基于SHAW模型的冬小麦叶温模拟

Simulation of Winter Wheat Leaf Temperature Based on SHAW Model

摘要:

叶温是反映冬小麦健康状况的关键指标，但获取麦田叶温动态变化过程及廓线分布存在着较大困难。本文以河南省商丘市为研究区，引入表达土壤-植被-大气能量传输的SHAW模型，对其进行本地化标定，在垂直方向上0~60cm高度以10cm为间隔进行分层，模拟冬小麦拔节期至抽穗期间的叶温时序曲线及廓线，并结合田间同期不同高度的叶温实测数据，对模拟结果进行分析。结果表明：SHAW模型可有效地用于麦田叶温时序曲线和廓线模拟，决定系数达0.8476，夜间模拟效果显著优于白天，决定系数分别为0.8622和0.7602。对叶温日平均值、最低值和最高值的分析表明，均方根误差范围为1.36~4.09℃，且最低温模拟效果最好，平均值次之，最高温误差最大。叶温廓线模拟分析表明，各高度决定系数均达到0.82以上，且随高度的增加而增大，均方根误差范围为2.41~3.35℃，平均误差均小于0℃；叶温总体上呈现出夜间随高度增加而降低的趋势，而白天随高度增加而升高的趋势。

关键词:冬小麦;叶温模拟;叶温廓线;SHAW模型

Abstract:

Leaf temperature is the key factor that reflects the growth conditions of winter wheat, but it is difficult to obtain the dynamic variation and profile distribution of wheat field leaf temperature. The simultaneous heat and water (SHAW) model describes heat and water movement in a plant-snow-residue-soil system in detail.Taking Shangqiu as the study area, based on the localization,the SHAW model was used to simulate the leaf temperature time series curve and profile from 0cm to 60cm separated by 10cm from jointing period to heading period of winter wheat.The simulation results were analyzed by combining with field observed data at the same time. The results showed that the SHAW model can be used effectively to simulate leaf temperature time series curve and profile, and the coefficient of determination reached to 0.8476. The night simulation results were significantly better than the daytime,and the coefficient of determination were 0.8622 and 0.7602 respectively. The analysis of the average, minimum and maximum values of leaf temperature simulation showed that RMSE ranged from 1.36℃ to 4.09℃. The minimum temperature simulation effect was the best, and the average value was second, and the maximum temperature error was the greatest. The analysis of the leaf temperature profile showed that height decision coefficient all achieved above 0.82, and increased with the height. RMSE was ranged from 2.41℃ to 3.35℃, and MBE were all less than 0℃. The leaf temperature generally showed a tendency to decrease with the height in the night, while increase with the height during the day.

Key words:winter wheat;leaf temperature simulation;leaf temperature profile;SHAW model