若尔盖高原及其周围山地的冻土和环境

Frozen Ground and Environment in the Zoige Plateau and Its Surrounding Mountains

若尔盖高原内部年平均气温０．６～３．３℃，气温年较差１９．１～２１．２℃，已不具备多年冻土形成和保存的气候条件。据１９９２年７月间试坑和钻孔测温，在１．０～２．２ｍ深处地温为５～８．４℃，浅层地下水温６．０～７．８℃，由此判断不存在多年冻土，季节冻结深度为１．０～２．０ｍ。据冻土现象和试坑资料判断，周围山地海拔４１５０～４２００ｍ以上发育山地岛状多年冻土。区内沼泽演化表明，部分沼泽已疏干或向疏干趋势发展，草场退化和草原沙化已成为本区生态环境的重要问题。

Field investigation shows no permafrost in the interior of the Zoige Plateau. The mean annual air temperature is 0.6～3.3℃, and the annual range of air temperature is 19.1～21 2℃ . It is not cold enough to form permafrost. According to the temperature measurement from pits and boreholes (in July 1992), the ground temperature is 5 0～8 4℃ in the depth of 1 0～2 2 m, and shallow ground water temperature is 6 0～7 8℃. The seasonal frozen depth is 1 0～2 0 m. Permafrost has formed above 4150～4200 m a.s.l. in the mountainous around the plateau according to a permafrost investigation and pit prospecting. The swamp evolution reveals that a part of swamp has been drained and another part will be drained. The degeneration and desertification of grass lands becomes an important problem to ecological environment, impacts livestock.