共查询到10条相似文献，搜索用时 140 毫秒
1.
Studies on frozen ground of China 总被引：5，自引：0，他引：5
1ThestatusoffrozengroundinChinaBased on previous studies, Zhou and Guo (1982) summarized the distribution characteristics of permafrost in China and indicated that the permafrost area in China is about 215×104 km2, in which about 163.4×104 km2 is on the Tibetan Plateau. After mapping and zonation of frozen ground in 1983, Xu and Wang suggested that the areas of permafrost, seasonally frozen ground and temporal frozen ground in China were 206.8×104 km2, 513.7×104 km2 and 229.1×104 km2 … 相似文献
2.
Permafrost in China includes high latitude permafrost in northeastern China, alpine permafrost in northwestern China and high plateau permafrost on the Tibetan Plateau. The high altitude permafrost is about 92% of the total permafrost area in China. The south boundary or lower limit of the seasonally frozen ground is defined in accordance with the 0 oC isothermal line of mean air temperature in January, which is roughly corresponding to the line extending from the Qinling Mountains to the Huaihe River in the east and to the southeast boundary of the Tibetan Plateau in the west. Seasonal frozen ground occurs in large parts of the territory in northern China, including Northeast, North, Northwest China and the Tibetan Plateau except for permafrost regions, and accounting for about 55% of the land area of China. The southern limit of short-term frozen ground generally swings south and north along the 25o northern latitude line, occurring in the wet and warm subtropic monsoon climatic zone. Its area is less than 20% of the land area of China. 相似文献
3.
At present, gas hydrates are known to occur in continental high latitude permafrost regions and deep sea sediments. For middle latitude permafrost regions of the Tibetan Plateau, further research is required to ascertain its potential development of gas hydrates. This paper reviewed pertinent literature on gas hydrates in the Tibetan Plateau. Both geological and ge- ographical data are synthesized to reveal the relationship between gas hydrate formation and petroleum geological evo- lution, Plateau uplift, formation of permafrost, and glacial processes. Previous studies indicate that numerous residual basins in the Plateau have been formed by original sedimentary basins accompanied by rapid uplift of the Plateau. Ex- tensive marine Mesozoic hydrocarbon source rocks in these basins could provide rich sources of materials forming gas hydrates in permafrost. Primary hydrocarbon-generating period in the Plateau is from late Jurassic to early Cretaceous, while secondary hydrocarbon generation, regionally or locally, occurs mainly in the Paleogene. Before rapid uplift of the Plateau, oil-gas reservoirs were continuously destroyed and assembled to form new reservoirs due to structural and thermal dynamics, forcing hydrocarbon migration. Since 3.4 Ma B.P., the Plateau has undergone strong uplift and extensive gla- ciation, periglacier processes prevailed, hydrocarbon gas again migrated, and free gas beneath ice sheets within sedi- mentary materials interacted with water, generating gas hydrates which were finally preserved under a cap formed by frozen layers through rapid cooling in the Plateau. Taken as a whole, it can be safely concluded that there is great temporal and spatial coupling relationships between evolution of the Tibetan Plateau and generation of gas hydrates. 相似文献
4.
近30年来青藏高原西大滩多年冻土变化 总被引：32，自引：1，他引：31
结合1975年已有勘探资料,对青藏高原多年冻土北界西大滩进行了雷达勘探。勘探发现,近30年来青藏高原多年冻土北界发生较大规模的多年冻土退化,多年冻土面积从1975年的160.5 km2退化成现在的141.0 km2,缩小约12%;开始出现多年冻土的最低高程为4 385 m,比1975年升高了25 m。近30年来研究区的气候变化是造成北界多年冻土退化的主要原因。相同气候背景下,多年冻土腹部地温有升高,但在30年尺度上不会发生明显的退化。本次冻土区域调查的结果可为检验冻土－气候关系模型的可靠与否提供依据。 相似文献
5.
