Page 55 - 《高原气象》2025年第5期

5 期 李博渊等：青藏高原多年冻土冻融参量时空变化特征及影响因子研究 1173
February and May. Semi-humid regions have the longest thawing duration， whereas semi-arid regions have the
shortest， with an average difference of 15 days. The freeze-thaw status of permafrost soil on the plateau exhibits
significant changes. Except for areas near the Karakoram Mountains， most permafrost regions show a decreasing
trend in freezing duration and an increasing trend in thawing duration. The average growth rate of soil thawing
duration across the plateau is 2 d·（10a）⁻¹， with the most significant increase observed in semi-humid regions，
reaching 4 d·（10a）⁻¹.（2） The freeze-thaw parameters of the plateau's permafrost are associated with geographi‐
cal factors. In the latitude range of 29°N -36°N and longitude range of 82. 5°E -103°E， the thawing duration
shows an increasing trend； however， the rate of change decreases in some areas while increasing in others. Addi‐
tionally， as elevation increases， the growth rate of thawing duration declines.（3） The duration of permafrost
thawing is significantly correlated with snow depth， near-surface temperature， precipitation， and vegetation in‐
dex， though these relationships vary across different climatic regions. Near-surface temperature exhibits a strong
positive correlation across all regions， making it the primary driver of freeze-thaw changes. Precipitation and
snow depth show positive and negative correlations， respectively， with particularly strong correlations in semi-
humid areas. The vegetation index is positively correlated with thaw duration in all regions， with the strongest
correlation observed in semi-arid areas.（4） The relationship between thawing duration and seasonal climatic fac‐
tors varies. Near-surface air temperature exerts a significant influence on the freeze-thaw process at seasonal
scales， with the most pronounced impact occurring in spring. Precipitation is positively correlated in summer but
negatively correlated in winter. Both snow depth and vegetation index are significantly correlated with thawing
duration in semi-arid and semi-humid regions during spring， exhibiting negative and positive correlations， re‐
spectively.（5） Near-surface temperature influences the freeze-thaw cycle in the plateau’s perennial permafrost
region during both dry and wet seasons. However， the effects of snow depth， precipitation， and vegetation index
are more pronounced during the wet season.
Key words： Qinghai-Xizang（Tibetan）Plateau； permafrost； freeze-thaw cycles； numerical modeling； climate
change