Sensitivity of thermal parameters affecting cold-region ground-temperature predictions

Abstract

This study formulates a heat-flux upper boundary to model ground temperatures in the Qinghai-Tibet plateau. This model considers the impacts of the environmental conditions, e.g., air temperature, ground-surface albedo, wind speed, and solar radiation on the ground-surface heat flux and on subsequent subsurface temperature profiles. It speculates that in arid regions, neglecting the evaporation-induced heat flux does not compromise the ground-temperature predictions notably. The predicted results are validated by the observed temperature profiles at a test station on the Qinghai-Tibet plateau. A temperature-controlled upper boundary model is also utilized to simulate the ground-temperature profile and is compared to the same field-observed temperature profiles. A sensitivity study is conducted to characterize the influence of local weather conditions on the ground-temperature development. Conditions considered include mean annual air temperature, seasonal air temperature amplitude, daily air temperature variation, mean annual wind speed, seasonal wind-speed variation, and daily wind-speed fluctuation. The sensitivity study also considers effects of variations the ground-surface albedo on the ground-temperature development and on the ground thermal re-equilibrium. It finally presents the implication of this re-equilibrium on the specified initial ground-temperature profile.