TITLE: Power spectrum of sea level change over fifteen decades of frequency
SPEAKER: Christopher Harrison
AFFILIATION: Rosenstiel School of Marine and Atmospheric Science, University of
Miami
TIME: Wed July 13, 12:30p
LOCATION: 624 Agua Fria Conference Room
Pizza will be available
ABSTRACT
The power spectrum of relative sea level change has been estimated over more
than 15 orders of magnitude in frequency, from a frequency of 1/(591 Ma) to a
frequency of 1/(5 s). Although there are still regions of the spectrum where
data sampling and duration do not allow the power to be calculated, most notably
between periods of 100?1000 years, the general shape of the spectrum is that in
which the power depends on the square of the reciprocal frequency, apart from
periods between 1 and 100 years where the power spectrum falls off less steeply
with increasing frequency. A spectrum in which power depends on reciprocal
frequency squared is the same spectrum as that calculated from a random walk
signal of finite length. There are some causes that have defined frequencies,
such as those associated with tides and the Milankovitch cycles of the ice ages,
but there is also a continuum of relative sea level change that requires other
causes. The implications of this are discussed in the light of global change and
heating of the lithosphere from the bottom.
PAPER
Harrison, C. A., (2002) Power spectrum of sea level change over fifteen decades
of frequency
http://www.friam.org/PowerSpectrumofSLChange.pdf
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