With the software package TK3 for the calculation of eddy-covariance data a programme version was developed, which is based on more than 25 years experiences. The fact that micrometeorological measurements of energy exchange processes at the surface are often not able to close the energy balance (Foken and Oncley 1995) motivated us to address the issue of quality assurance of these surface energy flux measurements. The methodology of determining turbulent heat fluxes with their corrections and quality tests is one key issue in this context. Therefore, in order to obtain quality assured turbulent fluxes, at the University of Bayreuth the comprehensive software package TK2 (Mauder and Foken 2004) was developed, which was updated with the version TK3 (Mauder and Foken 2011). The present version includes some more features but was not changed in all basic calculations.

{"references": ["Foken, T., Leuning, R., Oncley, S. P., Mauder, M., and Aubinet, M. Corrections and data quality. Aubinet, M., Vesala, T., and Papale, D. Eddy Covariance: A Practical Guide to Measurement and Data Analysis. (4), 85-132. 2012. Dordrecht, Springer.", "Mauder, M., Cuntz, M., Dr\u00fce, C., Graf, A., Rebmann, C., Schmid, H. P., Schmidt, M., and Steinbrecher, R. A strategy for quality and uncertainty assessment of long-term eddy-covariance measurements. Agricultural and Forest Meteorology 169, 122-135. 2013.", "Fratini, G. and Mauder, M. Towards a consistent eddy-covariance processing: an intercomparison of EddyPro and TK3. Atmos.Meas.Tech. 7(7), 2273-2281. 2014."]}