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cje ›› 2011, Vol. 30 ›› Issue (02): 389-394.

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Evaluation of stomatal conductance models based on leaf-level measurements.

MI Na, ZHANG Yu-shu**, JI Rui-peng, CAI Fu, ZHAO Xian-li, ZHANG Shu-jie, WANG Hong-bo   

  1. Institute of Atmosphere Environment, |Shenyang, China Meteorologica Administration Shenyang 110016, China
  • Online:2011-02-08 Published:2011-02-08

Abstract: 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 Dsand 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.

Key words: Soil organic carbon storage, Carbon cycle, Soil carbon cycle