A New Approach to Estimating the Sensible Heat Flux in Bare Soils

The estimation of sensible heat flux (H) in drylands is important because it constitutes a significant portion of the net available surface energy. A model to estimate H half-hourly measurements for bare soils was derived by combining the surface renewal (SR) theory and the Monin–Obukhov similarity theory (MOST), involving the land surface temperature (LST), wind speed, and the air temperature in a period of half an hour, H_SR-LST. The surface roughness lengths for momentum ((Formula presented.)) and for heat (z_0h) were estimated at neutral conditions. The dataset included dry climates and different measurement heights (1.5 m up to 20 m). Root mean square error ((Formula presented.)) over the mean actual sensible heat flux estimate (H_EC), E (Formula presented.), was considered excellent, good, and moderate for E values of up to 25%, 35%, and 40%, respectively. In stable conditions, H_SR-LST and H_MOST values were comparable and both were unacceptable (E > 40%). However, the RMSE using H_SR-LST ranged between 8 Wm² and 12 Wm² and performed slightly better than H_MOST. In unstable conditions, H_SR-LST was in excellent, good, and moderate agreement in 3, 6, and 5 cases, respectively; H_MOST was good in 3 cases; and the remaining 11 cases were intolerable because they required site-specific calibration.