocean to the atmosphere, and during the La Nina, the eastern tropical Pacific recharges the ocean heat by absorbing heat from the atmosphere. Tropical TLT anomalies and NINO3.4 SST anomalies correlate quite well, as could be expected:
http://i43.tinypic.com/2isid84.jpg
However, during the El Nino phase, Pavlakis et al (2008)…
http://www.atmos-chem-phys-discuss.net/8/6697/2008/acpd-8-6697-2008-print.pdf
…illustrated that downwelling shortwave radiation (and for the tropical Pacific it’s “the component of the net heat into the ocean with the largest magnitude”) increases over the Pacific Warm Pool, and the increase in DSR is significant, 25 watts/sq meter during the 1997/98 El Nino.
http://i41.tinypic.com/2435kbb.jpg
That leads me to this thought. Although it may seem counterintuitive, I’m presently bouncing around the idea that El Nino events may actually result in an increase in OHC. And if the frequency and magnitude of El Nino events exceed the frequency and magnitude of La Nina events, which they have since 1976, OHC will rise, which it has. During the 50s through mid-70s, the frequency and magnitude of La Nina events exceeded the frequency and magnitude of El Nino events, and OHC declined.
I’ll write that up as a post in the next few days and see what the feedback is. I suspect that many will disagree.
Stephen Wilde: You wrote, “The solar input varies over century timescales, the rate of energy release from ocean to air varies over multidecadal timescales with the PDO as the largest component.”
Two things: On whose TSI data are you basing the assumption that “solar input varies over century timescales?” Are you still using Lean at al?
Second, the PDO does not reflect SST or OHC. It reflects the PATTERN of SST anomalies for only the North Pacific, north of 20N. It’s ENSO that discharges and recharges OHC, not the PDO.
Guess this reinforces we need to prepare for the cold ahead. As the sun hits another lengthy spotless streak the signs couldnt be clearer. Sitting in the sun here in Australia today – it used to make you hot, now its simply tepid if that. As the poles are on a growing trend again I guess this means if this speeds up Tasmania will become part of the mainland again and so will Papua New Guinea
Lindsay H. (03:50:00) :
can we conclude that the system is in a balanced situation.
Not really. We may be at the peak of a long term cycle, and the downslope of ocean heat content is slow at the moment, but it’s there. Josh WIllis, the cheif ARGO data specialist, admitted to an online magazine that there had been a “slight cooling” since 2003. He later recanted that in a NASA article by saying it was level. I wonder why. It should be noted that his original comment was made *after* the ‘correction’ of the data which showed a steeper decline.
Its one thing to heat a pot of water from the bottom and boil it in 5 minutes try boiling it by holding the element over the top and give a similar radient temp as the sun say 1400 w/sq m and see how hot the water gets.
And don’t forget to introduce surface mixing by wave action, and deeper mixing by tidal action. I love kitchen corner experiments, but you have to simulate all important and relevant contributing factors to get a meaningful result.
If the Oceans were storing heat we would have seen signs of it by now.
We have. The satellite altimetry of sea levels is evidence of it. The sea level has risen substantially due to thermal expansion since 1993 when accurate satellite measurements began. It has slowed down since the sun went quieter in 2005.
Stephen Wilde (03:22:31) :
Over time the oceans slow down or accelerate that transmission of energy for reasons not yet determined. In that process the ocean temperatures rise and fall slightly and the rate of energy transfer to the air varies up and down slightly.
Excellent analysis as always.
I suspect the rate of transmission is affected by the overall switching between modes of energy absorption, and modes of energy release. These take place at all timescales:
Diurnal modes affecting near surface waters due to difference in air temp between night and day.
Seasonal modes due to varying insolation. This will average across the globe, but is an important effect on an annual northern/southern hemisphere basis.
Decadal modes, depending on the state of the solar cycle. The peak to trough effect of the sun on ocean heat is masked by the fact that the el nino events are stronger near solar minimum. They are the manifestation of the ocean going into heat release mode following the strong absorption of heat to deeper levels during the height of the solar cycle. This is why the apparent signal in the temperature record is only 0.15C or so.
