Abstract:

Based on frozen soil active layer data and 0 cm ground temperature data at 83 weather stations in Heilongjiang province from 1960 to 2010, temporal and spatial characteristics of frozen soil active layer were analyzed using liner and polynomial regression analysis methods. Change trend of the maximum frozen soil depth and its characteristics were discussed for five typical climate region of Heilongjiang province, and the influencing factors of frozen soil active layer were analyzed. The results indicate that the early date of soil becoming frozen begins in September. The maximum depth of frozen soil appears in March, while thickness of frozen soil is nearly 0 cm in August. From north to south in Heilongjiang province, the maximum frozen soil depth becomes shallow gradually; the early date of soil frozen is delayed; the ending date of frozen soil occurs early. The maximum frozen soil depth of active layer is in a decreasing trend in Heilongjiang province, and the degradation trend is obvious. For the interdecadal change, the maximum frozen soil depth has not a significant change before 1990s, while thickness of frozen soil is deeper; it is in a decreasing trend after 1990s. The ground?temperature is lower in high latitude regions, thus frozen soil depth is deeper in high latitude regions than in low latitude regions under the same conditions.

Key words: Frozen soil, Active layer, Trend