Energy fluxes and the Priestley–Taylor parameter over winter wheat and maize in the North China Plain
Energy fluxes and the Priestley–Taylor parameter over winter wheat and maize in the North China Plain
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DOI：
10.1002/hyp.5528
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发表时间：
2004-08
影响因子：
3.2
通讯作者：
Yongqiang Zhang;Changming Liu;Qiang Yu;Yanjun Shen;Eloise Kendy;A. Kondoh;C. Tang;Hongyong Sun
中科院分区：
文献类型：
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作者：
Yongqiang Zhang;Changming Liu;Qiang Yu;Yanjun Shen;Eloise Kendy;A. Kondoh;C. Tang;Hongyong Sun
1999-2000年，利用波文比能量平衡技术对华北平原井灌冬小麦和玉米冠层上方的地表能量通量进行了观测。潜热通量λE与有效能Rn − G之比的季节变化表明，当叶面积指数（LAI）在2.0 ~ 6.0之间变化时，λE与Rn − G之比超过83%。冬小麦蒸发量（EF）的季节变化趋势与叶面积指数（LAI）的变化趋势相似，叶面积指数是控制EF的关键因子，它本身反映了有效能量在λE中的分配。小麦和玉米冠层的Priestley-Taylor参数α在一个生长季内变化较大，连续两年冬小麦的季节平均α分别为1.17和1.26，玉米的季节平均α分别为1.06和1.09。冬小麦α与0-20 cm土壤水分呈指数相关，玉米α与0-20 cm土壤水分无显著相关性，且随土壤深度的增加，α与土壤水分的相关性减弱。在不同土壤水分条件下，冬小麦叶片水势与土壤可提取水呈线性相关。
Surface energy fluxes above the canopies of well‐irrigated winter wheat and maize in the North China Plain were measured by the Bowen‐ratio energy balance technique in 1999–2000. Seasonal variation of the ratio of latent heat flux λE to available energy Rn − G showed that the ratio of λE to Rn − G exceeded 83% when leaf area index (LAI) varied from 2·0 to 6·0. The seasonal trend of evaporative fraction (EF) for winter wheat was similar to that of LAI before senescence stage, which is a critical factor controlling EF, which itself reflects the partitioning of available energy into λE. The Priestley–Taylor parameter α over the wheat and maize canopies changed greatly over the course of a growing season, and the seasonal average α of winter wheat was 1·17 and 1·26, and that of maize was 1·06 and 1·09 in the two consecutive years. α for winter wheat was exponentially correlated to 0–20 cm surface soil moisture, but not for maize and with the increase of soil depths, the correlation between α and soil moisture was weak. Under different soil moisture conditions, a linear correlation between extractable soil water and leaf water potential ψ for winter wheat was found. Copyright © 2004 John Wiley & Sons, Ltd.