The effect of precipitation-induced advective heat on permafrost in the Tibetan PlateauFigshare

Study region: The Tibetan Plateau (TP), China, contains the world’s largest permafrost area outside the Polar Regions. Study focus: This study investigates the precipitation-induced advective heat flux (EPre), which represents the energy transfer resulting from the temperature difference between rainfall and soil. Observational data from three permafrost monitoring sites (Qumalai, Xidatan, and Tanggula) were combined with simulations from the Community Land Model version 5.0 (CLM5.0) to quantify EPre precipitation infiltration depth, and the probability of infiltration reaching the frozen soil layer. The analysis further examines how precipitation amount, soil texture, soil moisture, and freeze–thaw state jointly control infiltration processes and influence the soil thermal regime. New hydrological insights for the region: Infiltration depth varies with initial soil moisture and precipitation duration, from shallow retention to deep percolation. EPre is generally negative, with maximum cooling of −84.14 W m⁻² at QML, −73.24 W m⁻² at XDT, and −56.63 W m⁻² at TGL, but becomes positive during prolonged summer rainfall, reaching 45.43 W m⁻² at QML. Diurnal soil temperature variations shift EPre from cooling by day to reduced cooling or warming at night. Across the TP, mean infiltration depth is ∼5 cm, higher in southeastern Tibet, with a regional mean EPre of −0.08 W m⁻². Warming effects are concentrated in the southeastern and central TP, while cooling dominates the arid west and high-elevation north.