根据Hargreaves-Samani模型估算博州参考作物蒸散量

Estimation of Reference Crop Evapotranspiration in Bozhou Based on Hargreaves-Samani Model

摘要: 参考作物蒸散量既同时在水分循环和能量循环中扮演重要角色，又在区域干湿状况评价、作物需水量估算和水资源合理规划等实用领域中决策的发挥重要作用的关键因子，不仅为了解博州参考作物蒸散量的时空分布特征，同时也为了评价Hargreaves-Samani模型估算参考作物蒸散量的精度，本研究使用了博州2016年至2024年4个国家气象站的日最高最低温度、平均温度、相对湿度、日照时数、10 m高风速等数据，分析了博州地区温度和相对湿度的时间变化以及参考作物蒸散量的时空变化，对Hargreaves-Samani模型的估计精度进行了评价，评价标准为Penman-Monteith模型得到的参考作物蒸散量，得出以下结论：(1) 对由采取了适用全球范围的k_Rs系数的HS方法得到的2016~2024年博州的参考作物蒸散量数据进行分析，发现博州参考作物蒸散量均呈现上升趋势。(2) 根据2016~2024博州年均参考作物蒸散量空间分布图分析，阿拉山口与精河成为蒸散量高中心，分别为历年平均3.834 mm/day和3.896 mm/day，温泉成为低值中心，为2.913 mm/day，博乐则为3.199 mm/day。推测是由于其特殊的地理环境以及辐射情况所致。(3) 对HS方法的两种结果和PM的结果进行比较，对于选取了两个不同的k_Rs系数的HS方法的逐年参考作物蒸散量变化趋势和PM法的基本一致，但HS提出的全球普适方程得到的k_Rs与P. Paredes等人提出的根据气候类型划分的k_Rs存在差异。其结果证明在气候偏向干旱的博州，经过气候修正的HS法更加准确。

Abstract: Reference crop evapotranspiration not only plays an important role in water cycle and energy cycle, but also plays an important role in decision-making in practical fields such as regional dry and wet condition evaluation, crop water demand estimation and rational water resources planning. In order to understand the temporal and spatial distribution characteristics of reference crop evapotranspiration in Bozhou, but also to evaluate the accuracy of Hargreaves-Samani model in estimating reference crop evapotranspiration, this study used the daily maximum and minimum temperature, average temperature, relative humidity, sunshine hours, 10 m high wind speed and other data from four national weather stations in Bozhou from 2016 to 2024 to analyze the temporal and spatial changes of temperature and relative humidity and reference crop evapotranspiration in Bozhou. The estimation accuracy of Hargreaves-Samani model is evaluated, and the evaluation standard is Penman-Monteith. The results are as follows: (1) By analyzing the reference crop evapotranspiration data of Bozhou from 2016 to 2024 obtained by HS method with k_Rs coefficient applicable to the world, it is found that the reference crop evapotranspiration of Bozhou shows an upward trend. (2) According to the analysis of the spatial distribution map of annual reference crop evapotranspiration in Bozhou from 2016 to 2024, Alashankou and Jinghe have become high evapotranspiration centers, with an average of 3.834 mm/day and 3.896 mm/day over the years, respectively. Hot springs have become low value centers, with an average of 2.913 mm/day, and bole is 3.199 mm/day. It is speculated that it is due to its special geographical environment and radiation conditions. (3) Comparing the two results of HS method with that of PM method, the annual reference crop evapotranspiration variation trend of HS method with two different k_Rs coefficients is basically the same as that of PM method, but the k_Rs obtained from the global universal equation proposed by HS is different from the k_Rs divided according to the climate type proposed by P. Paredes et al. The results show that the HS method with climate modification is more accurate in Bozhou, where the climate is prone to drought.