An observational study of heat fluxes and their relationships with net radiation

Experimental evidence indicates that the diurnal behaviour of the fluxes of heat into the ground and into the atmosphere versus the net flux of radiation can be modelled by closed curves, the hourly values folowing one another in either a clockwise or counter clockfashion. A general formulation to express the different heat fluxes as a function of net radiation ? is proposed. This relationship between the different heat fluxes and ? can be expressed as a sum of three terms: the first indicates a direct proportionality to ?, the second gives the deviation from linearity and depends on ??/?t, and the third gives the value of the flux when ? = 0. The formulae are then expressed as a function of time and the ratios between the heat fluxes and ? are evaluated. A comparison with the approximations generally used shows that the latter may be considered as particular cases of the more general equations proposed here.