研究人员通过观测被称为泥炭丘的小丘来测量永冻带边界北退的程度，泥炭丘是在北部泥炭沼泽含冰的土壤上自然形成的。

The researchers measured the retreat of the permafrost border byobserving hummocks known as "palsas, " which form naturally over icecontained in the soil of northern peat bogs.

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土壤水分在全球水资源中所占的比列很小，存储在土壤空隙中的水分仅占全球水资源0.005%，但它是水文模型和气候模型的重要边界条件。

Although soil moisture constitutes only about 0.005 % of the global water resources, it's important as a boundary condition for hydrologic and climate models.

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通过对土壤和铀尾矿的具体计算，表明两种边界条件下的计算结果有较大的偏差。

The results show that there is a relatively large deviation for calculating results under two kinds of boundary conditions.

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