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Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface
Published on: June 8, 2015
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When Does Vapor Pressure Deficit Drive or Reduce Evapotranspiration?
Adam Massmann1, Pierre Gentine1, Changjie Lin1,2
1Department of Earth and Environmental Engineering Columbia University New York NY USA.
Journal of Advances in Modeling Earth Systems
|January 3, 2020
Summary
Increasing vapor pressure deficit (VPD) drives atmospheric water demand. Plant responses, like stomatal closure, can either increase or decrease evapotranspiration (ET), varying by climate and plant type.
Area of Science:
- Environmental science
- Plant physiology
- Atmospheric science
Background:
- Increasing vapor pressure deficit (VPD) signifies higher atmospheric water demand.
- Plants can modulate evapotranspiration (ET) by adjusting stomatal aperture in response to VPD.
Purpose of the Study:
- To investigate whether atmospheric demand or plant physiological responses dominate ET changes with increasing VPD.
- To develop a theoretical framework for predicting ET response to VPD.
Main Methods:
- Utilized the Penman-Monteith equation.
- Integrated semiempirical optimal stomatal regulation theory.
- Incorporated water use efficiency principles to model ET response to VPD.
Main Results:
- ET response to increasing VPD is variable, ranging from decrease to increase.
- Climate (tropical/temperate vs. boreal/arctic), photosynthesis strategy (C3 vs. C4), and plant type (crops vs. shrubs/gymnosperms) significantly influence ET response.
- Tropical and temperate climates, C3 plants, and crops are more likely to show increased ET with rising VPD.
Conclusions:
- A simplified theoretical framework effectively models diverse plant water regulation strategies.
- Understanding ET response to VPD is crucial for land-atmosphere interactions.
- Plant and climate characteristics determine the direction and magnitude of ET response to VPD.
Keywords:
ecohydrologyecosystem modelingevapotranspirationland‐atmosphere interactionstomatal conductancevapor pressure deficitMore Related Videos
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