Wednesday, August 15, 2018

Build Your Own Sea Level Change Fingerprinting System - 2

Fig. 1 Origin of Graphic (PDF)
Today let's analyze WOD Zone 7307 and WOD Zone 7407.

And let's do that analysis in the same manner that we analyzed WOD Zone 1313 and WOD Zone 1314 in the previous post of this series (Build Your Own Sea Level Change Fingerprinting System).

We will use the graphic at Fig. 1 in the same manner that we did in the previous post (ibid).

Interestingly, the context is practically the same in the sense that there is a large red area which indicates a comparatively high sea level rise impact from West Antarctica, as there was in the previous post (ibid).

Fig. 2
Also interesting is that the ice sheet impact reverses, that is, West Antarctica is the main impactor in the zones analyzed in this post, whereas Greenland was the main impactor in the previous post (ibid).

One thing that makes it even more interesting is that WOD Zone 7307 and WOD Zone 7407 are closer to Greenland than the zones in the previous post were (especially Zone 7407).

Fig. 3a
Fig. 3b
Moving along, remember as was stated in the previous post, that the first step in the process is to weed out obviously bad data.

The graphs at Fig. 3a and Fig. 3b show that there was an aberration in the data of one of these two zones, as there was in the previous post, which we must correct first before we proceed.

The problem in Zone 7407 was corrected by removing the latest year (yr 2017) which had incorrect or incomplete tide gauge data.

So, on to the graphs.

The pattern in Zone 7307 (Fig. 2) is more uniform and proportional than Zone 7407 (Fig. 3a) to the south of it because the high and low value lines follow an almost synchronous upward trend pattern.

I attribute that to consistent, evenly matched Greenland and West Antarctica impact, with West Antarctica producing the high sea level effect (black line), and Greenland mitigating it fairly evenly as shown by the low sea level effect (red line).

If you notice the left side of Fig. 1, which pertains to Greenland, some of the sea level fall reaches near or even into Zone 7407, which can be attributed to the uneven impact shown by the low value line (red line) on the graph at Fig. 3a (the two lines move away from one another rather than following an even pattern like Zone 7307 lines do).

Nevertheless, the Zone 7407 high value line (black line)  continues upward as does the Zone 7307 black line, which can be attributed to West Antarctica impact on both of them.

That is because both zones are in the high impact sea level rise red zone shown on the right side of the Fig. 1 graphic.

The uneven decrease in the red line in Zone 7407, in contrast to the increase in the black line, is because Zone 7407 is closer to Greenland than Zone 7304 is.

Therefore Zone 7407 is more subject to impacts of sea level fall influences as Greenland loses its gravitational influence that pulls seawater towards it.

To the contrary, the consistent pattern in the red and black lines in Zone 7307 is due to its being further from Greenland, so the pattern has more of the likeness of the predominant West Antarctica impact.

Four zones done, six to go.

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

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