Research on Influencing Factors of Freezing and Thawing Process in the regions over 5000 m a.s.l

The freezing and thawing process is a unique feature of the alpine permafrost ecosystem, which controls growth microorganisms meadows, plays vital role in animal husbandry development, ecosystem functions services. Meanwhile, also affected by external environmental factors, its spatial differences are very significant, especially regions over 5000 m a.s.l. In this study, periods Cuoma Township (CM), Xiangmao (XM) Xiaotanggula Mountain (XTGL) sites Nagqu River Basin divided, effects altitude, vegetation coverage, air temperature, organic matter content on analyzed, main influencing factors discussed. results show that a.s.l, thaw initiation period (TIP) starts early April, entirely thawed (ETP) end May, freeze (FIP) October, frozen (EFP) November. Compared with below FIP EFP a.s.l start earlier, TIP later rate faster. Organic factor during EFP, temperature ETP. This study helpful to clarify changes provides theoretical support for ecological protection restoration.