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。
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 .
冰缘线