ESS210B
Prof. Jin-Yi Yu
Composite
Analysis
qCompositing analysis
(also called superposed epoch analysis) is to sort time
series into different categories (or phases) and to compare means in these
categories.
qFor example, how do
Pacific SST evolve before, during, and after an El Nino event? In this
case, there are three categories (before, during, and after) in the
composite analysis.
qCompositing is useful
when you have many observations of some event and you are
looking for responses to that event that are combined with noise from a lot
of other influences.
qThe basic idea of the
compositing analysis is that the averaging process will remove noise and
keep the signals of interest.
qOften compositing will
reveal periodic phenomena with fixed phase that
cannot be extracted from spectral analysis if the signal is small compared to the
noise.