Quantifying Asynchronicity of Precipitation and Potential Evapotranspiration in Mediterranean Climates


Journal Article

©2019. American Geophysical Union. All Rights Reserved. Recent climate change has contributed to shifts in the seasonal interplay between precipitation and potential evapotranspiration, which have in turn increased droughts and reduced freshwater availability in Mediterranean climate regions. To overcome limitations in existing indices for comparing these seasonal hydroclimatic drivers at the global scale, we introduce an information theory-based, nonparametric asynchronicity index that captures both the temporal alignment and relative magnitudes of precipitation and potential evapotranspiration. We use this asynchronicity index to first identify Mediterranean climates around the world. We then apply the asynchronicity index over two Mediterranean climate regions and show that their boundaries have shifted between 1960 and 2018, resulting in a regional expansion in the U.S. Pacific Northwest and a contraction in southwestern Australia. These results highlight the need for globally consistent measures of seasonal climatic water supply and demand for diagnosing potential changes in water resources and ecosystem responses within Mediterranean climate regions.

Full Text

Duke Authors

Cited Authors

  • Feng, X; Thompson, SE; Woods, R; Porporato, A

Published Date

  • December 28, 2019

Published In

Volume / Issue

  • 46 / 24

Start / End Page

  • 14692 - 14701

Electronic International Standard Serial Number (EISSN)

  • 1944-8007

International Standard Serial Number (ISSN)

  • 0094-8276

Digital Object Identifier (DOI)

  • 10.1029/2019GL085653

Citation Source

  • Scopus