Some aspects of the energy balance closure problem T. Foken, F. Wimmer, M. Mauder, C. Thomas, and C. Liebethal Department of Micrometeorology, University of Bayreuth, 95440 Bayreuth, Germany
Abstract. After briefly discussing several reasons for the energy balance closure
problem in the surface layer, the paper focuses on the influence of the low
frequency part of the turbulence spectrum on the residual. Changes in the
turbulent fluxes in this part of the turbulence spectrum were found to have
a significant influence on the changes of the residual. Using the ogive
method, it was found that the eddy-covariance method underestimates
turbulent fluxes in the case of ogives converging for measuring times longer
than the typical averaging interval of 30 min. Additionally, the
eddy-covariance method underestimates turbulent fluxes for maximal ogive
functions within the averaging interval, both mainly due to advection and
non-steady state conditions. This has a considerable influence on the use of
the eddy-covariance method.
Citation: Foken, T., Wimmer, F., Mauder, M., Thomas, C., and Liebethal, C.: Some aspects of the energy balance closure problem, Atmos. Chem. Phys., 6, 4395-4402, doi:10.5194/acp-6-4395-2006, 2006.