snow limit

As the zero-balanced surface of rainfall, the snowline can be defined as the lower limit of the perennially snow-covered area, and it is a geographic element as important as the tree line, the periglacial line and the soil line.

雪线是降水的零平衡面，作为终年积雪区的下界，是与林线、冰缘线和土壤线等界线同等重要的自然地理区划线。

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Finally, combine these three methods to determine the slope length limit of longitudinal ground road under snow and ice conditions.

最后结合上述三种方法确定冰雪条件下地面道路的纵坡坡长限制指标。

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