Forcing The Ocean To Confess

Guest Post by Willis Eschenbach

According to the current climate paradigm, if the forcing (total downwelling energy) increases, a combination of two things happens. Some of the additional incoming energy (forcing) goes into heating the surface, and some goes into heating the ocean. Lately there’s been much furor about what the Levitus ocean data says about how much energy has gone into heating the ocean, from the surface down to 2000 metres depth. I discussed some of these issues in The Layers of Meaning in Levitus.

I find this furor somewhat curious, in that the trends and variations in the heat content of the global 0-2000 metre layer of the ocean are so small. The size is disguised by the use of units of 10^22 joules of energy … not an easy one to wrap my head around. So what I’ve done is I’ve looked at the annual change in heat content of the upper ocean (0-2000m). Then I’ve calculated the global forcing (in watts per square metre, written here as “W/m2”) that would be necessary to move that much heat into or out of the ocean. Figure 1 gives the results, where heat going into the ocean is shown as a positive forcing, and heat coming out as a negative forcing.

annual forcing into out of the oceanFigure 1. Annual heat into/out of the ocean, in units of watts per square metre. 

I found several things to be interesting about the energy that’s gone into or come out of the ocean on an annual basis.

The first one is how small the average value of the forcing actually is. On average, little energy is going into the ocean, only two-tenths of a watt per square metre. In a world where the 24/7 average downwelling energy is about half a kilowatt per square metre, that’s tiny, lost in the noise. Nor does it portend much heating “in the pipeline”, whatever that may mean.

The second is that neither the average forcing, nor the trend in that forcing, are significantly different from zero. It’s somewhat of a surprise.

The third is that in addition to the mean not being significantly different from zero, only a few of the individual years have a forcing  that is distinguishable from zero.

Those were a surprise because with all of the hollering about Trenberth’s missing heat and the Levitus ocean data, I’d expected to find that we could tell something from the Levitus’s numbers.

But unfortunately, there’s still way too much uncertainty to even tell if either the mean or the trend of the energy going into the ocean are different from zero … kinda limits our options when it comes to drawing conclusions.

w.

DATA: Ocean temperature figures are from NOAA, my spreadsheet is here.

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Chris R.
June 20, 2013 9:16 am

And the beat goes on–see this interview of Hans von Storch in
the online edition of Der Spiegel. (Don’t worry, it’s
been translated to English.)
http://www.spiegel.de/international/world/interview-hans-von-storch-on-problems-with-climate-change-models-a-906721.html
Note the careful phrasing, but the rigid adherence to the defense of
AGW:
— Simulations show a “pause” in global warming lasting 15 years or
longer less than 2% of the time, BUT–“… in five years, at the latest, we
will need to acknowledge that something is fundamentally wrong with
our climate models.” Move the goalposts again, why don’t you?
— “[Ocean] Temperatures at depths greater than 700 meters (2,300 feet)
appear to have increased more than ever before.”
— “The IPCC’s predictions have been conservative. And, considering the
uncertainties, I think this is correct.”
— Asked if there were findings related to global warming that worried him:
“The potential acidification of the oceans due to CO2 entering them
from the atmosphere. This is a phenomenon that seems sinister to me…”

Bart
June 20, 2013 9:42 am

Willis Eschenbach says:
June 20, 2013 at 12:09 am
David Riser says:
June 19, 2013 at 10:51 pm
This is a question of precision versus accuracy. The oceans are vast. The floats only sample them at specific locations. So, while the individual measurements can be infinitely precise, the overall mean value is not necessarily accurate.
Kristian says:
June 20, 2013 at 2:16 am
“Still you seem to be arguing that the inferred downward atmospheric radiative flux is somehow capable of heating the surface/ocean (like the solar flux) to a higher temperature than what the Sun could manage on its own.”
Your disconnect is in not thinking of this as a continuous flow problem. Consider this analogy. You have a pot of water sitting in the Sun – assume there is no night. Eventually, the water will evaporate and the pot will be dry. So, you put in a hose which continually trickles water in. The level of water in the pot reaches an equilibrium where the rate of evaporation is equal to the rate of the trickle.
Now, you put a transparent but permeable covering of some sort over the pot. It does not prevent evaporation, but it slows it down. What happens to the level of water in the pot?
It rises, and as it does so, the rate of evaporation increases. At some point, you again reach an equllibrium in which the rate of the trickle is equal to the rate of evaporation. But, the level of water is higher than it was before.
That is how the GHE works. It does not create a permanent heat flow imbalance, just as in the analogy, the covering over the pot does not cause a permanent imbalance between evaporation and trickle input. It just causes one long enough that the stored heat, or water in the case of the analogy, increases. All of the heat energy is coming from the Sun, just as in the analogy, all of the water input is coming from the trickle hose. The greenhouse gases, or the cover on the pot, merely establish the equilibrium level for the stored heat or water level.
BUT, that is only a simple analogy in which all other processes influencing the water level in the pot remain fixed. Suppose that we put a hole in the side of the pot at the level of water before we put the cover on. Now, when the water level rises, it will just spill out the hole. So, putting the cover over the pot has no net effect on the water level. The hole comprises a negative feedback, which maintains the water level below a particular point.
That is the discussion which learned people are having. All things being equal, an increase in greenhouse gases should increase the level of heat stored in the Earth’s land/ocean/atmospheric system. But, all things are not equal. There are many “holes” or negative feedback reactions through which the virtual excess heat can escape, or be blocked from entering in the first place.

