The Bathtub Model Doesn't Hold Water - 2

Fig. A Dredd Blog Zones

In this series I began by going over some of the basics about "the bathtub" model.

The mantra that signals usage of the bathtub model is the phrase "global mean average sea level rise."

A sea level expert explains: "By taking the [global] average you're assuming something, and you're assuming it implicitly. You're assuming what we call the bathtub model" (The Bathtub Model Doesn't Hold Water, quoting Dr. Jerry Mitrovica @31:14 of the video in that post).

The bathtub model is actually a cultural myth that damages comprehensive understanding of the real nature of sea level change (SLC).

Fig. 1

It is a meme bandied about by both those with and those without a substantial scientific foundation.

It is even bandied about by those who should understand it better (William L. Chameides is Dean of Duke University’s Nicholas School of the Environment).

That member of the warming commentariat, like way too many others, has yet to learn that gravity has a major part to play (The Gravity of Sea Level Change, 2, 3, 4).

Fig. 2

Or that a substantial but little known portion of SLC is sea level fall (SLF), which is caused by the loss of gravity when global warming melts ice sheets from above or from below (The Ghost-Water Constant, 2, 3, 4, 5, 6, 7).

That phenomenon has yet to be perfectly quantified even though it is a major player in SLC.

Anyway, I have been demonstrating the absurdity of the bath tub model by publishing graphs of Dredd Blog Zones (see Fig. A at the top-left of this post).

Those zones are very small areas (compared to the entire globe) where one can focus on the various and sundry differences of SLC by observing tide gauge station records.

Fig. 3

Recently, regular readers and I have been looking at 21 of those zones in terms of their basic structure.

That basic structure is individual tide gauge station records within those zones, but more than that, I used records begun in the 1800s.

Those 21 zones were presented in a recent post in that format, which looks like an explosion in a spaghetti factory.

So, today I have presented graphs of those 21 zones in a mean average presentation,

Fig. 4

rather than in the spaghetti code mode.

Regular readers can thereby see how global mean average glosses over the wild dynamics of actual reality SLC in global mean average scenarios.

Compare the following 21 zones that are presented in mean average mode with those 21 zones in single tide gauge records mode (yesterday's post is On The Natural Variability of Tide Gauge Records):

Fig. 1) Zone: AD.SW.SE, 38 stations, begin year: 1858

Fig. 2) Zone: AG.NE.SE, 31 stations, begin year: 1899

Fig. 5

Fig. 3) Zone: AG.SE.NE, 11 stations, begin year: 1855

Fig. 4) Zone: AH.NE.SE, 36 stations, begin year: 1897

Fig. 5) Zone: AH.SE.NE, 31 stations, begin year: 1856

Fig. 6) Zone: AH.SE.SW, 29 stations, begin year: 1898

Fig. 7) Zone: AI.NE.NE, 35 stations, begin year: 1858

Fig. 8) Zone: AI.NE.SE, 32 stations, begin year: 1807

Fig. 6

Fig. 9) Zone: AI.SE.NE, 29 stations, begin year: 1882

Fig. 10) Zone: AI.SE.SE, 20 stations, begin year: 1881

Fig. 11) Zone: AJ.NW.NW, 54 stations, begin year: 1811

Fig. 12) Zone: AJ.NW.NE, 29 stations, begin year: 1858

Fig. 13) Zone: AJ.NW.SW, 33 stations, begin year: 1833

Fig. 14) Zone: AJ.SW.NW, 38 stations, begin year: 1884

Fig. 15) Zone: AJ.SE.NW, 6 stations, begin year: 1874

Fig. 7

Fig. 16) Zone: AL.SW.SW, 71 stations, begin year: 1894

Fig. 17) Zone: AQ.NW.NE, 3 stations, begin year: 1882

Fig. 18) Zone: AQ.NW.SW, 8 stations, begin year: 1878

Fig. 19) Zone: AQ.NW.SE, 9 stations, begin year: 1882

Fig. 20) Zone: A2.NE.NE, 4 stations, begin year: 1897

Fig. 21) Zone: A3.NE.NW, 10 stations, begin year: 1886

Each of those zones is represented in today's graphs, in terms of RLR mm, with a single

Fig. 8

graph line, and the actual SLC in millimeters is also a single graph line.

Yesterday's graphs of the same zones have one line for each tide gauge station SLC history in the particular zone being graphed.

In today's post, each tide gauge station's record is averaged into a zone mean average line, rather than having up to 71 lines for one graph.

The split frame view in today's graphs are the same mean average, it is just that the top line is a PSMSL RLR mm value, while the lower one is the actual SLC in millimeters, of the upper PSMSL RLR value line.

In other words, the subtraction has been done for you.

When an area is small like this, zone mean average is not as destructive to the understanding of what is going on as it is when the entire globe of the Earth is averaged into one value..

The remaining graphs:

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Fig. 9

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Fig. 14

Fig. 15

Fig. 16

Fig. 17

Fig. 18

Fig. 19

Fig. 20

Fig. 21

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

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