三江平原寒地稻田蒸散量估算研究

Estimation of the Evapotranspiration of Cold Rice on Sanjiang Plain

基于非称重式蒸渗仪测定的寒地稻田实际蒸散量,探讨波文比能量平衡法和Penman-Monteith参考作物蒸散-作物系数法(PM-Kc模型)在寒地稻田蒸散量计算中的适用性。结果表明,波文比能量平衡法估算的蒸散量较实测蒸散量偏低9.1%,但总体有较好的相关性(R2=0.87);校正后的PM-Kc模型低估了水稻生长中期和后期的累积ET,但其相对误差均小于10%,而生长初期,PM-Kc模型得到的累积ET比实测的累积ET_a高19.34%,以生长初期为例进一步分析PM-Kc模型与实际蒸散ET_a的关系,展现了随着间隔日数的增加,RMSE、MAE有降低的趋势,一致性系数d有提高的趋势,PM-Kc模型得到的7日平均模拟实际蒸散与实测蒸散数据最为接近。

Based on the actual evapotranspiration of cold rice measured by the non-weighing lysimeter, the applicability of the Bowen ratio energy balance method and the Penman-Monteith reference evapotranspiration-crop coefficient method（PM-Kc model） in the estimation of the evapotranspiration of cold rice was discussed. The results showed that the evapotranspiration estimated by the Bowen ratio energy balance method was 9.1% lower than the measured actual evapotranspiration, but overall there was a good correlation between them, with the R2 of 0.87. The corrected PM-Kc model underestimated the cumulative ET of cold rice in the medium-term growth and the late-term growth stage, but the relative error was less than 10%, while the cumulative ET of cold rice in the stage of early growth estimated by the PM-Kc model was 19.34% higher than the measured actual cumulative ET. It was shown that RMSE and MAE decreased while the consistency coefficient increased with the increase of the number of interval days, through the further analysis of the relationship between the estimated evapotranspiration and the measured actual evapotranspiration of cold rice in the stage of early growth. And the 7 days ＇ average evapotranspiration estimated by PM-Kc model was closest to the measured actual evapotranspiration.