Marlow Metcalf
June 20, 2013 9:52 am

So does this mean that the only way to significantly increase ocean heat is to increase the amount of water in the ocean? If so then if the ocean level is a little less than in say 1600 AD would that mean there is less heat in the ocean now than before the Little Ice Age?

Ximinyr
June 20, 2013 10:01 am

Manfred is correct.
Manfred is incorrect.
Look, this isn’t difficult. You have calculated the annual change in OHC, and taken the trend of that.
That is not the trend of OHC.
The function f(x)=x has a trend of 1.
But you have plotted the point-by-point difference in f(x), which are the points {1,1,1,1,1,…}, and taken the trend OF THAT, which is obviously zero.
It’s obvious — your calculated trends in forcing are essentially the 2nd derivative of OHC, not the 1st derivative.

Ximinyr
June 20, 2013 10:09 am

Suppose the OHC for year Y is
OHC(Y)=kY
where k is a constant. This clearly has a trend of k units per year.
Your graph plots the forcing:
F(Y) = [OHC(Y)-OHC(Y-1)]/A
where A is the area of the ocean. Obviously F(Y)=k/A, a constant, for all Y.
Thus the forcing has a trend of 0. That’s what your graph is showing.
But clearly the trend of the OHC is *not* zero, it is k, i.e the ocean is warming.
Q.E.D.
Really, Willis, this is obvious.

Ximinyr
June 20, 2013 10:13 am

Willis wrote:
Manfred is correct. The graph is of the first derivative of OHC, in units of W/m2.
The points in the graph are the value of the first derivative of OHC(t).
Hence, its trend is the second derivative. Obviously.
My example with OHC(Y) just above makes this very clear.

Ximinyr
June 20, 2013 10:36 am

Instead, the OHC represents the ongoing balance between two very large flows—the flow of sunlight and longwave radiation into the ocean, and the same sized flow of energy out of the ocean in the form of radiation, conduction to the atmosphere, and evaporation.
again, you are ignoring heat that travels out the bottom of the 0-2000 m layer.

Ximinyr
June 20, 2013 10:57 am

Willis: you are getting lost in the statistics.
Again: you aren’t calculating the trend in OHC!
you are calculating the trend of its derivative.
these two things have very different statistical results, because the first is increasing strongly, but the second isn’t.
that’s hardly surprising — that the 2nd derivative fluctuates more than the 1st derivative. differences of differences often do.
the problem is with your understanding of the data, not the statistics. look at my example at 10:09 am above, for OHC(Y)=kY. This is a clean example where statistics can be ignored.
What does your methodology, as in your post, predict for the trend in forcing?

Eric H.
June 20, 2013 10:58 am

kadaka (KD Knoebel) says:
June 20, 2013 at 6:07 am
From Eric H. on June 20, 2013 at 3:08 am:
So the sun and clouds (drivers) are responding to CO2 (bad alignment)? How does that work exactly?
“Is it that hard for you to figure out?”
Actually it is. Can you please provide a reference that shows the sun responding to CO2? I would love to read it.
I read climate blogs because the debate and science interests me. I seldom post and when I do I do so respectfully and I am usually asking questions.
Unlike you, I don’t harass others and engage in petty fights in order to try and look smart, in short kadaka, I don’t wrestle with pigs and I don’t argue with idiots.
I am done with you,
Eric
PS I have over 30 years experience in auto mechanics… as a profession, business, and hobby…Don’t quit your day job.

