In Search Of Ocean Heat - 20

Fig. 1 Photons-All Sectors

I. Potential Enthalpy

In today's post we are taking a look at ocean heat content, a.k.a. "potential enthalpy" (h^o) in Antarctic waters.

We know that ocean heat content (amount of joules per kg) in seawater is radiated to colder water around it.

In two previous posts of this series we took a look at, among other things, how potential enthalpy (h^o) is calculated  (In Search Of Ocean Heat - 18, In Search Of Ocean Heat - 19). It is a TEOS-10 concept.

II. Graphs

Today's graphs (Fig. 1 - Fig. 9, from Sectors A, B, and All-Sectors) indicate that in measurements in Epipelagic depths some or all of the values derived from potential enthalpy values become negative numbers.

Fig. 2 Photons-Sector B

That is the opposite of what happens in seawater north of Antarctica and south of the Arctic Ocean where warmer seawater prevails at the surface or near the surface.

At polar regions the ocean surface seawater begins at the bottom of any floating ice shelf flowing from land-based glaciers.

So, there is some question as to what negative potential enthalpy (h^o) values mean when they are calculated using the in situ measurement averages of temperature and salinity.

It is reasonable to conclude that negative (h^o) values indicate how much warming (Conservative Temperature increase) would have to take place before the potential enthalpy value becomes a positive number again.

Fig. 3 Photons-Sector A

The most surprising take-home is that the warmer waters are generally down below the Epipelagic depths and in the Mesopelagic and Bathypelagic depths in Antarctic tidewaters.

Which means that the Second Law of Thermodynamics (hot/warm flows to cold/cooler) would indicate that the infrared photon flow is from deeper to shallower.

The laws of the thermodynamic effects in the ocean is solid science according to probably the most famous scientist of our time.

The TEOS-10 version is Josiah Gibbs inspired, of which Albert Einstein was quite respectful:

"Listening to Gibbs, who is perhaps the most influential historical voice in ocean thermodynamics (encapsulated in TEOS-10) would also help:

"Albert Einstein called him 'the greatest mind in American history.' Gibbs’s studies of thermodynamics and discoveries in statistical mechanics paved the way for many of Einstein’s later discoveries."

(American Physical Society or APSloane). Especially since "encapsulated" means:

"TEOS-10 is based on a Gibbs function formulation from which all thermodynamic properties of seawater (density, enthalpy, entropy sound speed, etc.) can be derived in a thermodynamically consistent manner."

(Thermodynamic Equation Of Seawater - 2010, emphasis added)."

(In Search Of Ocean Heat - 5). The graph lines were projected by calculating the 'height' (Z), pressure (P), Absolute Salinity (SA), Conservative Temperature (CT) of World Ocean Database and Princeton University in situ measurements.

Fig. 4 (h^o)-All Sectors

Those detailed measurements have been taken around the coast of Antarctica for long enough that we can see that the laws of thermodynamics are clearly major players.

That is why Dredd Blog presents graphs and other data generated by the TEOS-10 C++ library [ZIP file].

When TEOS-10 is in the toolbox of oceanographic researchers they will be able to use Gibbs functions along with many others to determine what researchers without them are likely to miss (Thermosteric Sealevel Change Revisited - 4).

III. Complaints By Scientists

Fig. 5 (h^o)-Sector B

Since Albert Einstein himself said that the thermodynamics oriented work by Gibbs was likely to outlast, in terms of accuracy, quantum mechanics of more speculative sorts, let's listen to some of the scientists who agree with Albert's suspicions:

 

Alexander Unzicker

The Physics Detective

These contra hypotheses are not coming from scientists who reject quantum mechanics, no, they only complain about the inaccurate hypotheses running amok in some of the work of current physics researchers.

Fig. 6 (h^o)-Sector A

Like Dredd Blog, they merely want a better body of quantum physics which is not composed of non-falsifiable hypotheses, radical speculation, and unverified allegations (e.g. Small Brains Considered - 7).

The "contra" science at issue is not limited to quantum mechanics and unfathomable subjects.

Note that a team of prominent oceanographers are concerned that oceanographic related textbooks do not understand or present sound ocean heat dynamics.

Over the years Dredd Blog has furnished posts featuring concerns scientists have about this and related issues:

Fig. 7 CT-All Sectors

"The quest in this work is to derive a variable that is conservative, independent of adiabatic changes in pressure, and whose conservation equation is the oceanic version of the first law of thermodynamics. That is, we seek a variable whose advection and diffusion can be interpreted as the advection and diffusion of ‘heat.’ In other words, we seek to answer the question, ‘what is heat’ in the ocean?
     ...

The variable that is currently used for this purpose in ocean models is potential temperature referenced to the sea surface, θ, but it does not accurately represent the conservation of heat because of (i) the variation of specific heat with salinity and (ii) the dependence of the total differential of enthalpy on variations of salinity.
...

For example, an increase in pressure of 107 Pa (1000 dbar), without exchange of heat or salt, causes a change in enthalpy that is equivalent to about 2.5ЊC. We show in this paper that in contrast to enthalpy, potential enthalpy does have the desired properties to embody the meaning of the first law.

    ...

Fig. 8 CT-Sector B

Present treatment of oceanic heat fluxes is clearly inconsistent. Ocean models treat potential temperature as a conservative variable and calculate the heat flux across oceanic sections using a constant value of heat capacity. By contrast, heat flux through sections of observed data is often calculated using a variable specific heat multiplying the flux of potential temperature per unit area (Bryan 1962; Macdonald et al. 1994; Saunders 1995; Bacon and Fofonoff 1996). Here it is shown that the theoretical justification of this second approach is flawed on three counts. While the errors involved are small, it is clearly less than satisfactory to have conflicting practices in the observational and modeling parts of physical oceanography, particularly as an accurate and convenient solution can be found.
    ...
 it is perfectly valid to talk of potential enthalpy, h0, as the 'heat content' ...”

(Potential Enthalpy: A Conservative Oceanic Variable for Evaluating Heat Content and Heat Fluxes, McDougall 2003, pp. 945-46, emphasis added ...

(In Search Of Ocean Heat, Dredd Blog 2018). These scientists are for real.

Even the publication "Oceanography The Official Magazine of The Oceanography Society" in a recent issue asked:

"Can Climate Models Be Trusted?

Fig. 9 CT-Sector A

'Climate models have long predicted a significant AMOC slowdown in response to global warming, including a corresponding cold blob (see Figure 12 for a recent version). In fact, I wrote two commentary pieces for Nature on that topic in the 1990s (Rahmstorf, 1997, 1999), and then as now, the amount of predicted weakening differed greatly among different models. The latest, sixth IPCC report found that, even for a low emissions scenario, the AMOC will weaken between 4% and 46% by the year 2100, depending on the model. In the high emissions scenario, the reduction ranges between 17% and 55% (IPCC, 2021). The IPCC report also concluded: “While there is medium confidence that the projected decline in the AMOC will not involve an abrupt collapse before 2100, such a collapse might be triggered by an unexpected meltwater influx from the Greenland Ice Sheet.'

...

'Implications: Uncertainty Is Not Our Friend

'The risk of a critical AMOC transition is real and very serious, even if we cannot confidently predict when and whether this will happen. ' "

(Oceanography Journal, 2024, emphasis added). Take that seriously.

IV. Closing Comments

All we are saying is give accuracy a chance by using up-to-date official developments:

"TEOS-10 (Thermodynamic Equation of Seawater - 2010) is the international standard for the use and calculation of the thermodynamic properties of seawater" 

(Wikipedia). It has been over a decade since TEOS-10 was instituted.

The previous post in this series is here.