Ecological Archives M074-011-A3

Mark W. Denny, Brian Helmunth, George H. Leonard, Christopher D. G. Harley, Luke J. H. Hunt, and Elizabeth K. Nelson. 2004. Quantifying scale in ecology: lessons from a wave-swept shore. Ecological Monographs 74:513–532.

Appendix C. Autocorrelation.

The autocorrelation function is a measure of how well points in a series of data are correlated to other points in the same series, separated by a certain lag. Consider a set of n measurements, x1, x2, ... xn, taken at equal intervals in either time or space. The autocovariance for a lag, r, is

(C.1)

 

where x is the mean of the data series.

The autocovariance can be expressed as a fraction of the overall variance to give the autocorrelation:

(C.2)

 



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