Time filter

Source Type

Mi N.,Institute of Atmosphere Environment | Zhang Y.-S.,Institute of Atmosphere Environment | Ji R.-P.,Institute of Atmosphere Environment | Cai F.,Institute of Atmosphere Environment | And 3 more authors.
Chinese Journal of Ecology | Year: 2011

Plant leaf stomatal conductance (g) is an important factor controlling the energy and water exchanges between canopy and atmosphere, while air humidity is a key environmental variable controlling the g. In last decade, the stomatal conductance - humidity relationships in Ball- Woodrow-Berry (BWB) and Leuning models were widely used. In this study, a new diagnostic parameter f(H) was adopted to assess the response of g to air humidity. Based on the leaf-level measurements in a cropland ecosystem, the performance of the BWB, Leuning, and newly developed power-h and power-D models was examined. The results showed that the BWB model which employs a linear relationship between g and relative humidity (hs) led to a larger underestimate of g when the air was wet, while the Leuning model which employs a nonlinear function of water vapor pressure deficit (Ds) decreased this bias but still not adequately captured the significant increase of g under the wet condition. Compared with BWB and Leuning models, the newly developed power-h and power-D models that employ a power function of Ds and a power function of relative humidity deficit (1-hs), respectively, showed better performance. The results also indicated that the models based on Ds generally performed better, compared with those based on hs.

Loading Institute of Atmosphere Environment collaborators
Loading Institute of Atmosphere Environment collaborators