Quantified spatial-temporal variation of the fine-scale frozen soils during 1980–2014 in the headwaters of the Yellow River (HWYR) in High Mountain Asia

•Estimated permafrost degradation using coupled hydro-thermal dynamics model WaSiM.•Permafrost degraded from DPT increasing, bottom rising and ended with decreasing MFD.•PA decreased at a rate of −7105 km2/decade (-5.8 %/decade) and DPT 31.76 cm/decade.•AMFD decreased at −14.47 cm/decade, TD −5.56 days/decade and NFD −9.97 days/decade.•Changing rates of ADPT and AMFD close to 0 when AT trend smaller than 0.55 °C/decade.