The method of empirical orthogonal functions (EOFs) is used to analyse
spatio-temporal data obtained from simulations of heterogeneous catal
ysis. It is found that EOFs are well suited for the quantitative deter
mination of transients in the data. The effectivity of the technique i
s demonstrated using synthetical data with an analytically known trans
ient component. (C) 1997 Elsevier Science Ltd.