Coupling land surface and crop growth models to estimate the effects of changes in the growing season on energy balance and water use of rice paddies
Coupling land surface and crop growth models to estimate the effects of changes in the growing season on energy balance and water use of rice paddies
复制标题
DOI：
10.1016/j.agrformet.2010.02.011
复制
发表时间：
2010-07
影响因子：
6.2
通讯作者：
A. Maruyama;T. Kuwagata
中科院分区：
文献类型：
--
作者：
A. Maruyama;T. Kuwagata
将作物生长模型与一个简单的地表模型耦合起来，以估计水稻(Oryza sativa L.)生长季变化的影响。关于稻田能量平衡和水分利用的研究。作物生长模型包括物候发育(Ps)、叶面积指数(LAI)和冠层高度(H)的计算。陆面模型包括利用作物生长模型(Ps、LAI、h)的输出计算能量平衡、辐射传输和气孔运动。在耦合模式下，仅根据气候资料即可计算稻田的能量通量和水/冠温度。在湿润温带气候条件下，对三个不同生长季节的试验点进行了全季观测，对模型进行了评估。计算的能量通量的季节变化与观测值吻合较好，均方根误差为10-20Wm2。为了了解生长季节的变化如何影响稻田的能量平衡和水分利用，基于日本宫崎县平原的气候数据，利用该模型估算了5个不同插秧期的水温/冠层温度和蒸散量的变化。在正常气候条件下，各生长季节(即移栽后水温高于气温，冠层温度低于气温，且随水稻生长而减小)的能量平衡有一个共同的趋势。根据1981~2000年20 a气候资料计算的水稻生育期总蒸散量/蒸散量比值(T/ET)，3月1日、4月1日、5月1日、6月1日和7月1日的平均值分别为0.40、0.48、0.48、0.46和0.36。这表明，以总蒸散量为基础的水分利用效率在季节中期移栽时较高。利用所提出的模型，可以在给定的气候条件和生长季节下估计稻田的用水量，从而为适应气候变化的生长季节和水分管理提供了可能。
A crop growth model was coupled to a simple land surface model to estimate the effect of changes in the growing season for rice (Oryza sativa L.) on the energy balance and water use of rice paddy fields. The crop growth model consisted of calculations of phenological development (Ps), growth of leaf area index (LAI) and canopy height (h). The land surface model consisted of calculations of energy balance, radiation transport and stomatal movements using the output of the crop growth model (Ps, LAI, h). Using a coupled model, the energy fluxes and water/canopy temperatures of rice paddies can be calculated from climatic data only. The model was evaluated using whole season observations at three experimental sites with different growing seasons in a humid temperate climate. The seasonal variations in calculated energy fluxes showed good agreement with observed values with a root mean square error of 10–20Wm2. To understand how the change in growing season affects energy balance and water use of rice paddies, variations in water/canopy temperatures and evapotranspiration were estimated using the model for five different transplanting times based on climatic data for the Miyazaki Plain in Japan. A common trend in energy balance was obtained for all growing seasons (i.e., water temperature was higher than air temperature, whereas canopy temperature was lower than air temperature after transplanting, and these differences decreases with rice growth) under normal climatic conditions. Mean values of the ratios of total transpiration to total evapotranspiration (T/ET) during the rice growth period based on climatic data from 20 years (1981–2000) were 0.40, 0.48, 0.48, 0.46 and 0.36 for transplanting at March 1, April 1, May 1, June 1 and July 1, respectively. This suggests that the water use efficiency based on total evapotranspiration would be higher for transplanting during mid-season. Using the proposed model, the water use by rice paddies can be estimated for given climatic conditions and growing seasons, which makes it possible to modify the growing season and water management for climate change.