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

doi:10.1088/1748-9326/11/10/104012

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 journal › Article › peer-review

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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 language	English
Article number	104012
Pages (from-to)	1-10
Number of pages	10
Journal	Environmental Research Letters
Volume	11
Issue number	10
DOIs	https://doi.org/10.1088/1748-9326/11/10/104012
Publication status	Published - 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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10.1088/1748-9326/11/10/104012

Publisher version (open access)Final published version, 1.54 MBLicence: CC BY

Cite this

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

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.",

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doi = "10.1088/1748-9326/11/10/104012",

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T1 - Land surface models systematically overestimate the intensity, duration and magnitude of seasonal-scale evaporative droughts

AU - Ukkola, A. M.

AU - De Kauwe, M. G.

AU - Pitman, A. J.

AU - Best, M. J.

AU - Abramowitz, G.

AU - Haverd, V.

AU - Decker, M.

AU - Haughton, N.

N1 - 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.

PY - 2016/10/13

Y1 - 2016/10/13

N2 - 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.

AB - 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.

KW - evaporative drought

KW - evapotranspiration

KW - FLUXNET

KW - heat waves

KW - land surface models

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ER -

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

Abstract

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Identifying regions of high drought mortality risk for tree species in NSW

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

Abstract

Bibliographical note

Keywords

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Identifying regions of high drought mortality risk for tree species in NSW

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