By finding the covariance between the vertical wind speed fluctuations with temperature as determined by the CSAT3 or CA27 (with 127TC) against humidity and carbon dioxide fluctuations, as measured by fast response sensors like a fine wire thermocouple (FW05), krypton hygrometer (KH20), or an open path CO₂/H₂O analyser (CS7500), the sensible and latent heat flux, as well as vapor and CO₂ fluxes, can be found. Virtual sensible heat flux can be determined by finding the covariance between the sonically determined temperature and vertical wind speed fluctuations.