A validation of eddy covariance technique for measuring crop evapotranspiration on different time scales in the North China Plain

Accurate determination of evapotranspiration (ET) has tremendous potential in guiding irrigation and improving the efficiency water resources utilization North China Plain. Eddy covariance (EC) method is currently a popular for determining field-scale ET. However, due to varying foot print unclosed energy balance, applicability EC different regions needs be tested corrected. In present work, we compared ET winter wheat – summer maize rotation cropland measured by with large-scale lysimeters on time scales. The degree balance closure measurements this region 78%. After adjusted using Bowen ratio forced method, monitored comparable those lysimeters. results also indicated that consistency observed got better an increasing scale, especially multi-year average values relative deviation less than 1%. short-time events such as precipitation mismatch footprint area small fixed source lysimeter should responsible discrepancy two methods daily scale. factors crop biomass, total available water, local climate condition exert more effects large Overall, technique measurement