Transpiration peak over a hill evergreen forest in northern Thailand in the late dry season: Assessing the seasonal changes in evapotranspiration using a multilayer model
Transpiration peak over a hill evergreen forest in northern Thailand in the late dry season: Assessing the seasonal changes in evapotranspiration using a multilayer model
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DOI：
10.1029/2002jd003028
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发表时间：
2003-09
影响因子：
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通讯作者：
Katsunori Tanaka;Hideki Takizawa;N. Tanaka;I. Kosaka;N. Yoshifuji;C. Tantasirin;Sirithanya Piman;Masakazu Suzuki;N. Tangtham
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文献类型：
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作者：
Katsunori Tanaka;Hideki Takizawa;N. Tanaka;I. Kosaka;N. Yoshifuji;C. Tantasirin;Sirithanya Piman;Masakazu Suzuki;N. Tangtham
[1]采用多层模式和冠层以上边界条件对亚洲季风区泰国北部（18°48′n, 98°54′e）山地常绿森林蒸散发的季节变化进行了模拟。模拟考虑了光合作用和气孔导度模型的叶面积指数（LAI）和生理参数的不确定性。参数以LAI估算值为基础，参考单叶的净光合速率和气孔导度测定值确定。模拟的累积蒸散量和降水截留量与在这些不确定性条件下从水收支中得到的值一致。还研究了这些极限对蒸发和蒸腾的敏感性。模拟蒸腾量在旱季后期达到峰值。利用涡动相关技术获得的潜热通量表明，森林在旱季后期继续蒸腾。热脉冲速度还显示，单株树木的用水量在旱季后期达到峰值。这些结果反驳了先前报道的泰国常绿森林和其他植被在旱季蒸散量下降的观点。蒸腾峰值被认为取决于冠层湿度的减少，以及由此导致的蒸发的缺乏，以及即使在最干燥的条件下气孔导度也几乎没有下降的事实。
[1] The seasonal changes in evapotranspiration over a hill evergreen forest in northern Thailand (18°48′N, 98°54′E), in the Asian monsoon region, were simulated using a multilayer model and the boundary conditions above the canopy. The simulation considered the uncertainty in the leaf area index (LAI) and physiological parameters for both photosynthesis and stomatal conductance models. The parameters were based on the estimated LAI and determined by referring to the measured net photosynthesis rate and stomatal conductance for a single leaf. The simulated cumulative evapotranspiration and rainfall interception agreed with the values obtained from the water budget within these uncertainties. The sensitivity of these limits to both evaporation and transpiration was also investigated. The simulated transpiration peaked in the late dry season. The latent heat flux obtained with the eddy correlation technique showed that the forest continued to transpire in the late dry season. The heat pulse velocities also showed a peak in water use by individual trees in the late dry season. These results counter the view that evapotranspiration declines in the dry season, as has been reported previously for an evergreen forest and other vegetation in Thailand. The transpiration peak was thought to depend on the reduced wetness of the canopy, and the consequent lack of evaporation from it, and on the fact that there was little decline in stomatal conductance, even in the driest conditions.