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Geophysicists employ novel method to identify sources of global sea level rise

Date:
April 24, 2012
Source:
University of Toronto
Summary:
As the Earth's climate warms, a melting ice sheet produces a distinct pattern of sea level change known as its sea level fingerprint. Now, geophysicists have found a way to identify the sea level fingerprint left by a particular ice sheet, and possibly enable a more precise estimate of its impact on global sea levels.
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Shrinking Antarctic ice sheet. Each sheet of melting ice produces a distinct pattern of sea-level change.
Credit: Ben Holt Sr. (South Pasadena, CA), GRACE team, DLR, NASA

Researchers from the University of Toronto, Harvard and Rutgers Universities have found a way to identify the "sea level fingerprint" left by a particular sheet of ice -- and possibly enable a more precise estimate of its impact on global sea levels.

As Earth's climate warms, a melting ice sheet produces a distinct and highly non-uniform pattern of sea-level change, with sea level falling close to the melting ice sheet and rising progressively farther away. The pattern for each ice sheet is unique and is known as its sea level fingerprint.

"Our findings provide a new method to distinguish sea-level fingerprints in historical records of sea levels, from other processes such as ocean waves, tides, changes in ocean circulation, and thermal expansion of the ocean," said Carling Hay, a Ph D candidate in the Department of Physics at U of T and lead author of a study published in Proceedings of the National Academy of Sciences (PNAS).

"It may indeed allow us to estimate the contributions of individual ice sheets to rising global sea levels."

Scientists around the world are trying to estimate both the current rate of sea level rise and the rates of ice sheet melting, and yet little work has been done to combine the two problems and answer these questions simultaneously.

Hay and colleagues Jerry Mitrovica and Eric Morow of Harvard University and Robert E. Kopp of Rutgers University sought out statistical techniques that had not previously been applied to this problem, and began developing the new method using data analysis techniques common in other fields such as engineering science, economics, and meteorology. The researchers then tested and refined the method by applying it to synthetic data sets -- i.e., data sets with the same amount of noise as real data, but with known melting signals. The tests provide important guidance for the application of the method to actual sea-level records.

"We are now applying our methodology to historical sea level records to provide a new estimate of total sea level rise and the melt rates of the Greenland and West Antarctic ice sheets, over the 20th century," said Hay. "Preliminary results show intriguing evidence for acceleration of globally averaged sea-level rise in the second half of the period, along with a simultaneous rise in temperature. Once our study of historical records is complete, the next step will be to incorporate satellite-based measurements of sea-level changes."


Story Source:

The above post is reprinted from materials provided by University of Toronto. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. C. Hay, E. Morrow, R. E. Kopp, J. X. Mitrovica. Fostering Advance in Interdisciplinary Climate Science Sackler Colloquium: Estimating the sources of global sea level rise with data assimilation techniques. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1117683109

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University of Toronto. "Geophysicists employ novel method to identify sources of global sea level rise." ScienceDaily. ScienceDaily, 24 April 2012. <www.sciencedaily.com/releases/2012/04/120424142259.htm>.
University of Toronto. (2012, April 24). Geophysicists employ novel method to identify sources of global sea level rise. ScienceDaily. Retrieved September 2, 2015 from www.sciencedaily.com/releases/2012/04/120424142259.htm
University of Toronto. "Geophysicists employ novel method to identify sources of global sea level rise." ScienceDaily. www.sciencedaily.com/releases/2012/04/120424142259.htm (accessed September 2, 2015).

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