Multidecadal modes. These are due to runs of high or low solar cycles. My calcs show the heat is stored to at least 700 meteres, probably much more in places. My supporting evidence, apart from my calcs on thermal expansion (verified by Leif Svalgaard), is that the average temperature increase of the top 700m of ocean would be 0.15C from 1993 to 2003 for the energy retention I calculated. This is consistent with a surface increase of 0.3C (observed) and a roughly linear reduction of temperature to the thermocline of the ocean from the surface. (Also observed).
Century modes. The 10be record shows that solar variation can occur on long time scales. There is a point of balance with insolation at which the oceans neither gain nor lose heat in the longer term. My model suggest the oceans were pretty stable heat content wise from 1850 to 1935, notwithstanding the 30 year up’s and downs helped along by the variation in solar cycle amplitudes. Since then, they warmed strongly, leading to the sea level rise we have winessed.
Whoever told you that, Leif, weren’t all there.
Leif Svalgaard (23:13:44) :
I have just [in another thread] been lectured that the oceans contains no heat, as heat cannot be stored, so what is this whole paper about?
REPLY: Gosh Leif, I dunno. How’d that happen? Oceans = OBAHFC (One Big Assed Heat Flux Capacitor) 😉 – A
A somewhat pedantic point of physicists is that one refers to heat as energy during transfer only. If one looks at the oceans as being at a “dead state” temperature, then one does not see the oceans as a source, but rather only as a sink. In another context one must see the oceans as a source and the polar regions as a sink, howeve. I’d like to know, Leif, what was the context of this other thread?
KimW @00:21:09, that is at the surface; go deeper and the temeprature varies less. The thermoclines move down in the Summer and retreat in the winter.
@Lindsay H. (03:50:00) :
While there has been progress in describing decadal variability in temperature trends, there is always that pesky centennial temperature rise of ~ 0.6 degrees per century which has been with us since the Maunder Minimum. That’s the one I find interesting. Could it have anything to do with cold, deep ocean water being replenished during Grand Minima then slowly mixing with surface water?
I have thoght for a long time that part of the seeming chaos of climate occurs because there are many feedback loops with extremely different characteristic times. In this paper the authors argue for a short characteristic time in ocean heat transfer; but we know for certain that the “overturning” time of the oceans must be thousands of years. By overturning I mean the process in which bottom water is created in polar regions, sinks, and eventually returns to the surface in much lower latitudes. How much energy can one store in this loop? Well, bottom water might vary by only a few degrees C at present, but we are talking about enormous volumes of water, so the energy stored might be significant. On the other hand ocean surface currents, and internal waves, have characteristic times of a few years to perhaps a decade at most. So here are two loops with very different characteristic times. BY the way, the long period loop here also has some impact on CO2 because bottom water, when returning to the surface, warms, expels CO2, and precipitates calcite.
Leif Svalgaard (23:13:44) : REPLY: Gosh Leif, I dunno. How’d that happen? Oceans = OBAHFC (One Big Assed Heat Flux Capacitor) 😉 – A
No wonder that the ocean can store heat – its just shifted to a different time frame!
wiki: “The flux capacitor, which consisted of a regularly squared compartment with three flashing lights arranged as a “Y”, was described by Doc as “what makes time travel possible”. “
The oceans are not well mixed. They have many layers that differ in temperature and salinity with sharp transitions between layers. Submariners and whales use these channels to listen and send sounds over thousands of miles. It’s quite conceivable that heat would be trapped in one or more of these layers and persist there for long periods of time. Since the top 15 m of the ocean contains as much heat as the entire atmosphere, a layer doesn’t have to be very thick to have a significant effect on the temperature of the atmosphere should it suddenly enter a “pipeline” to the surface where it could dump its heat.
I find it interesting that anyone believes they can prove the oceans are warming based on sea level rise. How much of the sea level rise is based on new dam construction? According to the paper by Chao, Wu and Li in Science 11 apr 08 virtually all the variations in sea level rise can be attributed to land sequestration.
Then there is the matter of biomass. How much water is released to the system by deforestation? First you have the water in the vegetation to take into account, typically 60-80% water by weight. Then you have the fact that trees are replaced by grasses which reduces the depth that water can soak into the soil. During the deforestation you also have soil erosion that flows to the bottoms of lakes and rivers decreasing their holding capicity.
