A comparison of methods for determining field evapotranspiration: photosynthesis system, sap flow, and eddy covariance
A comparison of methods for determining field evapotranspiration: photosynthesis system, sap flow, and eddy covariance
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测定田间蒸散量的方法比较：光合作用系统、液流和涡流协方差
DOI：
10.5194/hess-18-1053-2014
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发表时间：
2013-11
影响因子：
6.3
通讯作者：
Yang, P.
中科院分区：
文献类型：
--
作者：
Zhang, Z.;Tian, F.;Hu, H.;Yang, P.
采用多尺度、多技术研究了膜下滴灌条件下棉田蒸散量及其各组分的变化规律。在不同尺度上使用了三种测量技术：光合系统（叶尺度），液流（植物尺度）和涡度相关（场尺度）。实验于2012年7月至9月进行。为了将蒸散量从叶片尺度扩大到植物尺度，提出了一种结合冠层结构和日照和遮荫叶片之间关系的方法。为了将蒸散量从植物尺度扩大到田间尺度，采用了基于单位叶面积蒸腾量的方法，并在叶面积与茎直径之间的关系中加入了时间变异性。在植物尺度上，基于光合作用系统的蒸腾速率估算值略高于液流估算值（18%）。在田间尺度上，基于液流和涡度相关的蒸腾估算结果与棉花吐絮期的结果吻合较好，可以忽略土壤蒸发的影响。结果表明，所提出的尺度放大方法是合理有效的.基于实测资料和尺度放大方法，分析了膜下滴灌棉田蒸散量的组成。在7月和8月的两个分析子期间，蒸散率分别为3.94和4.53米天1。滴灌前蒸腾量占蒸散量的比例为87.1%，灌水后为82.3%.蒸腾量占蒸散量的比例高的主要原因是滴灌管上方有覆膜，膜间土壤含水量低，冠层封闭性好，作物需水量高。
A multi-scale, multi-technique study was con- ducted to measure evapotranspiration and its components in a cotton field under mulched drip irrigation conditions in northwestern China. Three measurement techniques at dif- ferent scales were used: a photosynthesis system (leaf scale), sap flow (plant scale), and eddy covariance (field scale). The experiment was conducted from July to September 2012. To upscale the evapotranspiration from the leaf to plant scale, an approach that incorporated the canopy structure and the rela- tionships between sunlit and shaded leaves was proposed. To upscale the evapotranspiration from the plant to field scale, an approach based on the transpiration per unit leaf area was adopted and modified to incorporate the temporal variabil- ity in the relationship between leaf areas and stem diame- ter. At the plant scale, the estimate of the transpiration based on the photosynthesis system with upscaling was slightly higher (18 %) than that obtained by sap flow. At the field scale, the estimates of transpiration derived from sap flow with upscaling and eddy covariance showed reasonable con- sistency during the cotton's open-boll growth stage, during which soil evaporation can be neglected. The results indi- cate that the proposed upscaling approaches are reasonable and valid. Based on the measurements and upscaling ap- proaches, evapotranspiration components were analyzed for a cotton field under mulched drip irrigation. During the two analyzed sub-periods in July and August, evapotranspiration rates were 3.94 and 4.53 m day 1 , respectively. The fraction of transpiration to evapotranspiration reached 87.1 % before drip irrigation and 82.3 % after irrigation. The high fraction of transpiration over evapotranspiration was principally due to the mulched film above the drip pipe, low soil water con- tent in the inter-film zone, well-closed canopy, and high wa- ter requirement of the crop.
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影响因子：
6.2
作者：
W. Dugas;M. L. Heuer;D. Hunsaker;B. Kimball;K. Lewin;J. Nagy;M. Johnson
通讯作者：
W. Dugas;M. L. Heuer;D. Hunsaker;B. Kimball;K. Lewin;J. Nagy;M. Johnson
影响因子：
11.6
作者：
D. Mackay;D. Ahl;B. Ewers;S. Gower;S. N. Burrows;S. Samanta;K. Davis
通讯作者：
D. Mackay;D. Ahl;B. Ewers;S. Gower;S. N. Burrows;S. Samanta;K. Davis
影响因子：
5
作者：
Lixin Wang;S. Niu;S. Good;K. Soderberg;M. Mccabe;R. Sherry;Yiqi Luo;Xuhui Zhou;J. Xia
通讯作者：
Lixin Wang;S. Niu;S. Good;K. Soderberg;M. Mccabe;R. Sherry;Yiqi Luo;Xuhui Zhou;J. Xia
影响因子：
5.4
作者：
Loranty, Michael M.;Mackay, D. Scott;Kruger, Eric L.
通讯作者：
Kruger, Eric L.
DOI：
--
发表时间：
1978-09
期刊：
--
影响因子：
--
作者：
B. A. Barry;M. Morris
通讯作者：
B. A. Barry;M. Morris