Sunday, October 1, 2017

NASA Busts The Ghost

Fig. 1 NASA detective work sees ghost water
It is no secret to regular readers that ghost-water has been around for a couple of centuries (The Ghost-Water Constant, 2, 3, 4, 5, 6, 7, 8, 9; Weekend Rebel Science Excursion - 54).

But, the very abundant ghost-water can only be seen by those without a pre-Newton view of science (The Gravity of Sea Level Change, 2, 3, 4); and since NASA is one of the branches of government that understands the reality of the existence of Newton, it was inevitable that they were going to get into sleuth mode sooner or later and do some ghost-busting.

Once they put on their Sherlock Holmes hat, it was also inevitable that they would detect the fingerprints of the once "very well hidden-in-plain-sight" ghost-water:
"Researchers from NASA’s Jet Propulsion Laboratory in Pasadena, California, and the University of California, Irvine, have reported the first detection of sea level “fingerprints” in ocean observations: detectable patterns of sea level variability around the world resulting from changes in water storage on Earth’s continents and in the mass of ice sheets. The results will give scientists confidence they can use these data to determine how much the sea level will rise at any point on the global ocean as a result of glacier ice melt.

As ice sheets and glaciers undergo climate-related melting, they alter Earth’s gravity field, resulting in sea level changes that aren’t uniform around the globe. For example, when a glacier loses ice mass, its gravitational attraction is reduced. Ocean waters nearby move away, causing sea level to rise faster far away from the glacier. The resulting pattern of sea level change is known as a sea level fingerprint. Certain regions, particularly in Earth’s middle and low latitudes, are hit harder, and Greenland and Antarctica contribute differently to the process. For instance, sea level rise in California and Florida generated by the melting of the Antarctic ice sheet is up to 52 percent greater than its average effect on the rest of the world.

To calculate sea level fingerprints associated with the loss of ice from glaciers and ice sheets and from changes in land water storage, the team used gravity data collected by the twin satellites of the U.S./German Gravity Recovery and Climate Experiment (GRACE) between April 2002 and October 2014. During that time, the loss of mass from land ice and from changes in land water storage increased global average sea level by about 0.07 inch (1.8 millimeters) per year, with 43 percent of the increased water mass coming from Greenland, 16 percent from Antarctica and 30 percent from mountain glaciers. The scientists then verified their calculations of sea level fingerprints using readings of ocean-bottom pressure from stations in the tropics.

“Scientists have a solid understanding of the physics of sea level fingerprints, but we’ve never had a direct detection of the phenomenon until now,” said co-author Isabella Velicogna, UCI professor of Earth system science and JPL research scientist.

“It was very exciting to observe the sea level fingerprints in the tropics, far from the glaciers and ice sheets,” said lead author Chia-Wei Hsu, a graduate student researcher at UCI.

The findings are published
[PDF] today in the journal Geophysical Research Letters. The research project was supported by UCI and NASA’s Earth Science Division."
(NASA/UCI Find Evidence of Sea Level 'Fingerprints', emphasis added). The link discusses a paper in Geophysical Research Letters.

The published paper is unambiguous and straight forward:
"As ice sheets and glaciers and ice caps melt into the ocean, the pattern of regional sea level rise is nonuniform and tracked via the sea level fingerprints. Here we provide the first observational evidence that the [fingerprints] calculated from satellite observations match the record from ocean stations that measure mass changes over time, i.e., the Gravity Recovery and Climate Experiment-based satellite technique correctly captures the distribution of freshwater fluxes to the ocean and the signal is large enough to be detected by ocean in situ observations in the tropics. The results are critical to improve regional projections of sea level rise and its impact on coastlines and human systems."
(Geophysical Research Letters). They cite two papers by Professor Mitrovica (2001 and 2009), but still have not found Woodward (1888).

The "ocean-bottom pressure" detection technique reminded me of another Dredd Blog series (Is A New Age Of Pressure Upon Us?, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13).

That series discusses sea level change as a source of contrasting torque and pressure upon the Earth's crust, which can and does lead to earthquakes and volcanic activity.

We can now hope that they will un-detect thermal expansion as "the major cause" of sea level change, because they haven't shaken that error yet:
"We calculate changes in steric [thermal expansion] height at each grid cell by vertically integrating the density profile. The vertical profiles provide data up to 2000 m depth with a vertical resolution of 10 dbar when close to the sea surface and 100 dbar close to 2000 m depth."
(ibid, Geophysical Research Letters). They can start with ceasing and desisting from scratching the surface to instead "go deep" using robust detection techniques (On The More Robust Sea Level Computation Techniques, 2, 3, 4).

The thermodynamics are seemingly still hidden in plain sight too (On Thermal Expansion & Thermal Contraction, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24).

I suggest they investigate the TEOS-10 toolkit (TEOS-10 Flyer, PDF).

Professor Jerry X. Mitrovica on the gravity / axis bulge SLR / SLF issues we don't hear about often enough:



2 comments:

  1. You were all over this WAAAAY before NASA! Great job, Dredd!

    ReplyDelete
  2. Thanks Tom, a very regular Dredd Blog reader.

    ReplyDelete