Impact of Climate Change on frozen soil parameterization in the Source Region of Yellow River

Observational evidence indicates that climate warming has been well underway in the source region of Yellow River for the past few decades. Under a warming climate, permafrost has thinned or, in some areas, has totally disappeared. The changes of frozen soil not only influence the climate system, but also impact water resources, and ecological environment. On the other hand, current hydrological models are unable to well take account of frozen soil parameterization. Based on the daily ground temperature data and the actual observed freeze-thaw depth data from July 1st 2006 to June 30th 2008 of 15 stations in the source region of Yellow River, a mathematical model for solving the problem of coupled moisture and heat transfer during soil freezing is established in this study to simulate frozen-thaw processes. The numerical model successful simulated the frozen soil parameterization. Making use of the data which is predicted with GCMs, the freeze-thaw depth is simulated in the source region. The tendency of the frozen soil change for the future multi-decades has also been estimated in the source region of Yellow River in this study. The study results indicate that the freeze-thaw cycles will change correspondingly with increasing temperature in different stations. The freeze-thaw cycles were about 6 months in the first two years. However, the cycles become short after that. Also as air temperature increases, the maximum freezing depth will decrease.