论文部分内容阅读
以黄河源区多年冻土分布现状和热力特征为研究目标,通过野外调查及实测数据,分析了黄河源区不同地形地貌、不同地表覆盖条件下的冻土形成、分布特征和以地温为基础的热学特征,探讨了不同尺度因素对多年冻土分布的影响。结果表明,在高程低于4 300 m的平原区,多年冻土多不发育;在高于4 350 m的山区,局地地形对多年冻土的形成与分布作用显著。除阳坡地形外,多年冻土均比较发育;介于4 300~4 350 m的低山丘陵和平原区,局地地形、地表植被、土壤湿度等因素共同决定着多年冻土的形成和分布格局。以年均地温指标为基础,构建了以纬度、经度和高程为自变量的回归模型,并对阳坡地形进行微调和校正。结果表明,以0oC作为划分季节冻土和多年冻土的标准和界限,多年冻土面积2.5×104km2,约占整个源区面积的85.1%;季节冻土面积0.3×104km2,约占整个源区面积的9.7%。进一步以0.5oC或1.0oC为分类间隔绘制了黄河源区多年冻土热稳定性空间分布图。
Taking the distribution and thermal characteristics of the permafrost in the source region of the Yellow River as the research objective, the formation and distribution of permafrost under different land-cover conditions and on the basis of ground temperature were analyzed through field surveys and measured data. Thermal characteristics of the impact of different scales on the distribution of permafrost. The results show that the permafrost is undeveloped in the plains where the elevation is below 4 300 m. In the mountainous areas above 4 350 m, the topography has a significant effect on the formation and distribution of permafrost. Besides permafrost topography, the permafrost is relatively developed. In the hilly and plains area of 4300 ~ 4350 m, the formation and distribution of permafrost are determined by local topography, surface vegetation, soil moisture and other factors pattern. Based on the average annual temperature index, a regression model with latitude, longitude and elevation as independent variables was constructed, and the terrain of the sunny slope was fine-tuned and corrected. The results show that 0oC is the standard and boundary for dividing seasonal permafrost and permafrost. The permafrost area is 2.5 × 104km2, accounting for 85.1% of the total area of the source area. The area of seasonal frozen soil is 0.3 × 104km2, 9.7% of the area. Further, the spatial distribution map of the thermal stability of the permafrost in the source region of the Yellow River was plotted at 0.5oC or 1.0oC intervals.