Changes of frozen ground since 1980s under climatic warming on the Qinghai-Tibet Plateau

The frozen ground, including permafrost and seasonally frozen ground, is underlain in the majority of the Qinghai-Tibet Plateau. The changes of frozen ground have great influence on the local hydrology and water resources, ecosystem, and infrastructure stability in cold regions. The Changes of frozen ground are important, but relatively rarely reported, indicators of climate change. In this study we summarize recent research on the changes of frozen ground carried out on the Qinghai-Tibet Plateau, based on the statistical analysis of observations and the review of previous literatures. The results indicate that permafrost degradation has been occurring during the last decades as following changes, thickening of active layer, rising of ground temperature, even disappearing of sporadic permafrost. At the same time, the seasonally frozen ground has suffered great changes such as the decrease of maximum frozen depth and the decrease of frozen days during the freeze-thaw cycles. The warming trend would last in the following years and the greater changes in frozen ground would exert great impacts on the environment in this sensitive regions.