A NEW QUANTITATIVE TEST OF GEOMORPHIC MODELS, APPLIED TO A MODEL OF BRAIDED STREAMS

Recent simple cellular models of self-organized geomorphic patterns em body a new understanding of complex, spatially extended systems. Such models can be difficult to test quantitatively because the statistics traditionally used can be insensitive even to visually obvious variati ons in a complex pattern. Here we develop a new approach to evaluating such models. We begin by applying to spatial patterns the state-space reconstruction techniques developed for dynamical systems, producing plots that summarize the patterns in a way that preserves more informa tion than do the statistics usually used in geomorphology. Methods exi st for characterizing some aspects of such plots. Here we develop a co mplementary method for quantitatively comparing state-space plots in a way that more directly evaluates the similarity between the typical f eatures of spatial patterns. An application of this method to the patt erns produced by a cellular braided-stream model and real braided stre ams indicates that this approach provides a relatively sensitive way o f comparing model-generated and real spatial patterns.