青藏高原积雪深度时空分布与地形的关系

Relationship between the spatial and temporal distribution of snow depth and the terrain over the Tibetan Plateau

利用1979—2010年逐日中国雪深长时间序列数据集,采用GIS空间分析和Mann-Kendall检验等方法,分析了青藏高原雪深时空分布及其与地形的关系。结果表明：青藏高原雪深分布受地形影响明显,在5—9月平均雪深主要受到高程影响,在其他月份则受气温和高程共同影响;同一高程带雪深的变幅反映坡度和坡向对雪深的影响,变幅越宽坡向影响越大;最大雪深随高程和坡度的增加而增加,空间变异随高程的增加而下降,随坡度的增加而呈上升趋势;从10月至翌年5月,平均雪深在高程82-2 482 m和6 082-7 682 m受坡度和坡向影响较高程2 482-6 082 m要偏大;回归分析表明,高原雪深分布受到高程和坡度的双重影响,高程是雪深分布的主要影响因子,在高程82-3 282 m区间,坡度的空间差异对平均雪深空间变异的影响具有明显正效应。

Using the daily dataset of snow depth from 1979 to 2010 , the authors analyzed the relationship between the spatial and temporal distribution of snow depth and the terrain factors over the Tibetan Plateau by means of Mann-Kendall test and GIS space analysis. According to the results achieved, the distribution of snow depth was significantly affected by topography, the average snow depth was affected mainly by elevation from May to September, whereas in other months it was under the common influence of temperature and elevation. The snow depth amplitude of the same segment elevation reflected the impact of the aspect on snow depth, and the influence was greater when the amplitude was wider. The maximum snow depth kept increasing with the increment of elevation and slope, while the spatial heterogeneity decreased with the increment of elevation but increased with the decrement of slope. From October to May of the next year, the average snow depth at the elevation from 82 to 2 482 meter and 6 082 to 7 682 meter was more affected by slope and aspect than that at the elevation from 2 482 to 6 082 meter. Multiple regression analysis showed that the distribution of snow depth over the Tibetan Plateau was influenced by elevation and slope;furthermore, spatial differences of slope at the elevation of 82-3 282 meter had significant positive effect on the spatial variability of average snow depth; nevertheless, elevation was the main limiting factor of the average snow depth.