Categorization of land‐cover change processes based on phenological indicators extracted from time series of vegetation index data

Abstract

A straightforward method for categorizing temporal patterns of land‐cover change is presented. Two successive years of enhanced vegetation index (EVI) data derived from the Moderate Resolution Imagery Spectrometer (MODIS) were analysed. Five phenological indicators were extracted. Based on the inter‐annual difference of each of the five indicators, indices of change in phenology were calculated. An unsupervised classification of these five indices of change applied to pixels characterized by a high change magnitude led to the identification of seven categories of land‐cover change patterns. Thirty‐one per cent of the change pixels could clearly be explained by a difference in only one or two phenological indicators, e.g. a shift in the start of the growing season or an interruption of the growing season due to floods. The remaining change pixels were explained by a combination of more than two indices of change. The output of this analysis is an allocation of change pixels to broad categories of land‐cover change as a preliminary step for finer resolution analyses.

Acknowledgements

This study was conducted within the framework of the GLOVEG Program, funded by the Belgian Science Policy Office, under contract VG/00/01 by the Belgian Ministry of Science. The authors wish to thank S. Flasse for valuable suggestions and comments offered during the preparation of this paper. We would like to thank Boston University's MODIS Land Cover Group for the provision of MODIS data.