Attributing the energy imbalance by concurrent lysimeter and eddy covariance evapotranspiration measurements

The commonly observed lack of energy balance closure at eddy covariance flux tower sites represents an outstanding problem in micrometeorology and significantly compromises the value of eddy covariance latent and sensible heat flux measurements. Here we used concurrent lysimeter and eddy covariance evapotranspiration measurements to correct for the energy imbalance attributable to the eddy covariance latent heat flux measurements (32%) and then, by assuming that the Bowen ratio is correctly quantified by the eddy covariance method, attributed the remainder of the energy balance to the sensible heat flux (10%) and the available energy (58%). We discuss our findings with respect to the ongoing discussion on the causes of the energy imbalance and approaches to force energy balance closure.