Permafrost is an important part of the cryosphere, playing an integral role in the hydrologic cycle, ecology, and influencing human activity. Melting of ground ice can drastically change landscapes and associated thaw subsidence may induce instability of infrastructure. The terrain conditions on the Qinghai-Tibet Plateau are complex, and the spatial distribution of ground ice is highly variable, so knowledge of its abundance and variability is required for impact assessments relating to the degradation of permafrost. This study examined 55 permafrost samples from warm, ice-rich permafrost region in Beiluhe Basin, Qinghai-Tibet Plateau. The samples were examined using Computed Tomography scanning, and the ice content and cryostructure were determined. The results indicated that: 1) variation in volumetric ice content was considerable (0%-70%), with a mean value of 17%; 2) seven cryostructures were identified, including crustal, vein, lenticular, ataxitic, reticulate and layered cryostructure; 3) volumetric ice content varied by cryostructure, with the highest associated with layered and ataxitic cryostructures. Volumetric ice contents were lowest for samples with pore and lenticular cryostructures. This work provides detailed ground ice content and will be helpful for assessing thaw subsidence and infrastructure stability on Qinghai-Tibet Plateau.

The excess ice content of near-surface permafrost near Barrow, Alaska, was estimated using cores collected from 57 drained thermokarst-lake basins and additional cores from a nearby landform unaffected by thaw-lake processes. The excess ice content, estimated using soil cryostructures, increased with surface age: from 20 per cent in young basins?