On Thermal Expansion & Thermal Contraction - 33

W.E.C. Laboratory

I. Background

During this series I have been to several "places" in search of a better way of calculating the impact of global warming induced climate change on the sea level of the oceans (On Thermal Expansion & Thermal Contraction, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32).

Along the road some good locales that store data with which to pursue answers have been discovered and used: e.g. Permanent Service for Mean Sea Level (PSMSL), World Ocean Database (WOD), Southern Ocean Carbon and Climate Observations and Modeling project (SOCCOM), and Thermodynamic Equation Of Seawater - 2010 (TEOS-10).

Finally, I decided to look deep into the scientific literature to see where the foundation of the myth that thermal expansion (thermosteric volume change) has been "the" or "a" major factor in sea level rise.

II. Eureka

I began the latest probe into the search for "the holy grail of thermal expansion theory" with a recent paper "Climate-change–driven accelerated sea-level rise detected in the altimeter era" (being a big fan of "the altimeter era" and all).

I proceeded, following citations in that paper to other citations, until in one of them I found a "eureka!" disclosure:

"To quantify the variability of thermosteric sea level, we present time series and linear trends of globally averaged thermosteric sea level for the 0 – 700 m and 0 – 3000 m layers in Figure 1 (see Antonov et al. [2002] for details of thermosteric sea level computation)."

(Antonov 2005, PDF, emphasis added). Finally, I was about to peruse the basic calculations that were used to determine that thermal expansion has been "the major," or at least "a major," cause of sea level rise since forever.

I parsed out this:

"The thermal expansion theory of the mean sea level rise is based on (1) the fundamental physical property of seawater density to decrease [OR] (increase) when heat is added [OR] (removed), (2) the ability of the world ocean to store a substantial amount of heat in its deep layers (see Levitus et al. [2000] for recent observational evidence), and (3) observed trends in the surface temperature over the 20th century [e.g., Hansen et al., 1999]. [PRE-TEOS] Model computations explain more than two thirds of sea level rise by the thermal expansion of the world ocean [Church et al., 1991; De Wolde et al., 1995; Warrick et al., 1996; Stouffer and Manabe, 1999]."

(Antonov 2002, PDF). The author went on to explain:

"We have used data from the World Ocean Database 1998 (about 5.2 and 1.4 million temperature and salinity profiles, respectively) [Levitus et al., 1998] to prepare objectively analyzed temperature and salinity anomaly fields for 5-year running composites for the 1948 – 1996 period."

(ibid). Oh boy, "Model computations explain" eh? ... but what about this:

"Presented here are two approaches to a resolution of these problems. The first is morphological, based on the limiting values of observed trends of twentieth century relative sea-level rise as a function of distance from the centres of the ice loads at last glacial maximum. This observational approach, which does not depend on a geophysical model of GIA, supports values of GSLR near 2 mm yrK1. The second approach involves an analysis of long records of tide-gauge and hydrographic (in situ temperature and salinity) observations in the Pacific and Atlantic Oceans. It was found that sea-level trends from tide-gauges, which reflect both mass and volume change, are 2–3 times higher than rates based on hydrographic data which reveal only volume change. These results support those studies that put the twentieth century rate near 2 mm yrK1, thereby indicating that mass increase plays a much larger role than ocean warming in twentieth century GSLR."

(On the rate and causes of twentieth century sea-level rise). Who ya gonna call?

Regular readers know what was going through my mind, but I will write some of it down for the sake of irregular readers.

III. The Solution to Eradicating the Myth

(Listen Up, Stop Trusting, and Start Verifying)

It was good that they (Antonov, 2002) used WOD data, but the use of "about 5.2 and 1.4 million temperature and salinity profiles respectively" is problematic when it comes to calculating seawater thermodynamics (not because of quantity, but because they have to be pairs ... 1 temperature, 1 salinity, and 1 depth measurement, taken at the same time and location).

That would be, at most, "1.4 million temperature and salinity profiles" taken at the same depth and at the same time (if valid TEOS-10 results are sought).

Secondly, since their calculations were done prior to 2010, they were using (at best)  EOS-80 formulas which are now obsolete, having been replaced by official scientific institutions ("IOC","IAPSO", "IUGG", and "SCOR") with the TEOS-10 formulas:

What do you do?  (when you have been using a toolkit forever, then log on to the site one day to find the following):

"The SeaWater library of EOS-80 seawater properties is obsolete; it has been superseded by the Gibbs SeaWater (GSW) Oceanographic Toolbox of the International Thermodynamic Equation Of Seawater - 2010, (TEOS-10)"

(EOS-80, emphasis added). My solution was to change to using TEOS-10 for my thermal expansion and related oceanography oriented calculations (The World According To Measurements - 7).

(The World According To Measurements - 10). Which brings us to the law of the instrument ("I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail").

Trust and Faith are not valid replacements for verifications (The Pillars of Knowledge: Faith and Trust?).

IV. Conclusion

None of the paper trails that can be taken from within that paper (Antonov, 2002) or the latest one ("Climate-change–driven accelerated sea-level rise detected in the altimeter era") mention the new way to calculate the thermodynamics of seawater (called the Thermodynamic Equation Of Seawater).

The sooner they get in touch with those equations the better, because it takes a while to get used to it, and then begin to master it.

Regular readers know that is so, after watching me discover, struggle with, and hopefully someday master these tools and data.

The next post in this series is here, the previous post in this series is here.

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