基于称重式蒸渗仪的淮北平原冬小麦蒸散估算模型的本地化

为了解不同作物蒸散量估算方法在淮北地区的适用性,利用新马桥实验站称重式蒸渗仪测定了2016-2017年冬小麦全生育期的实际蒸散值,结合Hargreaves-Samani(H-S)、 FAO-56 PM、Turc、Makkind(Mak)、 Priestley-Taylor(P-T)、Mcloud(Mcl)和DeBruin-Keijman(D-K)7个模型,分析了冬小麦田的蒸散特征,将蒸散的估算值(ET_0)和实测值(ET_C)进行了对比。结果表明,相对于ET_C值,7个模型拟合得到的ET_0的RMSE值为0.99～2.29 mm·d~(-1),且H-S FAO-56 PMTurcMakP-TMclD-K; ET_C与ET_0的相关系数为0.74～0.97,其中FAO-56 PM的相关性最高,P-T、 Mak、 D-K、 H-S也表现出较好的相关性。综合来看,H-S法总体表现较好,更适合该地区。对6种主要气象要素与实测蒸散值进行主成分分析发现,温度是影响ET_C的主要因子,湿度、日照时数和平均风速(2 m)对淮北冬小麦田蒸散值的影响不大;H-S模型以温度数据为基础,利用线性订正法和湿度指数项订正法将H-S模型本地化后检验发现,其优化结果良好,RMSE降低(0.68 mm·d~(-1))。

Calibration of Evapotranspiration for Winter Wheat Based on the Value of Weighing Lysimeter Measurements in Huaibei Plain

The accurate estimation of reference crop evapotranspiration(ET₀) is important for evaluating agricultural water use efficiency. In this paper, the evapotranspiration characteristics of winter wheat field were analyzed by using the measured evapotranspiration values determined by the weighing lysimeter measurements in Xinmaqiao experimental station during the whole growth period from 2016 to 2017. The estimated evapotranspiration values were compared with the measured values. Results showed that according to RMSE(range from 0.99 to 2.29 mm·d^-1), the models ranked as Hargreaves-Samani(H-S)> FAO-56 PM>Turc>Makkind(Mak) > Priestley-Taylor(P-T) >Mcloud(Mcl) >DeBruin-Keijman(D-K); according to correlation coefficient(0.74-0.97), the models ranked as:FAO-56 PM> P-T=Mak=D-K>H-S>Turc>Mcl; the deviation of H-S method is the smallest(RMSE is 0.99 mm·d^-1), and the correlation is good(r=0.95), which is more suitable for this climate region. Principal component analysis of different meteorological factors and measured evapotranspiration(ET_C) showed that temperature was the main factor affecting ET_C, while humidity had little effect on the evapotranspiration value of winter wheat field in Huaibei. Based on H-S model, the winter wheat evapotranspiration model with revised parameters was obtained. The optimization effect is good, and RMSE is reduced(0.68 mm·d^-1).