HydroThermal Dynamics of Frozen Soils on the Tibetan Plateau during 2015-2016

Abstract

The hydrothermal dynamics of frozen soil were monitored at a typical meadow ecosystem on the Tibetan Plateau. Soil temperature/moisture profiles were automatically measured at a 30-min. interval by 5TM ECH2O probes (Decagon Devices, Inc., USA) installed at the following depths: 5 cm, 10 cm, 20 cm, 40cm, and 80 cm. The turbulent heat fluxes were measured by an eddy-covariance (EC) system (LI-COR 7500, Campbell Scientific). STEMMUS-FT (Simultaneous Transfer of Energy, Mass and Momentum in Unsaturated Soil with Freeze-Thaw process) model, with two control experiments (Ctrl1 for Van Genuchten hydraulic scheme and Ctrl2 for Clapp and Hornberger hydraulic scheme), was employed to reproduce the simultaneous movement of soil moisture and heat flow in the frozen soil. With the aid of physically based STEMMUS-FT model and in situ measurements, we can investigate the underlying mechanisms of the water and heat transfer in frozen soils