Isolating the Contributions of Seasonal Climate Warming to Permafrost Thermal Responses Over the Qinghai‐Tibet Plateau

Abstract

AbstractClimate warming is thermally degrading permafrost. The climate warming over the Qinghai‐Tibet Plateau (QTP) is characterized by obvious seasonality and stronger winter warming in comparison with summer warming in 2000s. The contributions of seasonal climate warming to permafrost thermal responses remain unknown. Here, we isolated the seasonal warming contributions to permafrost thermal regimes through contrasting a series of specially designed numerical experiments that were composed of decadal seasonal data segments. The results reveal that permafrost thermal regime is highly sensitive to winter temperature change. Permafrost in the Three River Source region and on the Qiangtang High Plateau has undergone remarkable thermal degradation in the 2000s due to winter warming. It was estimated that each degree of rising in air temperature in summer could lead to an average increase of 0.35 m in the active layer thickness (ALT) and of 0.20°C in the mean annual ground temperature (MAGT), while for 1° winter warming, the active layer thickens by 0.16 m and the MAGT increases by 0.13°C. However, the overall impacts of winter warming have exceeded summer warming in 2000s due to a triple warming rate in winter than that in summer in this period.