Preprints
https://doi.org/10.5194/egusphere-2025-5684
https://doi.org/10.5194/egusphere-2025-5684
21 Nov 2025
 | 21 Nov 2025

Improved model predictions of carbon and water fluxes by including drought legacy effects

Yitong Yao, Yujie Wang, Yi Yin, Jeffrey D. Wood, and Christian Frankenberg

Abstract. Besides simultaneous influences, droughts have lasting impacts on vegetation by impairing hydraulic and photosynthetic capacities, known as the drought legacy effects. The ignorance of legacy effects in numerical simulations, such as lagged xylem recovery, may lead to significant model-observation discrepancies. However, the limited temporal resolution of most observational data makes it challenging to capture the physiological dynamics necessary to improve model accuracy. Here, we investigated the recovery of carbon flux (represented by gross primary productivity, GPP) and water flux (represented by evapotranspiration, ET) following a severe drought in 2012, using half-hourly eddy-covariance flux observations and weekly predawn leaf water potential measurements from a temperate forest in the Central US. We implemented both optimality-based and empirical stomatal models within a land surface model, testing three drought recovery scenarios for each: no recovery, full recovery, and partial recovery of xylem hydraulic conductance and photosynthetic capacity. Before and during the drought, all stomatal models performed similarly for GPP and ET. Post-drought, assuming no recovery led to underestimated ET; assuming full recovery led to overestimated GPP; and assuming partial recovery improved both, indicating persistent biochemical limitations after drought. The observed carbon-water decoupling during and after the event further points to non-stomatal constraints on photosynthesis and unequal stress on carbon and water fluxes. Our work highlights the need to account for delayed recovery of xylem hydraulics and photosynthetic capacity when modeling drought legacy effects. Further research to mechanistically represent dynamic recovery processes, particularly their timing and magnitude, is essential for improving the modeling of global carbon and water fluxes.

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Journal article(s) based on this preprint

07 Aug 2026
Improved model predictions of carbon and water fluxes by including drought legacy effects
Yitong Yao, Yujie Wang, Yi Yin, Jeffrey D. Wood, and Christian Frankenberg
Biogeosciences, 23, 5461–5475, https://doi.org/10.5194/bg-23-5461-2026,https://doi.org/10.5194/bg-23-5461-2026, 2026
Short summary
Yitong Yao, Yujie Wang, Yi Yin, Jeffrey D. Wood, and Christian Frankenberg

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-5684', Anonymous Referee #1, 18 Dec 2025
    • AC1: 'Reply on RC1', Yitong Yao, 13 Feb 2026
  • RC2: 'Comment on egusphere-2025-5684', Xin Yu, 05 Jan 2026
    • AC2: 'Reply on RC2', Yitong Yao, 13 Feb 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
ED: Reconsider after major revisions (01 Apr 2026) by Mirco Migliavacca
AR by Yitong Yao on behalf of the Authors (24 Apr 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (08 Jun 2026) by Mirco Migliavacca
RR by Xin Yu (15 Jun 2026)
RR by Anonymous Referee #1 (03 Jul 2026)
ED: Publish subject to minor revisions (review by editor) (28 Jul 2026) by Mirco Migliavacca
AR by Yitong Yao on behalf of the Authors (29 Jul 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (29 Jul 2026) by Mirco Migliavacca
AR by Yitong Yao on behalf of the Authors (31 Jul 2026)

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-5684', Anonymous Referee #1, 18 Dec 2025
    • AC1: 'Reply on RC1', Yitong Yao, 13 Feb 2026
  • RC2: 'Comment on egusphere-2025-5684', Xin Yu, 05 Jan 2026
    • AC2: 'Reply on RC2', Yitong Yao, 13 Feb 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
ED: Reconsider after major revisions (01 Apr 2026) by Mirco Migliavacca
AR by Yitong Yao on behalf of the Authors (24 Apr 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (08 Jun 2026) by Mirco Migliavacca
RR by Xin Yu (15 Jun 2026)
RR by Anonymous Referee #1 (03 Jul 2026)
ED: Publish subject to minor revisions (review by editor) (28 Jul 2026) by Mirco Migliavacca
AR by Yitong Yao on behalf of the Authors (29 Jul 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (29 Jul 2026) by Mirco Migliavacca
AR by Yitong Yao on behalf of the Authors (31 Jul 2026)

Journal article(s) based on this preprint

07 Aug 2026
Improved model predictions of carbon and water fluxes by including drought legacy effects
Yitong Yao, Yujie Wang, Yi Yin, Jeffrey D. Wood, and Christian Frankenberg
Biogeosciences, 23, 5461–5475, https://doi.org/10.5194/bg-23-5461-2026,https://doi.org/10.5194/bg-23-5461-2026, 2026
Short summary
Yitong Yao, Yujie Wang, Yi Yin, Jeffrey D. Wood, and Christian Frankenberg
Yitong Yao, Yujie Wang, Yi Yin, Jeffrey D. Wood, and Christian Frankenberg

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Short summary
Droughts can leave lasting "scars" that slow down recovery long after the rain returns. In this study, we found that models assuming plants recover immediately after drought performed poorly, while those allowing only partial recovery matched real observations much better. Accounting for these delayed recovery processes will make land surface models more accurate in predicting carbon and water cycles under future droughts.
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