降雨事件特征对季节性冻土水热状态的影响OA

Under the ongoing warming and humidification trend on the Qinghai-Xizang Plateau,the influence of rainfall on the hydrothermal conditions of frozen soil has become increasingly significant.To investigate the ef-fects of rainfall characteristics on the hydrothermal state of seasonally frozen soil,this study analyzed the respons-es of frozen soil hydrothermal conditions under varying rainfall regimes based on continuous in-situ monitoring of meteorological variables and soil hydrothermal dynamics in Riwoqê County.The results indicate that the study ar-ea is dominated by short-duration(0 h＜H≤6 h)and small-amount(0.1 mm≤P≤9.9 mm)events,accounting for 57.81%and 84.39%of the total,respectively.Under similar rainfall amounts(7.6 mm≤P≤8.1 mm),short-du-ration events during the thawing period accelerates cooling of the 0～15 cm soil layer(by 11.13%～81.49%)and reduces heating of the 25～35 cm layer(by 18.18%～85.07%),while longer events primarily mitigate tempera-ture changes.Short-duration rainfall also produces the largest increase in soil moisture(average 6.90%at 5～35 cm),though the rates of increase and decrease generally decline with rainfall duration.Under comparable du-rations(10 h≤H≤13 h),heavy rainfall induces rapid cooling in the 0～25 cm soil layer and slight warming at 35～45 cm(1.0℃and 0.8℃,respectively),whereas lighter rainfall mainly weakens temperature variation.Small,short-duration events(H≤5 h,P≤5 mm)slowed temperature change with minimal effects below 15 cm,and soil moisture exhibits greatest increases during the complete thawing period(0.59%at 2.5～15 cm)while smallest during complete freezing period.Overall,rainfall typically had a cooling effect,as theoretical rainwater temperatures were consistently lower than surface soil temperatures(hourly temperature difference was-1.57～30.99℃,daily average temperature difference was 0.45～15.86℃),particularly from June to August.