Acceleration of Sea Level Change (SLC) at individual tide gauge stations is like SLC in general, it varies from stations at one seacoast compared to stations at another seacoast, depending on location differences.
The decadal average acceleration of a large group of such tide gauge stations around the globe is shown in Fig. 1.
The average SLC itself in PSMSLRLR values and the quantity of SLC in millimeters, at those same tide gauge stations, is shown in Fig. 2.
Fig. 2 RLR and SLC values
In the previous post of this series the individual tide gauge station RLR values were shown in the following appendices (GAUGES A-D, GAUGES E-H, GAUGES I-L, GAUGES M-P, GAUGES Q-S, GAUGES T-Z; Note that the coastline code numbers mentioned in those appendices are PSMSL coastline codes listed on the PSMSL website here).
All the stations in any one coastline code are averaged and listed in the appendices by the first letter in the name of each country the stations are located in (for example "United States" values would be listed in Appendix T-Z).
The first question to ask about "how much SLR?" is: "at what location?".
That is because, as we have learned over the years, there is both SLR (sea level rise) and SLF (sea level fall).
So the new acronym has been SLC (sea level change) for some time.
Thus, acceleration can apply to both SLR, SLF, and SLC.
You may hear SLC expressed as "sea level fall is increasing each year around here" (in the blue areas) or "sea level rise is increasing around here" (in the yellow and orange areas).
For example, in Juneau, Alaska the question is "how much SLF" but in the state of Florida the question is "how much SLR"; thus, the question that applies to both is "how much SLC" is taking place ("acceleration" applies to all of them that way).
A scientist who was recently voted into the The National Academy of Sciences has spoken of sea level change in the sense of mystery among the bathtub model group, concerning the SLC data generated:
"If you go all over the world sea level is rising, some places it's falling ... I'm just going to take a very select group of tide gauge records compiled by a guy named Bruce Douglas. He's very careful in looking at sites away from cities. You look at tide gauges near cities where groundwater pumping is altering, it's causing the cities to subside; you don't want to have tide gauges near places when one plate is descending under another; and you need more than 10 or 20 or 30 years of data. One of the speakers talked about this. There are strong decadal fluctuations in this data. To get a 20th century trend you need tide gauges which have at least 30 years of data. And he came up with this compilation. Now i'm going to show you. This is the sea-level rate in millimeters per year at these 24 tide gauges that are thought to be the really important gold standard tide gauges in this research. In most of my research i use hundreds of tide gauges, but i was forced to use these by reviewers. So let's look at these. These aren't grouped in any significant way these are European tide gauges, New Zealand, U.S. West Coast, South America. So I just put them together. Then you take the average and you publish your paper. In this case the average is about one and a half millimeters per year. You notice a trend that's been noticed for decades which is that European tide gauges indicate that sea level in Europe was rising at lower than the global average over the 20th century no matter what selection of tide gauge data you use. You see the same observation and in fact that's given a name in the literature. This is called the European problem, right? So nobody had a clue what was causing that."
(See video below). On another front, a recent paper conflates land surface level change with sea level surface change:
"The Greenland Ice Sheet will significantly contribute to global mean sea-level rise this century. However, glacial isostatic adjustment is expected to cause regional sea-level fall around Greenland as the land rebounds and the gravitational pull of the shrinking ice sheet decreases."
(Sea Levels Are Rising—But in Greenland, They Will Fall, emphasis added). This is an incorrect conflation of land-level-rise with sea-level-fall because all that will change by glacial isostatic adjustment itself is the high-tide and low-tide marks on the beaches of the coastline when the land rises or falls but the actual sea level remains the same.
That is, "glacial isostatic adjustment" does not "cause regional sea-level fall" even though it can change where the high tide mark is located.
This conflation happens when the same base position is not used for both measurements, which said base position can be the center of the Earth, or some same location below or above each of the two surface levels being compared.
The bottom line is that a fixed reference beginning point must be established for both the sea surface level and the tide gauge station beach area land level at the beginning of any research as to which level value in each one has changed or not changed over a span of time.
If Sea Level Rise is Accelerating (NASA) and Greenland isostatic adjustment is causing it Greenland would be dropping further and further under the sea at an accelerating rate (the high tide mark would be climbing up the beach at an accelerating rate, but the actual sea level would not be changing).
Today's appendices detail tide gauge station measurements at "tide gauges that are thought to be the really important gold standard tide gauges" (Golden Gauges) as well as many more tide gauge station data at other locations (GAUGES A-D, GAUGES E-H, GAUGES I-L, GAUGES M-P, GAUGES Q-S, GAUGES T-Z; Note that the coastline code numbers mentioned in these appendices are PSMSL coastline codes listed here).
The next post in this series is here, the previous post in this series is here.
Member of Academy of Sciences Dr. Jerry Mitrovica:
Shorter video:
at ~31:14: "By taking the [global] average you're assuming something, and you're assuming it implicitly. You're assuming what we call the bathtub model." - Dr. Mitrovica
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