Land surface models systematically overestimate the intensity, duration and magnitude of seasonal-scale evaporative droughts

A. M. Ukkola*, M. G. De Kauwe, A. J. Pitman, M. J. Best, G. Abramowitz, V. Haverd, M. Decker, N. Haughton

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    71 Citations (Scopus)
    18 Downloads (Pure)

    Abstract

    Land surface models (LSMs) must accurately simulate observed energy and water fluxes during droughts in order to provide reliable estimates of future water resources. We evaluated 8 different LSMs (14 model versions) for simulating evapotranspiration (ET) during periods of evaporative drought (Edrought) across six flux tower sites. Using an empirically defined Edrought threshold (a decline in ET below the observed 15th percentile), we show that LSMs simulated 58 Edrought days per year, on average, across the six sites, ∼3 times as many as the observed 20 d. The simulated Edrought magnitude was ∼8 times greater than observed and twice as intense. Our findings point to systematic biases across LSMs when simulating water and energy fluxes under water-stressed conditions. The overestimation of key Edrought characteristics undermines our confidence in the models' capability in simulating realistic drought responses to climate change and has wider implications for phenomena sensitive to soil moisture, including heat waves.

    Original languageEnglish
    Article number104012
    Pages (from-to)1-10
    Number of pages10
    JournalEnvironmental Research Letters
    Volume11
    Issue number10
    DOIs
    Publication statusPublished - 13 Oct 2016

    Bibliographical note

    Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

    Keywords

    • evaporative drought
    • evapotranspiration
    • FLUXNET
    • heat waves
    • land surface models

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