Defining and characterizing high-rainfall Mediterranean climates

Abstract

The world's five Mediterranean-climate regions are typified by similarities in climate reflected in structural vegetation patterns. We developed a methodology to define high-rainfall (annual precipitation ≥800 mm) Mediterranean climates and contrast patterns of between- and within-region climatic heterogeneity. Climatic indices describing the seasonality of the climate were computed in Geographic Information Systems and included in a numerical analysis, in addition to selected bioclimatic variables, using the pattern analysis program PATN. Selected locations from high-rainfall Mediterranean-climate regions were grouped according to climatic similarity, and within-region climatic heterogeneity was compared between regions. Areas traditionally not considered as Mediterranean-climate regions emerged in the classification. Only the Mediterranean-type systems within the Pacific north-west of North America and south-central Chile comprised a substantial extent of high-rainfall Mediterranean climate. Both of these regions were characterized by a high climatic diversity and steep topographic gradients. The numerical analysis demonstrated the high diversity of the high-rainfall Mediterranean-climate type and differences in within-region climatic heterogeneity between the world's high-rainfall Mediterranean-climate regions.

Keywords:

• Climatic classification
• climate groups
• numerical analysis
• precipitation and temperature seasonality
• within-region climatic heterogeneity

Acknowledgements

The project has been funded by an ARC International Linkage Grant (LX0775868: Biodiversity in high rainfall Mediterranean-climate ecosystems: Integrating fields of ecological enquiry to achieve conservation outcomes) to the second author. Funding for the first author has been provided from the Commonwealth Government through an Australian Postgraduate Award. Noam Levin assisted with the acquirement of climatic layers. We would also like to David Hibbs and Phil Rundel for discussions concerning high-rainfall Mediterranean ecosystems.