Modeling water temperature in a rice paddy for agro-environmental research
Modeling water temperature in a rice paddy for agro-environmental research
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DOI：
10.1016/j.agrformet.2008.06.011
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发表时间：
2008-10
影响因子：
6.2
通讯作者：
T. Kuwagata;T. Hamasaki;Tsutomu Watanabe
中科院分区：
文献类型：
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作者：
T. Kuwagata;T. Hamasaki;Tsutomu Watanabe
稻田水温是影响水稻生长和产量的重要因子之一，也影响着稻田CH 4排放。我们建立了一个简单的稻田日平均水温模型。该模型分为两个步骤来评估稻田水温。在第一步中，根据气象数据（气温、比湿、风速、太阳辐射和向下长波辐射），通过日24小时平均或日间（夜间）12小时平均热平衡方程，计算无植被水面的日平均水温（Tw 0）。水表面的整体传热系数是计算Tw 0的关键参数。接着，通过对T <$w 0加上修正项，求出稻田内的日平均水温（T <$w）。这里，校正项被描述为叶面积指数（LAI），太阳辐射和风速的函数，公式是根据经验确定的。模型对稻田日平均水温的模拟效果较好，均方根误差为0.81-0.85°C。研究还表明，植物冠层对水温的影响不仅取决于冠层密度（LAI），还取决于太阳辐射和风速。T <$w通常低于T <$w 0，但在LAI=0.5-1.5的稻田中，在晴天大风条件下T <$w高于T <$w 0。这些特征被纳入本研究中开发的模型。
Water temperature in rice paddies (Oryza sativa L.) is one of the most important factors affecting the growth and yield of rice, and also influences CH4emission from paddy fields. We developed a simple model of the daily mean water temperature in a rice paddy. The model has two steps for evaluating the paddy water temperature. In the first step, the daily mean water temperature of a non-vegetated water surface (T¯w0) is evaluated from meteorological data (air temperature, specific humidity, wind speed, solar radiation, and downward longwave radiation) by daily 24-h mean or daytime (nighttime) 12-h mean heat balance equations. The bulk heat transfer coefficient at the water surface is a key parameter for evaluating T¯w0. Next, the daily mean water temperature in a rice paddy (T¯w) is evaluated by adding a correction term to T¯w0. Here, the correction term is described as a function of the leaf area index (LAI), solar radiation, and wind speed, and the formula was determined empirically. The model simulated fairly well the daily mean water temperature of rice paddies with root mean square errors of 0.81–0.85°C. This study also demonstrated the important result that the influence of a plant canopy on water temperature depends not only on canopy density (LAI), but also on solar radiation and wind speed. T¯wwas usually lower than T¯w0, but in rice paddies with LAI=0.5–1.5, T¯wwas higher than T¯w0under strong wind conditions in sunny weather. These characteristics were incorporated into the model developed in this study.