Thermosteric Sealevel Change Revisited

Once Upon A Time

I. Catch The Wind

Thermosteric dynamics are most often called "Thermal expansion" so that is the terminology that has been used on Dredd Blog.

But even after all of these years the Warming Commentariat still does not explain why they:

1) don't mention thermal contraction;

2) don't mention the depth levels that exist and at the same time contain different seawater temperatures and expansion/contraction compared to other levels above or below them;

3) don't mention the thermal coefficient;

4) don't mention the volume of the seawater (length, width, height) depth level section they are analyzing;

5) don't mention that without temperature CHANGE there is no thermal expansion or contraction;

6) don't mention TEOS-10 (the official oceanography standard).

(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, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51). I have tried to address all that but "Ah but I may as well try to catch the wind" (Donovan).

Today I present information on five ocean groups composted of twenty-five ocean areas:

GROUP 0
Arctic
Southern
North Sea
Bering Sea
Sea of Okhotsk

GROUP 1
Indian
Red Sea
Sulu Sea
Baltic Sea
Arabian Sea

GROUP 2
Pacific
Yellow Sea
Sea of Japan
Andaman Sea
Black Sea

GROUP 3
Atlantic
Hudson Bay
Caribbean Sea
Gulf of Mexico
Bay of Bengal

GROUP 4
Mediterranean
Seto Inland Sea
South China Sea
Persian Gulf
Adriatic Sea

The in situ temperature measurements are, as usual, derived from the World Ocean Database then converted to TEOS-10 values using the TEOS-10 C++ software.

The following graphs detail the results:

Graph One

Graph Two

Graph One shows the thermal expansion/contraction of the 5 groups (25 oceans) averaged together as well as their cumulative totals.

Graph Two shows the lines that all 5 groups (all 25 oceans) produce when graphed together.

II. How To

The method used was: 1) gather WOD data and generate temperature, salinity, depth, and volume values at 33 depth levels (slices of the ocean from the surface to the bottom); 2) use TEOS-10 to generate the thermal expansion coefficient; 3) calculate the thermal expansion/contraction using those values (it is a negative value when thermal contraction takes place).

That is, in English 

"thermal_expansion equals mass_unit_volume multiplied by (1.0 + (thermal_expansion_coefficient multiplied by (current_temperature - previous_temperature))"

In the mathematics language that is:

V1 = V0 * (1.0 + (B * DT))

where:

V0 = mass_unit_vol
DT = D - T
D = current temperature
B = thermal expansion/contraction coefficient (TEC);
T = previous temperature
V1 = thermal expansion/contraction (volume change)

There is one thing that becomes obvious at first blush (notice: current temperature minus previous temperature) which is that when there is no temperature change (5 degrees minus 5 degrees, 5-5 = 0) there is no thermal expansion or contraction.

Compare the sea level change at US states (The US States of Sea Level Change, 2, 3) with thermal expansion and it becomes more clear that more Cryosphere ice is melting than previously thought (Widespread seawater intrusions beneath the grounded ice of Thwaites Glacier, West Antarctica); which means that thermosteric dynamics are less of a player than previously thought.

Tell it like it is Donovan:

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