On Thermal Expansion & Thermal Contraction

Fig. 1a

Thermal expansion of pure water does not have the same thermodynamic events that the thermal expansion of sea water has.

You can search the Internet and find videos of someone pouring pure water into a flask, making a mark on the flask, then heating the flask with a Bunsen Burner.

Then they will put another mark on the flask after the water warms, showing that the heat has caused the water to increase in volume.

They then are apt to declare that this proves that thermal expansion is the major cause of sea level rise because "as water warms it expands."

The problem with this Mickey Mouse trick is that
if the pure water they use is at a temperature that is below its maximum density temperature of 4 deg. C, when they apply heat to the flask the pure water will contract (lose volume) rather than expand (gain volume), until the pure water temperature reaches the maximum density temperature of 4 deg C at which time it will begin to expand (as more heat is applied ... see Fig. 1a).

Fig. 1b

For example, if the pure water temperature is 2 degrees C and heat is applied, the water will contract (lose volume) until its temperature increases to the maximum density temperature of 4 deg C.

Determining the maximum density of sea water is more difficult than pure water because it contains molecules of other substances, and also is impacted by depth pressure (Is A New Age Of Pressure Upon Us? - 14).

Fig. 1c

The graphs at Fig. 1b and Fig. 1c show a history of the sea water temperature of in WOD Zone 5611 at 20 meters deep (Amundsen Sea area).

Following the principles enunciated in Fig. 1a, I have marked the expansion and contraction events to show the almost unbelievable expanding and contracting as the sea water temperature dips below the maximum density temperature (shown by the red line).

The gist of it is that when the sea water temperature is above the red line the volume change is the opposite of what it is when the sea water temperature is below the red line.

The non-marked-up version of the Fig. 1b graph is shown at Fig. 1c.

Today, I used only one zone specifically for emphasizing that the net balance derived by adding up the thermal expansion (pluses), and subtracting the thermal contractions (minuses) does not result in either "the major factor" or "a major factor" of sea level rise.

The graph at Fig. 1c, as well as the following graphs, were computed by using the TEOS-10 function gsw_ct_maxdensity to create the red line, and gsw_ct_from_t to generate the black line (see On Thermal Expansion & Thermal Contraction - 35).

Each of the following graphs (Fig. 2a - Fig. 2p) are generated from data of a different depth, but they are all constructed from WOD data @ WOD Zone 5611.

See if you can determine expansion and contraction segments of the black line as I did in Fig. 1b. [Remember to follow the time line flow (left to right): Answers]

Remember that (in terms of whether expansion or contraction will take place) when the black line is above the red line, sea water thermodynamics are the opposite from when the black line is below (cooler than) the red line (cf On Thermal Expansion & Thermal Contraction - 35).

Finally, yes the lines are somewhat jerky because that area of the world makes it difficult to take measurements, so there are not as many measurements over the decades as we would like (especially at deepest depths).

The previous post in this series is here.