Physical Linkage Between Sensible and Ground Heat Flux

Abstract:

Partitioning solar radiation to latent (E), sensible (H) and ground (G) heat fluxes controls terrestrial energy and water cycles. The G-H relationship has remained poorly understood mainly because the turbulent flow processes driving H is fundamentally different from those of laminar flow driving G. We indicate, however, that the average behavior of the turbulent heat diffusion at daily and longer timescales is analogous to the laminar heat flow driven by combined diffusion and advection processes. Accordingly, we employ a linearized advection-diffusion model to decode both G and H fluxes solely from a sequence of land surface temperature data. This new approach reveals a linear relationship between the daily G and H terms. This relationship provides a new constraint on the surface energy balance equation that can potentially reduce the uncertainties in its closure at various spatial scales.