| 玉米农田水热通量动态与能量闭合分析 |
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| 引用本文： | 李君,许振柱,王云龙,周莉,周广胜.玉米农田水热通量动态与能量闭合分析[J].植物生态学报,2007,31(6):1132-1144. |
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| 作者姓名： | 李君 许振柱 王云龙 周莉 周广胜 |
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| 作者单位： | (1 中国科学院植物研究所植被与环境变化国家重点实验室，北京 100093);(2 中国科学院研究生院，北京100049) |
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| 基金项目： | 中国气象局科技研究项目;国家重点基础研究发展计划(973计划) |
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| 摘 要： | 基于锦州农田生态系统野外观测站玉米农田涡度相关系统近2年的水热通量观测数据，分析了玉米农田水热通量的日际、年际变化特征及其能量 平衡状况。结果表明： 1）玉米农田水热通量日变化与年变化均呈单峰型二次曲线，峰值出现在12∶00～13∶00左右，与净辐 射的日变化、年 变化同步，潜热通量最大可达到655 w•m－2（出现在2004年7月8日1 3∶00），显热通量最大值大约为369 w•m－2（出现在2004年5月31日13∶ 00）。2）玉米农田水热通量强度与局地的环境条件密切相关：显热通量与大气压的年变化呈负相关，潜热通量与气温年变化呈正相关。水热通 量受降水的影响较大，对降水的反应较敏感。其中，潜热通量(LE)不仅与降水的强度有关，而且随着降水的季节分布的不同而出现不同的响应 ，即使同样量级的降水在夜间与白天对LE的影响也是不同的。3）玉米农田通量观测呈现能量不闭合现象，主要原因可能是未包含0～5 cm土壤 热储量与冠层热储量，造成大约15.5%的能量损失。
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| 关 键 词： | 玉米农田 潜热通量 显热通量 日变化 年变化 |
| 收稿时间： | 2006-11-01 |
| 修稿时间： | 2007-02-05 |
LATENT AND SENSIBLE HEAT FLUXES AND ENERGY BALANCE IN A MAIZE AGROECOSYSTEM |
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| LI Yi-Jun,XU Zhen-Zhu,WANG Yun-Long,ZHOU Li,ZHOU Guang-Sheng.LATENT AND SENSIBLE HEAT FLUXES AND ENERGY BALANCE IN A MAIZE AGROECOSYSTEM[J].Acta Phytoecologica Sinica,2007,31(6):1132-1144. |
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| Authors: | LI Yi-Jun XU Zhen-Zhu WANG Yun-Long ZHOU Li ZHOU Guang-Sheng |
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| Affiliation: | 1Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Aims Agroecosystems are influenced strongly by human activity and climate change. In order to scientifically manage agroecosystems under climate change, it is important to understand water exchange and energy transfer between agroecosystems and the atmosphere. We analyze latent and sensible heat fluxes of a maize agroecosystem as a case study. Methods Latent and sensible heat fluxes were measured in a maize agroecosystem using a 3.5 m eddy covariance tower from June 2004 to December 2005 at the Jinzhou maize agricultural ecosystem field observation station (Liaoning Province, China). Meteorological factors were recorded using sensors at 2.3 and 4.1 m using a micrometeorological tower. Important findings Diurnal and annual variations of latent heat fluxes and sensible heat fluxes had the same characteristics as net radiation and could be expressed as hyperbola curves. Their peak values appeared at 12∶00-13∶00. The maximum latent heat flux was about 655 w•m-2 (at 13∶00 July 8, 2004), and the maximum sensible heat flux was 369 w•m-2 (at 13∶00 May 31, 2004). The intensities of latent heat fluxes and sensible heat fluxes had close relationships with environmental factors. Latent heat flux was negatively correlated with atmospheric pressure, and sensible heat flux was positively correlated with air temperature. Fluxes of latent and sensible heat were very sensitive to precipitation. Latent heat flux was greatly affected by the intensity and timing of precipitation, regardless of seasonal and daily changes. Energy of the maize agroecosystem was unbalanced with the loss of about 15.5%, possibly because of lack of knowledge of 0-5 cm soil heat reserve and canopy heat reserve. The energy balance had obvious differences between cloudy and rainy days, with the loss of energy much less on rainy than cloudy days, especially with a surplus of energy on rainy days in August. |
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| Keywords: | maize farmland latent flux sensible heat flux diurnal variation annual variation |
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