Then there is land use issues. Draining of swamps for construction. The use of ground water. The Ogallala aquifer system has had water level decline by as much as 75 feet in some areas since the 1950s. Some areas have had a 30 feet decline in just the ten years from 1996 – 2006. This is just one aquifer system in the world of hundreds? thousands?
Once we have a handle on how much water is being added/subtracted from the system then how will we measure the sea level rise? Tide gauges or satellites? Tide gauges will require a firm handle on tectonic plate movements and land rising/falling. There seems to be some indication that depletion of ground water causes a change in the rate of rising/falling so there is reason to doubt this has remained constant. Satellites then? Is the Earth contracting or expanding and why? This would seem important if you are going to measure from the center of it to determine sea levels. Shen, Chen and Li in the AGU fall meeting stated the Earth is expanding at the rate of about 0.6mm per year for the last ten years. Is this a constant rate? does it always expand or does it also contract?
Once you have solved all these issues and want to determine the temperature of the oceans by thermal expansion equations then you can probably get a good idea of ocean heat content. Until then my view is it would be a better idea to get out your thermometer.
I am not quibling with the main conclusions of this paper but in a
2008 Melbourne presentation:
http://www.lavoisier.com.au/articles/greenhouse-science/solar-cycles/IanwilsonForum2008.pdf
I have already shown that abrupt long-term changes in the Earth’s rotation rate precede abrupt changes in the PDO, from positive to negative and vice versa, by roughly six year (see slide 28 of 44). I have also shown that these abrupt changes in the Earth’s rotation rate closley match abrupt changes in the motion of the Sun about the Solar System’s Barycentre (see slide 37 of 44). hence, I have no problem predicting the approximate date of the next change in the PDO (to positive). It will occur around ~ 2018 (=/- a few years
either side).
Hence, the following quote from this paper about the unpredictability of the flips in the PDO is completely false.
quote:
“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.”
No they actually occur because of long-term changes in the Earth’s rotation rate, that are being driven from outside the Earth. Why are most of you ignoring this fundamental result?
These results are now published in a compendium of papers in Russian and are available (In English) from me upon request.
Correction – that should have read ~ 2014 – 2018 (+/- a few years), Sorry.
I’ve seen little discussion or estimates of the amount of energy that gets converted into work (the Physics 101 definition), rather than just being input and then exhausted from the earth climate system.
I refer to the considerable horsepower that goes into making the oceans or the atmosphere circulate, or the storage of that energy chemically in a giant redwood or an acre of corn. Snow landing on a glacier stores potential energy that is released slowly over decades.
This conversion to kinetic and chemical energy doesn’t show up on any thermostat, and I’m unaware that it’s a component in any climate model, yet it’s there and it has to be a huge amount.
This may not be the secret hidden heat sink that some modelers seek, but it’s surely a part of it, and can’t continue to be ignored.
steve (06:17:22) :
I find it interesting that anyone believes they can prove the oceans are warming based on sea level rise. How much of the sea level rise is based on new dam construction? According to the paper by Chao, Wu and Li in Science 11 apr 08 virtually all the variations in sea level rise can be attributed to land sequestration.
Just togive some relative sense of scale, the Three gorges dam is around 30 cubic km once filled. The thermal expansion of the oceans is around 5400 cubic km and that’s just 1993-2003.
The IPCC bases it’s estimate of the proportion of sea level rise due to thermal expansion on estimates of the meltoff (mainly from Greenland and Antarctic peninsula, plus various glaciers), the land use factors you have pointed out, and isostatic rebound, all subtracted from the total rise.
If you disagree with them, fair enough, they have some other stuff wrong too as we know. However, you have to start somewhere, and ‘sticking in the thermometer’ isn’t infallible either, as Anthony, Josh Willis and others have discovered.
I have weighed the balance of evidence through moderately extensive study, and reached my own judgement. The model I have built from that seems to tie together several strands concerning SST, ocean heat content, changing sunspot counts, changes in length of day, the PDO and AMO, changing incoming shortwave and outgoing longwave radiation, and some other stuff.
If you can do better with your thermometer, get cracking and feed us the data.
