中国东部典型森林生态系统蒸散及其组分变异规律研究

森林蒸散包括植被蒸腾、土壤蒸发、冠层截留蒸发三个组分,在陆地生态系统水分循环及能量流动研究中占有重要地位。论文基于Priestley-Taylor Jet Propulsion Laboratory Model （PT-JPL）模型,估算温带针阔混交林、人工常绿针叶林、亚热带常绿阔叶林三个典型森林生态系统2003-2008年蒸散（组分）;在模拟结果基础上揭示了蒸散（组分）的季节变异规律及主控因子。结果表明：①PT-JPL模型在中国东部森林生态系统蒸散及其组分估算中具有较高的稳定性和可靠性;②蒸散（组分）季节变化特征明显,不同森林生态系统类型变化规律差异较小,但主控因子存在较大差异：温带针阔混交林蒸散和植被蒸腾季节变异主要由净辐射和增强植被指数（EVI）共同控制,而亚热带人工常绿针叶林和亚热带常绿阔叶林主要受净辐射影响;EVI和饱和水汽压差（VPD）是土壤蒸发季节变异的主控因子,截留蒸发的季节变化则主要受VPD影响。

Study on the Variations of Forest Evapotranspiration and Its Components in Eastern China

The study of forest evapotranspiration (ET) occupies a significant position in the research of water and energy cycles, owing to the important role of forest ecosystem in the entire terrestrial ecosystem. In this paper, based on Priestley-Taylor Jet Propulsion Laboratory Model (PT-JPL), we simulated ET and its components for the temperate mixed broadleaf-coniferous forest, the artificial evergreen coniferous forest and the subtropical evergreen broad-leaved forest in eastern China from 2003 to 2008, and then validated the accuracy of PT-JPL model with flux data. In addition, seasonal variation characteristics and controlling factors of ET and its components were also studied. The results indicate that PT-JPL model is robust and accurate for estimating forest ET and its components. There are obvious seasonal variation of ET and its components in all three forest ecosystems, with similar variation trends. However, the main controlling factors dominating the seasonal variation of forest ET and its components vary in different forest ecosystems. The seasonal variation of ET and its components for temperate mixed broadleaf-coniferous forest are mainly controlled by net radiation and VPD, while those for artificial evergreen coniferous forest and subtropical evergreen broad-leaved forest are net radiation only. As for seasonal variation of soil evaporation, EVI and VPD are the major contributors in all three forest ecosystems, but when referring to the seasonal change of interception evaporation, VPD is considered as the dominant factor.