Paper Review: Samuels-Crow (2020). SAM->NEE and ET. JGRBG

· ☕ 2 min read · ✍️ Hoontaek Lee

23 July, 2020 (Samuels-Crow, JGRBG, SAM->NEE and ET)

Samuels‐Crow, K. E., Ogle, K., & Litvak, M. E. (2020). Atmosphere‐Soil Interactions Govern Ecosystem Flux Sensitivity to Environmental Conditions in Semiarid Woody Ecosystems over Varying Timescales. Journal of Geophysical Research: Biogeosciences, 125, e2019JG005554.


Samuels-Crow et al., in this paper, quantified environmental antecedent (past) memory of water (ET) and carbon (NEE) fluxes over two semi-arid sites where two different conifer species dominate each. They used flux datasets from a network of eddy covariance towers (i.e. Ameriflux), relevant environmental observations, and a hierarchical Bayesian framework (i.e. the SAM framework). In general, the results showed that NEE and ET negatively, and instantaneously, responded to changes in air temperature and VPD. Conversely, NEE and ET showed positive, and with longer temporal timescale, relationship with precipitation and soil moisture at deeper level. The authors reminded that the timescale of the environmental memory on NEE was highly variable with a longer scale for arid area. However, although they speculated the reason, it seems that the behind mechanism is remained unexplained.

Questions unexplained

  • Why the timescales over which soil moisture and precipitation influence NEE are highly variable in forested ecosystems?

  • Why drier ecosystems show longer timescale of environmental memory on NEE?

  • Knowledge about the plant ecophysiology may be a key to answer the question above.

  • Answering those questions would be improve our understanding of water and carbon cycles.


  • I felt that the describing style was meticulous and detailed. Not only from this paper but from other papers of the Ogle Lab. such as Liu et al. (2019) I felt the same thing. From which point did I feel like that?
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Hoontaek Lee
Hoontaek Lee
Tree-Forest-Climate Researcher

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