《自然地理学》2013,34(4):279-298
Although soil freeze/thaw phenomena were reported centuries ago in the historical Chinese literature, systematic study of permafrost in China started in the 1950s. Permafrost research in China has been related to the exploration for and economic development of natural resources. Intensive investigations for several decades culminated in 2000 in the publication of a detailed map of geocryological regionalization and classification. From this map, it is estimated that permafrost covers approximately 23% of the country. About 80% of China's permafrost is mountain permafrost. China contains about 74.5% of the mountain permafrost area of the northern hemisphere. Since the early 1960s, researchers in China have conducted numerous field campaigns to determine permafrost and ground-ice distribution. A comprehensive ground-based and long-term monitoring network has been established on the Tibetan Plateau and in northeastern China. The State Key Laboratory of Frozen Soil Engineering (SKLFSE) was established in 1991 and is open to national and international engineers and scientists to conduct related studies and experiments. Numerous field and laboratory experiments, as well as numerical modeling, have been conducted to meet the requirements for industrial design, construction, and operation in permafrost regions. Rescuing, archiving, and distributing historical permafrost data would greatly aid the ability of scientists to assess long-term changes in permafrost and its potential influence on the natural and engineered environment. Chinese geocryologists and engineers are facing new challenges with the construction and future operation of the Qinghai-Xizang railroad that will cross 550 km of permafrost on the Tibetan Plateau. 相似文献
6.
Research on the relationship between national resource constraint-region types and environmental carrying capacity is essential for the continued development of Chinese industrialization and urbanization. Thus, utilizing a series of key indexes including the per-capita potential of available land resources, the per-capita potential of available water resources, the degree of environmental stress, and the degree of ecological restriction, a step-by-step, integrated measuring method is presented here to understand the constrained carrying elements of water and land resources as well as environment and ecology. Spatial differences are analyzed and area types classified at the county level across China. Results reveal that: (1) Almost 90% of China is strongly constrained by both resources and the environment, while nearly 50% of national territory is strongly constrained by two elements, especially in areas of intensive population and industry to the east of the Helan-Longmen Mountain line; (2) Densely populated areas of eastern and central China, as well as on the Tibetan Plateau, are strongly constrained by a shortage of land resources, while North China, the northwest, northeast, the Sichuan basin, and some southern cities are experiencing strong constraints because of water shortages. In contrast, the North China plain, the Yangtze River delta, northern Jiangsu, Sichuan province, Chongqing municipality, Guizhou and Guangxi provinces, the northeast plain, and the northern Loess Plateau are constrained by high levels of environmental stress. Areas of China that are strongly ecologically constrained tend to be concentrated to the southwest of the Tianshan-Dabie Mountain line, as well as in the northeast on the Loess Plateau, in the Alashan of Inner Mongolia, in northeast China, and in the northern Jiangsu coastal area; (3) Constraints on national resources and environmental carrying capacity are diverse and cross-cut China, meanwhile, multi-element spatial distribution does reveal a degree of relative centralization. With the exception of the Tibetan Plateau which is resources-ecological constraint , other areas subject to cross constraints are mainly concentrated to the east of the Helan-Longmen Mountain line. 相似文献
7.
黄河源区冻土分布制图及其热稳定性特征模拟 总被引：5，自引：0，他引：5
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。 相似文献
8.
9.
论青藏高原范围与面积 总被引：84，自引：4，他引：80
长期以来 ,种种因素导致学者们对青藏高原确切范围的认识和理解存在差异。根据青藏高原相关领域研究的新成果和多年野外实践 ,从地理学角度 ,充分讨论了确定青藏高原范围和界线的原则与涉及的问题 ,结合信息技术方法对青藏高原范围与界线位置进行了精确的定位和定量分析。得出 :青藏高原在中国境内部分西起帕米尔高原 ,东至横断山脉 ,横跨 31个经度 ,东西长约 2 94 5km ;南自喜马拉雅山脉南缘 ,北迄昆仑山 -祁连山北侧 ,纵贯约 13个纬度 ,南北宽达 15 32km ;范围为 2 6°0 0′12″N～ 39°4 6′5 0″N ,73°18′5 2″E～ 10 4°4 6′5 9″E ,面积为 2 5 72 4× 10 3km2 ,占我国陆地总面积的 2 6 8%。 相似文献