Let's Not Be Too Dense - 2

Fig. 1 Water is an uncommon liquid

Regular readers know how I learned where I should look to find the more obvious ocean waters in order to search for thermal expansion and contraction evidence.

It is somewhat like the serial bank robber who was finally nabbed, and was asked by the detective, "Righty, why do you persist in robbing banks?"

The previously Scot-free serial bank robber replied to the FBI agent, "Well copper, I did it for all of those years because that is where the money is."

So, to fit the metaphor, and to be worthy researchers, we would ask "where is the sea water that is being impacted by thermal expansion?"

And to be more precise, that place to search would be where the sea water is receiving most of the heat from the Sun during our era of increasing global warming.

The answer is the Southern Ocean:

"The vast Southern Ocean, which surrounds Antarctica, plays a starring role in the future of climate change. The global oceans together absorb over 90 percent of the excess heat in the climate system and roughly three-quarters of that heat uptake occurs in the Southern Ocean."

(Climate Central, emphasis added). The former "over 90 percent" is now calculated to be 93%.

Using 93% as the "over 90 percent", that final amount is 70% (93 * .75 = ~70%).

The graphic at Fig. 1 shows the strange nature of water in the sense that adding heat to either pure water or sea water does not ipso facto mean that the water will expand.

It could shrink, too.

It depends on the condition of the sea water at the time the heat is added or removed, (especially the in situ temperature).

The module I mentioned in a previous post (On Thermal Expansion & Thermal Contraction - 36)  generated the CSV files for producing the graphs at Fig. 2a - Fig. 2r below.

Today's graphs are about year to year changes in measured values.

Usually, graphs are based on measured values, not changes in measured values.

Some brief definitions:

CT changes: This value concerns the Conservative Temperature (CT) of the in situ location (year, latitude, longitude, depth level).

MDCT changes: These values concern the CT changes at which the Maximum Density (MDCT) takes place (Fig. 1).

Density Factor (DF) changes: This value represents the gap between CT and MDCT. When this gap is narrowing, thermal contraction is taking place. The degree of that thermal contraction depends on the size of the gap (in deg. C) between them. If they are equal, Maximum Denisty of that specific sea water has taken place.

Thermosteric Sea Level changes: These values concern the sea water volume changes due to sea water temperature, density, & salinity changes from year to year.

Note:

Typically, CT values must be equal to MDCT values for maximum density to have taken place. But, even when the CT is merely approaching the MDCT, i.e. the gap between them is narrowing, thermal contraction is taking place. The degree of that thermal contraction depends on the size of the gap (deg. C) between them. To the contrary, when that DF gap is increasing, thermal expansion is taking place. And of course, in the rare case that the CT is less than the MDCT, the opposite scenario takes place.

On a running total basis for these graphs, each value is calculated by subtracting the previous year value from the current year value.

All in all, the hypothesis depicted in the graphic at Fig. 1 is confirmed (density is a factor in thermal dynamics).

The previous post in this series is here.

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Fig. 2a

Fig. 2b

Fig. 2c

Fig. 2d

Fig. 2e

Fig. 2f

Fig. 2g

Fig. 2h

Fig. 2i

Fig. 2j

Fig. 2k

Fig. 2l

Fig. 2m

Fig. 2n

Fig. 2o

Fig. 2p

Fig. 2q

Fig. 2r

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Why Sea Level Rise May Be The Greatest Threat To Civilization - 6

"The Doomsday Glacier"

Some regular and even some un-regular readers must wonder why Dredd Blog focuses on Antarctica so much.

They may wonder that because the ocean is vast.

But, the Southern Ocean which surrounds Antarctica is a small portion of the global ocean.

Don't feel left out, because it was not too very long ago that I found out too ... I found out why I had to change my focus too ... so ... you are not alone.

When I found out "the reason" it surprised me too:

This is why we need this focus:

"The vast Southern Ocean, which surrounds Antarctica, plays a starring role in the future of climate change. The global oceans together absorb over 90 percent of the excess heat in the climate system and roughly three-quarters of that heat uptake occurs in the Southern Ocean. In addition, the global oceans absorb around 25 percent of anthropogenic carbon dioxide emissions and the Southern Ocean alone accounts for about half of the uptake of CO2.

Despite its critical role in our climate system, the Southern Ocean has gone almost completely unobserved. Scientists have struggled to gather precise measurements because of the harsh environment and extreme remoteness. The changing dynamics of the Southern Ocean will in turn drive key aspects of our future climate, including how sensitive the Earth will be to further warming and increases in carbon dioxide emissions. As a result, improved observations are crucial to helping scientists understand and predict how our climate will change."

(Antarctica 2.0 - 3, quoting Climate Central). When the sea level is rising and the net result of thermal expansion / contraction totals is a minor player, [a small number], then melting tidewater glaciers and other melting ice in the Cryosphere quite obviously must be the major player.

(On Thermal Expansion & Thermal Contraction - 36, emphasis added). Another reason for such coverage can also be scary:

"Thwaites Glacier in West Antarctica is so remote that only 28 human beings have ever set foot on it.

Knut Christianson, a 33-year-old glaciologist at the University of Washington, has been there twice.

A few years ago, Christianson and a team of seven scientists traveled more than 1,000 miles from McMurdo Station, the main research base in Antarctica, to spend six weeks on Thwaites ...

