稻田逐时蒸散量的测定及其模拟方法的比较

Measurement Simulation of Hourly Evapotranspiration in Paddy Field with Different Methods

水稻生长季内,采用蒸渗计、涡度相关仪(EC)测定稻田逐时蒸散量,应用Penman-Monteith模型(PM模型)、Shuttleworth-Wallace双源模型(SW模型)进行模拟,并对比模拟值与观测值,验证了蒸散模型可靠性。结果表明:1涡度相关仪测定的稻田蒸散显著低于蒸渗计,蒸渗计测定的稻田蒸散较涡度相关法更为可靠。2SW模型模拟效果优于PM模型,模拟值与蒸渗计实测值更加接近,尤其在生育前期和后期水稻冠层稀疏时段。3稻田土壤蒸发占总蒸散比例较小且水层作用使阻力基数值降低,土壤阻力敏感性较旱地低。

Hourly evapotranspiration in paddy field was observed directly by lysimeter and eddy covariance method （EC）, and was simulated with using Penman-Monteith（PM） equation and Shuttleworth-Wallace （SW） model, respectively. The reliabilities of the two models were verified through comparing the observed and simulated evapotranspiration. The results showed that ① the measured evapotranspiration by EC were obvious lower compared with the lysimeter in each rice growth stage, and the reliability of measured evapotranspiration by lysimerter was higher. ②The simulated effect of Shuttleworth-Wallace model was better than Penman-Monteith equation, and the simulated evapotranspiration was closer to the measured evapotranspiration by lysimeter, especially during the periods with sparse canopy. ③Soil evaporation had a lower proportion in total evapotranspiration as well as a smaller resistance because of the water in the paddy, and the sensitivity of soil resistance was smaller than that in arid regions.