Canopy and physiological controls of GPP during drought and heat wave

Yao Zhang, Xiangming Xiao, Sha Zhou, Philippe Ciais, Heather McCarthy, Yiqi Luo

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


Vegetation indices (VIs) derived from satellite reflectance measurements are often used as proxies of canopy activity to evaluate the impacts of drought and heat wave on gross primary production (GPP) through production efficiency models. However, GPP is also regulated by physiological processes that cannot be directly detected using reflectance measurements. This study analyzes the co-limitation of canopy and plant physiology (represented by VIs and climate anomalies, respectively) on GPP during the 2003 European summer drought and heat wave for 15 Euroflux sites. During the entire drought period, spatial pattern of GPP anomalies can be quantified by relative changes in VIs. We also find that GPP sensitivity to relative canopy changes is higher for nonforest ecosystems (1.81 ± 0.32%GPP/%enhanced vegetation index), while GPP sensitivity to physiological changes is higher for forest ecosystems (-0.18 ± 0.05 g C m-2 d-1/hPa). A conceptual model is further built to better illustrate the canopy and physiological controls on GPP during drought periods.

Original languageEnglish (US)
Pages (from-to)3325-3333
Number of pages9
JournalGeophysical Research Letters
Issue number7
StatePublished - Apr 16 2016
Externally publishedYes


  • anomaly
  • land surface temperature
  • production efficiency models
  • vapor pressure deficit
  • vegetation indices

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences


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