Friday, September 23, 2022

Ups And Downs Of SLC

Sea level conundrums

Today's graphs show both the ups and downs of sea level change because that is closer to the scientific reality.

Unlike many of the descriptions of sea level change that use frivolous descriptions, the seriousness of sea level change becomes more real with specificity.

For example, "The Warming Science Commentariat" likes to use expressions such as "1.5 mm per year".

This fuzzy granularity they use is typically applied to the entire ocean, as if sea level change is like a bathtub with a universal "behavioral" pattern.

But they don't like to mention specifically where that change is happening, for how long that has been happening, or whether that change in sea level is a "fall" or a "rise".

Nevertheless, many tide gauge stations (documented at PSMSL) have in the past, and may at one time in their future experience sea level that is predominantly rising, but at another time they may experience sea level that is predominantly falling.

This especially applies to tide gauge stations within about two thousand kilometers of a Cryosphere location (e.g. Greenland, Antarctica, The Third Pole) as Dr. Mitrovica has pointed out ad nausem (see e.g. video below and Seaports With Sea Level Change - 20).

This has been a regular feature of Dredd Blog posts for years (see the "SEA LEVEL CHANGE" section on the "Series Posts (N-Z)" tab at the top of the blog page).


The graphs in today's appendices clearly show the rise and fall of sea level at various times at various tide gauge stations around the world (Appendix Links: A-C, D-G, H-O, P-T, U-Z).

An arbitrary time frame of 1800-2050 is utilized (actual measurements at tide gauge stations is sandwiched between the estimated past and estimated future of each location's in situ measurement records).

An important "take-home" from this is that accumulated sea level rise is brought into a more accurate understanding when we know how much time is involved in the "it has risen or fallen this much" figures.

The graphs in the appendices indicate how much change has taken place in three segments of time (before measurements, during measurements, and projected future amounts).

The time before a tide gauge station began recording changes in sea level, as well as the time following its most recent recorded changes, are calculated using the actual measured values records.

These before calculations and future calculations are "educated guesstimates", and are represented by different colored lines.

The before-recordings-of-change line is blue, the time-of-recordings line is green, and the estimated-future-change line is brown.

The "station number" is the PSMSL station number (lookup station info here); the "Zone" number is the WOD zone number; lookup zone number location info here).

Total change amounts in millimeters, feet, and/or inches are tallied (Note: in large mm change scenarios the upper left corner of the graph has an "(x103)" designation which means that the graph's millimeter values are in thousands).

Hopefully this gives a better picture and better concept of reality than the "1.5 mm per year" estimates that "the warming science commentariat" gives us.

UPDATE: I updated the graphs. The left side of the graphs which indicated "millimeters" had erroneous values. 

I have replaced them with "RLR millimeters" which is what the PSMSL uses (Revised Local Reference [RLR] Definition).

I have ordered the graphs by PSMSL Station Id so you can look them up here more easily.

Any that did not have at least 75 years of data were removed (guesstimates for "before measurements began" and "after measurements ended" are more accurate with an extended number of years to calculate with).

If Dredd Blog was a whale:

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