THE SIGNIFICANCE OF THE DUAL SOLUTIONS FOR HEAT FLUXES MEASURED BY THE TEMPERATURE-FLUCTUATION METHOD IN STABLE CONDITIONS

De Bruin (1994) noted that, in stable conditions, there exist two solutions of the governing equations of the temperature fluctuation method. By examination of the governing equations, a quantitative description of the nature and behaviour of these solutions is given. The influence of extra sources of temperature variance is discussed, and is shown to lead to an occasional failure of the analysis procedure. The existence of both solutions in the real stably stratified boundary layer is discussed, and evidence is supplied from data collected in a nocturnal boundary layer in Niger, West Africa.