Earlier Ecological Drought Detection by Involving the Interaction of Phenology and Eco‐Physiological Function
Name
Earth s Future - 2023 - Chang - Earlier Ecological Drought Detection by Involving the Interaction of Phenology and.pdf
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Published version
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3.11 MB
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Author(s)
Chang, Qing
Ficklin, Darren L
Jiao, Wenzhe
Denham, Sander O
Wood, Jeffrey D
Brunsell, Nathaniel A
Matamala, Roser
Cook, David R
Wang, Lixin
Novick, Kimberly A
Date Issued
February 27, 2023
Journal
Earth's Future
Publisher
American Geophysical Union
Citation
Chang, Q., Ficklin, D. L., Jiao, W., Denham, S. O., Wood, J. D., Brunsell, N. A., et al. (2023). Earlier ecological drought detection by involving the interaction of phenology and eco-physiological function. Earth's Future, 11, e2022EF002667.
Version
Final published version
Abstract
Meteorological drought indices like the Standardized Precipitation Evaporation Index (SPEI)
are frequently used to diagnose “ecological drought,” despite the fact that they were not explicitly designed
for this purpose. More recently developed indices like the Evaporative Stress Index (ESI), which is based
on the degree of coupling between actual to potential evapotranspiration, may better capture dynamic plant
response to moisture limitations. However, the skill of these indices at describing plant water stress is rarely
evaluated at sub-seasonal timescales over which drought evolves. Moreover, it remains unclear how variability
in phenological timing impacts and complicates early drought detection. Here, we compared the ability of
ESI and SPEI to reflect the dynamics of ecological drought in forests and grasslands, based on anomalies of
Gross Primary Productivity (GPP), surface conductance (Gs
, a proxy for stomatal conductance), soil moisture,
and vapor pressure deficit. ESI performed better than SPEI in capturing the dynamics of GPP and Gs
, but still
missed early ecological drought signals due to biases linked to earlier onset of spring leaf development. Thus,
we developed a modified variant of the ESI ( 𝐴𝐴 ESILAI) that accounts for the complicating effects of phenological
shifts in leaf area index (LAI). The 𝐴𝐴 ESILAI detected drought onset up to 7–10 weeks earlier than SPEI and ESI.
Additionally, drought onset dates determined from 𝐴𝐴 ESILAI are close to (±2 weeks) the dates determined from
LAI-corrected anomalies of Gs
, and GPP, as well as the onset dates of soil water deficit and atmospheric aridity
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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DOI of Published Version
https://doi.org/10.1029/2022ef002667
