Wednesday, November 25, 2015

Watch The Ice Shelves

Fig. 1 Wilmington, NC
I. Background

This year I have focused on ice shelves in several posts.

Some of those Dredd Blog posts discussed a controversy concerning the impact of sea level fall (SLF) on ice shelves when that SLF is caused by one particular type of action, which is ice sheet mass / gravity loss.

Ice sheet mass / gravity loss is known to cause an ongoing decrease in sea level, at
Fig. 2 Low / High Mean Sea Level
and near the coast of the land mass upon which that ice sheet rests.

That would, at the same time, be a cause of ongoing decrease in the sea level upon which the ice shelf floats, thus, the argument arises that SLF, combined with daily tidal ebb and flow, puts inordinate amounts of upward then downward pressure on ice shelves attached to the ice sheets.

Fig. 3 Patterns of GMSL & GMST
Which inexorably leads to the eventual demise of the ice shelf (e.g. Peak Sea Level - 3, Peak Sea Level - 5).

We have the example of an actual and quite recent ice shelf collapse, the Zachariae Isstrom, in N.E. Greenland where SLF is an ongoing phenomenon as it is in other such areas (Peak Sea Level - 6), Proof of Concept - 3, 5).

As Dr. Eric Rignot explained, as goes the ice shelf so goes the ice stream flow in the ice sheet (which that ice shelf is holding back or slowing down).

II. An Interesting Source of Egress & Ingress

Regular Dredd Blog reader, Tom, came upon an interesting video (first video below)
Fig. 4  The Great Divide
which depicts dynamic sub-surface processes that carry away massive quantities of colder, dense water from the coastal areas of the continent of Antarctica.

That fluid dynamic is similar to others that carry warmer water under the ice shelves --all of which are contributing to the thinning of the ice shelves (second video below), and thereby helping to speed up of the flow of the hundreds or thousands of ice streams in Antarctica and Greenland ice sheets.

III. The Local and Global Pictures Give The Same Narrative

Once again, I have prepared some graphs to show how important it is to keep in mind the difference between local sea level rise (SLR) and global SLR.

The same holds true for SLF.

Fig. 5  Global Temperature Pattern
For example, there is no global SLF, as generated by ice sheet gravity loss, but there is the mathematical concept of global SLR.

If you will take note of Fig. 1, the issue may become more clear.

On that graph, generated by Dredd Blog software modules, the actual history of sea level at Wilmington is depicted in terms of RLR sea level at tide gauge stations around the globe (see PSMSL).

The herky jerky line on the graph is the actual sea level history at that local tide gauge
Fig. 6  All Together
station, while the smoother lines are the actual patterns of  global mean sea levels and global mean surface temperatures.

They are fused into one graph by the software which identifies and collects their patterns, then conforms those collected patterns into the graph space, so that the non-local patterns can be viewed realistically, along with the actual local SLR patterns of both the IPCC (2013) future expectations, as well as the Hansen (2015) expectations.

You can then easily see that Wilmington is above the global mean sea level (GMSL) as well as the pattern of global mean surface temperature (GMST), etc.

In Fig. 6 you can see how those patterns look when normalized with IPCC 5th Assessment (2013) and Hansen (2015) projections.

The local sea level is shown, along with both global mean sea level and global mean surface temperature as needed, to depict relevant historical and future relationship patterns.

IV. Conclusion

As fall and winter now comes to Greenland, spring and summer are coming to Antarctica.

The demise of the ice shelves and ice sheets will proceed.

Local sea levels will continue to rise, the scientists will continue to calculate the mathematical global mean sea level rise, warming at the poles will continue to increase at a rate much higher that at the middle portions of the globe.

The counter-invasion of current civilization is well under way (Greenland & Antarctica Invade The United States, 2, 3, 4, The 1% May Face The Wrath of Sea Level Rise First, Why The Military Can't Defend Against The Invasion, Weekend Rebel Science Excursion - 44).

That invasion will give new meaning to "The Hundred Years War."

The next post in this series is here.

A discussion about ice shelves vs. ice sheets:

15:29 when the ice shelf "Larsen A" collapsed the entire glacier's flow speed toward the sea increased ...
18:50 "Larsen B" ice shelf collapse caused the same thing ... the entire glacier's flow accelerated toward the sea ...
19:30 when the ice shelf goes away so does the restraint on the glacier, and they then move faster, 8 times faster, toward the sea
27:15 the East Antarctica Totten Glacier basin contains about as much ice as all of Western Antarctica, and it is destabilizing
30:30 the condition of the ice shelf controls what happens to the ice sheet

1 comment:

  1. Attaway Dredd! Happy Thanksgiving [in your heart, not the mass slaughter of turkeys]!