Articles | Volume 21, issue 1
Hydrol. Earth Syst. Sci., 21, 217–233, 2017
https://doi.org/10.5194/hess-21-217-2017
Hydrol. Earth Syst. Sci., 21, 217–233, 2017
https://doi.org/10.5194/hess-21-217-2017

Research article 11 Jan 2017

Research article | 11 Jan 2017

A Budyko framework for estimating how spatial heterogeneity and lateral moisture redistribution affect average evapotranspiration rates as seen from the atmosphere

Elham Rouholahnejad Freund and James W. Kirchner

Data sets

Hole-filled SRTM for the globe Version 4, available from the CGIAR-CSI SRTM 90m Database A. Jarvis, H. I. Reuter, A. Nelson, and E. Guevara http://www.cgiar-csi.org/data/srtm-90m-digital-elevation-database-v4-1

MODIS Global Evapotranspiration Project (MOD16) Numerical Terradynamic Simulation Group http://www.ntsg.umt.edu/project/mod16

WorldClim 1.4: Current conditions (~1960-1990) WorldClim - Global Climate Data http://www.worldclim.org/current

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Short summary
Our analysis shows that averaging over sub-grid heterogeneity in precipitation and potential evapotranspiration (ET), as typical earth system models do, overestimates the average of the spatially variable ET. We also show when aridity index increases with altitude, lateral redistribution would transfer water from more humid uplands to more arid lowlands, resulting in a net increase in ET. Therefore, the Earth system models that neglect lateral transfer underestimate ET in those regions.