Correspondence: Space-time asymmetry undermines water yield assessment.

Wouter R Berghuijs,Ross A Woods

doi:10.1038/ncomms11603

Abstract

Correspondence: Space-time asymmetry undermines water yield assessment.

Highlights

Understanding the effects of climate and land-cover changes on water yield is a challenging component in assessments of future water resources
Zhou et al.1 use Fuh’s equation2, based on the widely used Budyko framework3, to quantify the spatial differences of mean water yield normalized by precipitation (R/P) as a function of the climate wetness index and watershed characteristics (m)
Zhou et al.1 analyse how three variables (R/P, P/PET, m) co-vary in space, to approximate their behaviour in time, and thereby implicitly assume that there is symmetry between spatial and temporal partitioning of precipitation into streamflow and evaporation. This is not necessarily the case for watersheds5. To test if this symmetry assumption is valid we compare qR/P/qP/PET, as approximated by the Zhou et al.1 equation, and the qR/P/qP/PET calculated using inter-annual water balances

Summary

Introduction

Understanding the effects of climate and land-cover changes on water yield is a challenging component in assessments of future water resources. Zhou et al.1 use Fuh’s equation2, based on the widely used Budyko framework3, to quantify the spatial differences of mean water yield normalized by precipitation (R/P) as a function of the climate wetness index (precipitation/potential evaporation P/PET) and watershed characteristics (m). Similar to what has been done before4, Zhou et al.1 subsequently derive the sensitivity of R/P to both wetness (qR/P/qP/PET) and watershed characteristics (qR/P/qm) to expose the role of climatic and land-use changes on water yield.

Results

Conclusion