Quantitative evaluation of characteristic precipitation event (CPE)’s effect on hydro-thermal state of active layer in Beiluhe area

The climate change is significantly changing the hydro-thermal state of active layer at Qinghai–Tibet Plateau (QTP), which endangers permafrost environment. The degradation of permafrost would damage the linear engineering in cold regions; furthermore, the alternation of soil hydro-thermal state in the area of rugged terrain would lead to geo-hazards and then threaten the safety of local people. Global warming is widely accepted as a big threat to the ecological environment of arctic, subarctic and alpine regions, while the changing trend of precipitation around the world is still in dispute. Furthermore, the role of precipitation accompanied with global warming is unknown. Hence, in this study, the localized monitoring data from Beiluhe permafrost monitoring station at QTP, including atmospheric and soil hydro-thermal data, were utilized for further processing and comparative analysis. Firstly, the changing trend of precipitation here was investigated through the atmospheric data from 2003 to 2013. Thereafter, the hydro-thermal change of active layer was analyzed combined with precipitation events during this period. However, the raining pattern in QTP is characterized with continuity, short duration and small amount, basically referring to thawed season. The hydro-thermal change affected by corresponding raining event could be influenced by temporally nearby event in timescale. To differentiate the effect, the characteristic precipitation event (CPE) was selected through an elaborate algorithm. Subsequently, the hydro-thermal changes of active layer were reanalyzed in response to CPEs. Representative outcomes were chosen for the specific analysis under the influence from CPEs. Hence, under the circumstance of global warming, the effect from precipitation on the hydro-thermal properties of active layer was also obtained, and the possible harmful consequence induced by that was also discussed. Graphic abstract