基于夏玉米叶片气孔导度提升的冠层导度估算模型

叶片气孔导度模拟及其向冠层导度的尺度提升是实现蒸散发尺度转换的基础，对农业水资源高效利用与评价意义重大。本文依据夏玉米叶片气孔导度和冠层导度实测值，在建立叶片气孔导度估算模型基础上，构建冠层导度估算模型。结果表明，夏玉米叶片气孔导度每日在10:00－14:00之间达到峰值，其日变化趋势与光合有效辐射的一致性较好，较大的饱和水汽压差对夏玉米叶片气孔导度具有一定的限制作用。根据光合有效辐射和饱和水汽压差建立的叶片气孔导度估算模型能较好反映当地夏玉米叶片气孔导度对主要环境因子的响应过程，以光合有效辐射作为尺度转换因子构建的冠层导度估算模型可较好实现从叶片气孔导度向冠层导度的尺度转换提升。

Estimation of summer corn canopy conductance by scaling up leaf stomatal conductance

Simulation of leaf stomatal conductance (gs) and scaling it up to canopy conductance (gc) were very important for understanding the corn evapotranspiration scaling transformation. Measurements of leaf stomatal conductance (gs) and canopy conductance (gc) were made at a summer corn field. The effect of the photosynthetically active radiation (PAR) and the water vapor deficit (VPD) on gs were analyzed, and the variation of gs was simulated and a model of scaling up gs to gc was developed. Results indicated that gs showed typical diurnal pattern with peaks occurred around 10:00-14:00. The gs increased with the increase of PAR, but decreased with the increase of VPD. And the diurnal variation of gs could be better expressed by the developed gs model using PAR and VPD. The scaling model was developed by integrating to achieve scaling up from gs to gc.