State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Science, Lanzhou, 730000, China.
Sci Rep. 2017 May 8;7(1):1544. doi: 10.1038/s41598-017-01787-0.
Desertification of tundra regions may form an escalating cycle with permafrost degradation where more permafrost thaw leads to continued desertification. This traditional viewpoint has been challenged in recent reports that state desertification protects the underlying permafrost. However, our measurements of soil temperature from nine sites in the Honglianghe River Basin, interior Qinghai-Tibet Plateau, show that desertification can degrade permafrost. If one compares the permafrost temperatures at sites with thin sand covers (e.g. site Yu-7, permafrost temperature of -0.64 °C; site Yu-6, permafrost temperature of -1.15 °C) with that of site Xie-1 (-0.65 °C, with a 120-cm-thick sand cover), the permafrost temperature is not significantly different. It is clear that a thick sand cover does not influence the underlying permafrost temperature. Our observations support traditional geocryological knowledge which states that, under most circumstances, desertification does not protect, but rather degrades, permafrost.
苔原地区的荒漠化可能与永久冻土退化形成一个不断升级的循环，即更多的永久冻土融化会导致持续的荒漠化。最近的一些报告挑战了这一传统观点，称荒漠化可以保护下面的永久冻土。然而，我们对青藏高原腹地红梁河流域的九个地点的土壤温度进行的测量显示，荒漠化可能会使永久冻土退化。如果将沙层较薄的地点（例如，Yu-7 点，永久冻土温度为-0.64°C；Yu-6 点，永久冻土温度为-1.15°C）与 Xie-1 点（有 120 厘米厚沙层，永久冻土温度为-0.65°C）的永久冻土温度进行比较，就会发现沙层厚度并没有显著影响下面的永久冻土温度。这清楚地表明，厚厚的沙层不会影响下面的永久冻土温度。我们的观测结果支持传统的地质冰川学知识，即大多数情况下，荒漠化不会保护永久冻土，而是会使永久冻土退化。
