Impact of frozen soil processes on soil thermal characteristics at seasonal to decadal scales over the Tibetan Plateau and North China

Abstract. Frozen soil processes are of great importance in controlling surface water and energy balances during the cold season regions. Over recent decades, considerable frozen degradation warming have been reported over Tibetan Plateau North China, but most land models difficulty capturing freeze–thaw cycle, few validations focus on effects thermal characteristics these This paper addresses issues by introducing a physically more realistic computationally stable efficient module (FSM) into model – third-generation Simplified Simple Biosphere Model (SSiB3-FSM). To overcome difficulties achieving numerical solutions for soil, new semi-implicit scheme physics-based freezing–thawing were applied to solve governing equations. The performance this as well process temperature profile investigated China using observation sites from Meteorological Administration 1981 2005. Results show that SSiB3 with FSM produces its seasonal variation than without freezing thawing periods. delays winter cooling, while summer warming. time lag amplitude damping become pronounced increasing depth. These simulated SSiB3-FSM. could increase phase days memory at different depths change thickness. Furthermore, compared observations, SSiB3-FSM maximum depth decadal scales. study shows scales ground can be greatly improved SSiB3-FSM, used an effective TP NC simulation season. Overall, help understand vertical provide important scientific basis land–atmosphere interactions.