A Methodology for Providing Surface-Cover-Corrected Net Radiation at Heterogeneous Eddy-Covariance Sites

Abstract

A one-point measurement of net radiation is typically not representative of radiative energy available for the turbulent exchange of latent and sensible heat at eddy-covariance sites with heterogeneous surface cover. We propose a methodology for providing surface-cover-corrected net radiation matching the footprint of turbulent fluxes at a heterogenous eddy-covariance site. This is demonstrated at a complex sub-alpine site in southern central Norway over a week. The methodology is assessed by comparing the energy balance closure calculated with the regular one-point net radiation measurement at the flux tower against the surface-cover-corrected net radiation. The assessment indicates a decrease in the energy imbalance by 8% when assessed with the energy balance ratio, but no improvement is revealed when assessed with regression methods. However, only a small dataset serves as basis for this demonstration, and the findings therefore cannot necessarily be generalized. Further testing and application of the methodology is required to understand the full effect of surface-cover-correcting mismatching footprints of turbulent fluxes and net radiation at heterogeneous eddy-covariance sites.