New equations for sonic temperature variance and buoyancy heat flux with an omnidirectional sonic anemometer

Many new types of sonic anemometer obtain sonic temperature from an average value of temperature measured along three paths, unlike previous sonic ane mometers that generally used one path. New equations are derived to calcula te temperature variance from sonic temperature variance and sensible heat f lux from buoyancy flux considering the influence of a crosswind. These equa tions can be applied to CSAT3, Solent R2, R3, R3A, HS, and USA-1 sonic anem ometers with the corresponding correction factors given in this paper. The equations are verified by data measured by a CSAT3 sonic anemometer in the LITFASS-1998 field study.