I have to ask a stupid question and I don’t have much time to think it out. Sorry. Why do we talk about heat “stored in the ocean” rather than heated (ocean) water (vast amounts) being moved around (and up and down) by both ocean and air currents?
It is the concept of “stored warmth” that bothers me. “Greenhouse” suggests “stored warmth” because of “that man-made carbon-kryptonite space shield” (thanks, dario). Bear with me as I check a text. If anything is stored in the ocean, it seems to me it should be cold, dense, salty water created by the freezing at the poles. The colder the water, the denser (gravity pulls it downward); the more saline the water, the lower the freezing point. “The seafloor under ice is the coldest, saltiest water around”, which leads to the seasonal thermocline (halocline, pynocline, nutricline) and beyond that the permanent thermocline. “A force must be applied to move a dense medium upward into a less dense medium.” The forces are gravity, tides, especially with mid-ocean ridges and sea mounts, and wind-driven currents. Even though this paper talks about a top-of-atmosphere flux indicating regime change in earth’s temperature, does any of this lead toward understanding changes in the “stored cold”.?
“At least three times in earth’s history the bottom waters of the ocean have been considerably warmer than they are today.”
I continue to abhor the idea of Greenhouse. No one who thinks of a Greenhouse can possibly, at the same time with the active neural network (this is very important), think of “radiation imbalance”. The latter is the concept about which scientists and non-scientists alike must educate the populace if we are to have any hope of stopping the CO2 kryptonite space shield nonsense.
par5, The Great lakes are always 4C at the bottom. At the surface, it gets warm in the summer and obviously freezes in the winter. The thermocline descends, at least in Eastern Lake Ontario, to about 70-80 feet. If the year was longer then, the thermocline would have longer to descend. However, it isn’t so that 90 feet, the temperature enver changes.
This does, however, give some idea of how the oceans heat.
Lindsay H. (03:50:00) :
…Its one thing to heat a pot of water from the bottom and boil it in 5 minutes try boiling it by holding the element over the top and give a similar radient temp as the sun say 1400 w/sq m and see how hot the water gets. The absorption time seems to be the the same as the release time…
…By my back of the envelope calculation the average ocean Temp is not much more that 6 deg. C. (90% of the ocean is deep ocean with temp of about 4.5 to 5 Deg.C) insulated by a few km of rock and mantle from the planet core with temps of several 1000 deg. What will be the convectional transfer from the planet core to the oceans. It must be very small.
If the oceans are ’storing heat” in the tropics as a net gain from the day /night radiative balance then it will be transported by currents to a midlatitude where the balance is negative wit ocean currents at say 2 to 4 knots it will only take 2 or 3 months for the stored heat to reach those latitudes.
The absorption time from radiation is probably no better determined than the release time, but it is unlikely the two are equal. If the atmosphere is clear and the ocean calm, then absorption takes place over a depth range of several hundred meters, and the release takes place over less than a meter of depth range. But if there are waves and wind then the release is quite different by orders of magnitude. And, if Bob Tisdale, were on this post he’d undoubtedly bring up ENSO, in which storage and release takes place over many years, and the storage and release are not symmetric.
Bottom water in the Atlantic is about -2C and in the Pacific is perhaps +1 or +2. The coldest bottom water comes from the Arctic regions in the Atlantic sector. We do not have much data about historical temperature changes in bottom water, but we figure from oxygen isotope data that bottom water has been as warm as +15C at times in the past 50my.
Heat flow from the Earth’s interior has little direct effect on climate in the short term because it is quite puny; however, people have proposed that beneath the isolation of an ice cap, heat flow into the floor of the Arctic ocean might cause this ocean to overturn, open polynyas on the surface, and end an ice age–speculative but interesting.
Ninderthana (06:25:06) :
they actually occur because of long-term changes in the Earth’s rotation rate, that are being driven from outside the Earth. Why are most of you ignoring this fundamental result?
These results are now published in a compendium of papers in Russian and are available (In English) from me upon request.
I’d like a copy (In english). rog at tallbloke dot net.
Thanks
Kevin Kilty (05:20:53) :
I’d like to know, Leif, what was the context of this other thread?
http://wattsupwiththat.com/2009/08/06/long-debate-ended-over-cause-demise-of-ice-ages-solar-and-earth-wobble/#comment-172069