What is freeze-thaw desertification?

Freeze-thaw desertification is the structural destruction or quality degradation of rock mass or soil due to strong thermal expansion and cold contraction in areas with large temperature difference between day and night or season. The area of freeze-thaw desertification land in China is * * * 366,000 square kilometers, accounting for 13.8% of the total area of desertification land. Freeze-thaw desertification land is mainly distributed in the high altitude areas of the Qinghai-Tibet Plateau, with sporadic distribution in a few high mountain areas in Gansu and the upper reaches of Jinsha River and its tributaries in Batang, Derong and Xiangcheng counties of Sichuan on the north side of Hengduan Mountains, but the area is not too large.