The eddy covariance technique has become the standard method for measuring the sensible and latent heat fluxes, as well as the fluxes of carbon dioxide and other trace gases, needed for atmospheric, meteorological, climatological, hydrological, ecological and agricultural research and practical applications. For example, these data are critical to the calibration and evaluation of the numerical and remote sensing models used for such applications as predicting weather and climate, evaluating water use in agriculture, and understanding the impacts of climate change on ecosystem health. However, the lack of energy balance closure in eddy covariance measurements, which is required by the models, results in a level of uncertainty that can hamper model development and validation activities and adversely impact operational applications. The session will provide an opportunity to update the state of the scientific knowledge concerning the sources of errors and any associated uncertainties in energy balance components caused by instrumentation, measurement techniques, landscape heterogeneity and the neglect of importance of factors such as heat storage and advection. The session will also focus on the impacts of this uncertainty on the land surface modeling community. It is also intended to provide an opportunity to seek new and novel insights into this long-standing issue and improve our understanding of how interactions between the atmosphere and the land surface affect the measurement and modeling of surface fluxes.

