Validation of two soil heat flux estimation techniques against observations made in an engineered urban green space

In highly developed landscapes, the soil heat flux that results from changes in land cover determines, in part, the extent to which urban climatic conditions can be modulated (e.g. retrofitting cities with new, engineered green spaces to reduce urban heat island effect). In this paper, temperature-dependent (TD) and temperature-independent (TI) soil heat flux models are validated against 6 days of measurements made in an engineered urban green space. The results suggest that the TI model (heat flux plate method) represents the observations better than the temperature-dependent one, which consistently overestimates soil heat flux at night and during the dusk-dawn period. Moreover, a sensitivity analysis reveals that the TD model is more sensitive to the selection of thermal conductivity and heat capacity values than the TI model. It can be concluded that the TI model is a more robust predictive tool, and especially in urban applications where soil properties may be highly uncertain.