Ximinyr
June 20, 2013 11:20 am

willis: my point is that by looking only at the balance at the surface of the ocean you are ignoring energy that goes in and out of the bottom of the 0-2000 m region,
but that’s a minor point. the major point is your misinterpretation and misuse of the data. your result says nothing like what you have claimed.

Bart
June 20, 2013 11:39 am

Willis Eschenbach says:
June 20, 2013 at 10:33 am
“So there are four examples of downward transport mechanisms, where you said there were none.”
OK, you’ve made your point. There are avenues for deep water mixing of upper heated levels. However, it still does not jibe with me.
I grasp what you are saying with the following analogy. You have a bucket of clear water. You take a pitcher and, from a height, start pouring blue tinted water in. By the force of gravity, it plunges down in a narrow channel, creating a localized gradient from deep blue at the surface to lighter blue with depth. But, that gradient doesn’t exist everywhere, so on average, as the plume spreads out below, you get bluer depths than in the upper layers.
Here’s where I see that scenario failing to match the real world. Even though there is mixing, there is nothing like a focused jet of tinted waters rocketing to the depths. Moreover, we are concerned specifically with heat generated by excess CO2, and that is not coming in at one particular focal point, but broadly distributed over the entire body of oceans.
So, it’s more like raining blue tinted water over the entire bucket, and then swirling a portion of the surface downward in a whirlpool eddy. Does this create a deeper blue at depth than in the upper layers? I have difficulty in imagining that.

Bart
June 20, 2013 11:58 am

Ximinyr says:
June 20, 2013 at 10:09 am
I think I see your point, though my reading is really only cursory. However, let me ask you this.
If the mean of a process is not statistically significant, how can the slope of the accumulation be so?
The answer to the question does depend on the autocorrelation of the process but, assuming your estimate of the mean is optimal, then it is tautological that you cannot estimate the slope of its accumulation better than that. If you could, then the estimate of the mean was not optimal.
For example, if you take a sequence of zero mean white noise and accumulate it, you end up with a random walk. You may will find that a finite sample of that random walk process displays a readily apparent trend, and be able to fit a slope to it. However, the uncertainty in each point of that process is increasing with the square root of the number of samples accumulated, and so your apparent trend is merely a manifestation of the accumulating noise in the original sequence. The trend could reverse tomorrow, and so your estimate has no predictive power. Your best estimate of the future is actually the final value of the accumulation.

Ximinyr
June 20, 2013 12:23 pm

Bart, I don’t immediately know the answer to your question, which is a good one as the random walk example makes clear.
Intuition often fails when dealing with autocorrelation, but I have an intuitive sense, for whatever that’s worth, that the slope of a set of nearly linear points can be statistically significant while the slope of the set of their differences may be statistically near zero.
I just have a very hard time believing that the NOAA plot of 0-2000 m OHC as a function of time does not have a statistically significant positive slope, even with autocorrelation. I could be convinced if (1) someone did a calculation of the slope using the OHC data directly, and not the slope of their differences, and (2) they used a better model for the autocorrelation than the Nychka equation.

June 20, 2013 12:34 pm

jai mitchell sez:
“”” maybe about 1.2% increased absorption in the tropics would do it. See the following graphic.
http://oceanworld.tamu.edu/resources/ocng_textbook/chapter05/Images/Fig5-7.htm
The tropical net energy absorbed in the latitudes of -30 to +30 is about 40 Watts per meter squared on average.”””
That sounds like you are saying the tropical oceans absorb this apparently small increase in the energy flux across the vast expanses of the oceans and then magically concentrate it in the small areas of the tropical oceans where there might be deep downwelling. Nice trick.

Bart
June 20, 2013 1:32 pm

Ximinyr says:
June 20, 2013 at 12:23 pm
“…I have an intuitive sense, for whatever that’s worth, that the slope of a set of nearly linear points can be statistically significant while the [mean] of the set of their differences may be statistically near zero.”
Take a closer look at the plot of samples of Brownian motion at the Wikipedia link I gave previously. Are there periods in which there appear to be a linear slopes? Are they real?