They were mapping a future global disaster. As the world warms, determining exactly how quickly ice melts and seas rise may be one of the most important questions of our time ... If there is going to be a climate catastrophe ... it's probably going to start at Thwaites. The trouble with Thwaites, which is one of the largest glaciers on the planet, is that ...  instead of melting slowly like an ice cube on a summer day, it is more like a house of cards: It's stable until it is pushed too far, then it collapses... Seas will rise about 10 feet in many parts of the world; in New York and Boston, because of the way gravity pushes water around the planet, the waters will rise even higher, as much as 13 feet ... West Antarctica could do to the coastlines of the world what Hurricane Sandy did in a few hours to New York City," explains Richard Alley ... Except when the water comes in, it doesn't go away in a few hours – it stays."

(The Doomsday Glacier, emphasis added). So, what does that have to do with sea ports and flat landers?

Flat landers like to eat, drink, be merry, and pass it on to their progeny, but these habits have now become entwined with world sea ports:

"By volume, more than 95 percent of U.S. international trade moves through the nation's ports and harbors, with about 50 percent of these goods being hazardous materials."

(NOAA PORTS, emphasis added; cf. Ports & Harbors). Dredd Blog has been pointing that out for a while (Will This Float Your Boat?, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14) because McTell News and the U.S. government is reluctant to do so (Blind Willie McTell News, 2, 3, 4, 5, 6).

As Dredd Blog has pointed out, you flat landers (who think you will cheer when those "it can't happen here" elitists who live on the coast get their comeuppance) have no idea what will happen when civilization's sea ports go down (Why Sea Level Rise May Be The Greatest Threat To Civilization, 2, 3, 4, 5).

I will continue to watch the Southern Ocean (Antarctica 2.0, 2, 3, 4, 5, 6 [& supplements A, B, C, D, E, F]) because You Are Here with me.

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

Let's Not Be Too Dense

Fig. 1 Density Matters

I. Knowing Density

In a recent Dredd Blog post I quoted the World Ocean Database (WOD) Manual, and pointed out a very interesting quote in it:

The reason I have ventured into the sea water density issue is because of what is written in the TEOS-10 manual:

"Since the density of seawater is rarely measured, we recommend the approach illustrated in Figure 1 as a practical method to include the effects of composition anomalies on estimates of Absolute Salinity and density. When composition anomalies are not known, the algorithm of McDougall et al. (2012) may be used to estimate Absolute Salinity in terms of Practical Salinity and the spatial location of the measurement in the world oceans."

(TEOS-10 Manual, p. 14, p. 24 PDF).

(On Thermal Expansion & Thermal Contraction - 35, emphasis added). That could be quite significant.

As the graphs at Fig. 1 and Fig. 2 show, the maximum density temperature of the sea water is an important part of determining whether contraction or expansion will take place as the temperature of the sea water being analyzed changes.

Fig. 2 Opposite of Fig. 1

Unless one calculates the density and the maximum density temperature, one can not know exactly enough whether or not, or how much thermal contraction or thermal expansion is taking place at any given in situ context.

In other words, the degree of expansion or contraction taking place is impacted by how close CT is to the sea water maximum density in the in situ context the measurements were taken.

In other words one will not have a clue as to how much or even whether or not sea level is being impacted by the change in sea water temperature.

II. Easy

Furthermore, the density is quite easy to determine, and so is the maximum density temperature, when one is using the TEOS-10 software library to analyze in situ measurements.

Since the TEOS-10 library wast released about 8 years ago one does not need a pressure gauge onboard a CTD device or an ARGO float to determine sea water density.

That can be calculated using the TEOS-10 "gsw_ct_maxdensity" function.

III. Use Good Tools, Not Toys

While writing software modules and using actual in situ sea water temperature measurements around Antarctica, then generating graphs, I noticed that at times the Conservative Temperature and the Maximum Density Conservative Temperature could run parallel to one another.

"Does thermal contraction or expansion take place when they run parallel to one another?" I wondered.

Whether it does or not, thermal contraction and expansion can and does take place anyway.

The question is how much, because it is the net result (add expansion, subtract contractions) that matters.

IV. Conclusion

The graphs at Fig.1, Fig. 2, and Fig. 3 are hypothetical examples showing where the sea water temperature and the maximum density temperature could cause different and even opposite results.

Fig. 3

The initial data indicates that even though the sea water temperature (Conservative Temperature - CT) was increasing quite a bit the thermosteric volume was not.

I will finish those modules soon, and share the results.

Hopefully we can determine if and how much this impacts the thermal expansion hypothesis.

The hypothesis I am talking about is the one that alleges that thermal expansion is the main cause of sea level rise.

UPDATE conclusion: Fig. 2 is the most common of all by far.

The rare Fig. 1 and Fig. 3 phenomena are not major considerations, so from now on I will focus on the Fig. 2 phenomenon.

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Here is a preliminary list I compiled after parsing all WOD zones (1968-2016) at all 33 depth levels:

year 2007, CT [0.756752], MDCT [2.16742] @ zone 7715 @ depth 0m
year 2007, CT [0.125456], MDCT [2.08418] @ zone 7715 @ depth 10m
year 2007, CT [-0.68055], MDCT [2.03381] @ zone 7715 @ depth 20m
year 2007, CT [-1.29632], MDCT [2.06461] @ zone 7715 @ depth 30m
year 2007, CT [-1.05918], MDCT [2.2507] @ zone 7715 @ depth 50m
year 2007, CT [-1.44098], MDCT [2.35989] @ zone 7715 @ depth 75m
....
year 1988, CT [0.744434], MDCT [2.81778] @ zone 1601 @ depth 0m

year 2015, CT [2.64246], MDCT [2.89663] @ zone 1602 @ depth 0m
year 2015, CT [2.63883], MDCT [2.87479] @ zone 1602 @ depth 10m

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See updated graphs here.

The next post in this series is here.

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