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

Abstract

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 a@/&, and the third gives the value of the flux when Q, = 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. Purpose of Study

The Analytical Objective Hysteresis Model (AnOHM v1.0): methodology to determine bulk storage heat flux coefficients

“…Parameterization as a function of Q * : either as a linear function (Oke et al, 1981), hyperbolic (cotangent, secant) function (Doll et al, 1985), or hysteresis relation (Camuffo and Bernardi, 1982). The last of these is used in the Objective Hysteresis Model (OHM) (Grimmond et al, 1991).…”

Estimating Soil Heat Flux for Alfalfa and Clipped Tall Fescue Grass

“…For example, for DOY 184 different G values for a given R n occurred during the midnight to noon hours compared to the noon to midnight hours, since the diurnal G and R n waves did not reach their peak values at the same time. Hysteresis in the diurnal relationship between G and R n has previously been reported by Camuffo and Bernardi (1982), Novak (1993), and Domingo et al (2000).…”

“…It, therefore, cannot be used to calculate G at other times of the day. Camuffo and Bernardi (1982) proposed the following model to calculate G as a function of time:…”

Standardized Asce Penman-Monteith: Impact of Sum-of-Hourly vs. 24-Hour Timestep Computations at Reference Weather Station Sites

“…Although the fixed fractions of R n are widely used in the estimations of G, Camuffo and Bernardi (1982) showed this ratio to vary considerably during the day. One of the issues with using a fixed fraction of R n to estimate G is that the relationship between G and R n suffers from hysteresis effects (Payero et al, 2001).…”