Freezing-thawing rule of seasonal frozen soil and its eco-hydrological function in Zhalong Wetland

In Zhalong Wetland, the seasonal frozen soil distributes extensively, which plays a crucial role in the eco-hydrological processes. The freezing and thawing processes are analyzed based on the location observation of the soil temperature from the first automatic monitoring station our country constructed, and the freezing and thawing characteristics are obtained. In addition, by analyzing the data, such as runoff, precipitation and so on, the eco-hydrological function for the wetland of the frozen soil is discussed. The results show that the soil begins to freeze around October 20 and the depth of frozen soil maximizes in March of the next year, and the frozen soil begins to melt around March 5, finishes melting around May 20 of the next year; the frozen soil is the key factor influencing the eco-hydrological processes, and the frozen backwater is indispensable, even is unique water resources for the natural and artificial plants to live through winter and multiply in springtime, and is the predominant factor that keeps the ecosystem balance and promotes the salinization and swampiness.