The Qinghai-Tibet Plateau (QTP) has the largest extent of high altitude permafrost at the middle and low latitudes in northern hemisphere and is surrounded by dozens of seasonally frozen ground. Rising air temperatures have resulted in frozen ground degradation over QTP since the last century. Based on the daily frozen soil depth, annual mean daily minimum air temperatures and annual mean air temperatures obtained from 19 in-situ observations over QTP, the changes in the thickness, temporal and spatial distributions of frozen ground, as well as the associated attributions, are analyzed for the period of 1960–2019. The results show that the maximum depth of frost penetration, the beginning time of soil freezing and the ending time of soil thawing have changed considerably. On average, the maximum depth of frost penetration (MDFP) has reduced by 0.14∼1.71 m at most stations. The annual frozen period has decreased by about 40 days. The changes in seasonal freezing of soils appear to be attributed to the rising of minimum air temperatures in winter, especially at the higher elevations range from 4500 to 5000 m.

青藏高原（QTP）在北半球的中低纬度地区具有最高的高海拔多年冻土层，周围有数十个季节性冻土。自上个世纪以来，气温升高导致QTP地面冻结。根据每天的冻土深度，年平均日最低气温和从19中获得的年平均气温原位对1960-2019年期间QTP的观测资料，冻土厚度，时空分布的变化以及相关的归因进行了分析。结果表明，霜冻渗透的最大深度，土壤冻结的开始时间和土壤融化的结束时间都发生了很大变化。平均而言，大多数站点的最大霜冻渗透深度（MDFP）降低了0.14〜1.71 m。每年的冻结期减少了约40天。土壤季节性冻结的变化似乎归因于冬季最低气温的升高，特别是在海拔从4500至5000 m的较高海拔地区。