Parameterization of subsurface heating for soil and concrete using net radiation data

Abstract

The variability of surface sensible heat flux depends strongly on the heating rate of the material beneath the surface. This variability is expected to be large in urban areas where the surfaces are layered with a variety of man-made materials. Parameterization of the ground heat storage as a function of surface materials is presented based on analyses of data obtained during the U.S. Environmental Protection Agency's Regional Air Pollution Study conducted in St. Louis, Missouri. Ground heat flux data are derived from observations of surface and subsurface temperatures for a soil layer and for concrete slabs resting on soil. The data show that the presence of the concrete slabs increases the ground storage term relative to that for soil alone. The ground storage and sensible heat flux terms for a blackened concrete slab are larger than for an unpainted concrete slab. For the concrete surfaces, the ratio of ground storage to net radiation is >1 at night and <1 during the day. This ratio is discontinuous at sunrise and sunset transition periods. For soil, the ratio shows similar temporal behavior except that on average, there is a smoother transition at sunrise. Simple mathematical expressions giving the ratio of ground heat storage to net radiation as a function of time are presented.