June 20, 2013 1:35 pm

Willis Eschenbach says:
June 19, 2013 at 6:37 pm
==========================
Forey writes (p.37: http://books.google.com/books?id=wHZ6WwqbrmkC&pg=PA37&lpg=PA37&dq=coelacanth+cave+temperature&source=bl&ots=RHe2hmN7TZ&sig=2x3cq-kyLPQN3SydSah6Gp6ITzc&hl=en&sa=X&ei=GuzBUfiHNuKUywGC9oGIAw&ved=0CEYQ6AEwAw#v=onepage&q=coelacanth%20cave%20temperature&f=false):
“It is generally believed that the minimum depth distribution of Latimeria is governed by temperature because the maximum oxygen saturation of coelacanth haemoglobin occurs at 15-18°C. Latimeria is unlikely to be able to tolerate temperatures exceeding 22°C for any length of time. The depth of observed coelacanths does correlate with the depth of the 18°C thermocline…
“Within these caves the water temperature was generally higher and in some cases reached 23°C (Fricke et al., 1991: table 1). This observation, and the fact that the water temperature of the Mozambique find (Bruton et al., 1992) was 28-30°C, calls into question the preferred temperature tolerance (Huges and Itasawa, 1972).”
A few points:
1) Only big coelecanths have been caught or observed; juvenile behavior remains unknown. Their large size, nocturnal and cold water preferences, cave hiding and fatty tissue are probably all evolved to avoid sharks (and pleisoraurs, orcas, etc.), which prefer warmer T ranges (and daylight?).
2) Morphologically the coelacanth is similar to its Devonian ancestors; physiologically it has adapted to colder T’s than those in which it’s ancestors evolved lungs. It is a big enough fish to generate an internal T slightly higher than its surroundings in spite of its low metabolism–how much higher I can’t say. It’s a very safe bet the coelacanth’s metabolism has decreased greatly in the last 300my.
Granted, a “cold blooded” fish of extraordinarily low metabolism (apparently calculated by observation of feeding habits and stomach contents–they never survive at the surface) could not be expected to contribute much heat to its surrounding water–maybe less even than ground heat (back to down welling warm water). But the assumption that an ectotherm would always seek out colder water to keep its energy expenditure low runs into a brick wall of problems, first and obviously that of the wide T range of ectothermic adaptation. Some like it hot; some like it cold. They don’t care if they have to burn a few more calories–they will try to keep their body at whatever T their enzymes have evolved to work at.
And notice that this notion of T and calories has reversed the argument: ectotherms are defined by their inability to control their temperature by burning calories, and here is claimed that a higher T would automatically entail a metabolic increase, as if these ectotherms were really fur-less endotherms all along, albeit with broad T tolerances (I think they were).
Now where were we? The adults do spend the day in caves; we don’t know what the little ones do. No, communal body heat isn’t good for much with such a low metabolism. Do they prefer warm caves over cold? Nobody knows. They probably stay in caves to hide from predators. Circulation must be poor in the caves, meaning low oxygen, meaning low metabolism, but they only want to rest anyway. That they sleep in caves means they hug steep shorelines, avoid open water, move vertically rather than horizontally (compared to others), and so are able to choose an ideal T with minimum effort.
Hemoglobin suggests the coelecanths need cold water, as does their inability to survive capture, while the Mozambique specimens prefer warmer water. Granted, cave resting doesn’t tell us much except that they can’t survive open water during the day. Their low metabolism is probably a product of cave hiding, a product of avoiding predators. They gave up their lungs and they gave up their primeval metabolism and tropical physiology in order to survive for 300my while all their kin went extinct.
So why are the caves warm? They most slope upwards, for one thing. –AGF

Trick
June 20, 2013 1:49 pm

Willis’ top post: “..heat content of the global 0-2000 metre layer of the ocean…”, “” …change in heat content of the upper ocean..”, “..move that much heat into or out of the ocean…”,”..Figure 1 gives the results, where heat going into the ocean…”
1) Fig. 1 shows energy flux density vs. time not heat vs. time; the caloric theory had some usefulness in its time but like slide rules, we have moved on to energy flux densities as shown.
2) “..the energy that’s gone into or come out of the ocean on an annual basis” – that’s better, like calculators replacing slide rules.
Willis’ reply to Kristian 6/20 2:03am:
“Heat ….is a concept, not a physical..”
Think Willis will then agree that the term “energy” is the more appropriate physical term to use in the top post e.g. “…energy content of the global ocean”, “…change in energy content…”, “…move that much energy…” are more modern & correct than “heat content”. And better understood.
So agree, the difference in term causes much unneeded electron death. And much unneeded blog reader irritation.

RT
June 20, 2013 2:10 pm

In response to:
Anthony Watts says:
June 19, 2013 at 4:13 am
I would LOVE to hear Cook’s explanation for the several periods of a few years length when the ocean lost considerable heat content but the atmosphere did not gain any. The heat must be hiding in rocks too. Sneaky heat.

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