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1.
青藏高原工程走廊多年冻土是地气系统相互作用的产物,气候环境决定了其分布的宏观格局,但局地因素如坡向等,在一定条件下,对小区域多年冻土的影响往往会超过大气候背景。通过Pearson相关性分析,选取了对青藏高原工程走廊多年冻土分布影响较大、在GIS技术支持下较容易量化的坡向,结合区域内29个钻孔点的长期地温监测数据,建立了年平均地温与高程、纬度及坡向之间的多元线性模型。根据青藏高原冻土工程地温分带指标,制作出了走廊内符合实际的冻土分布图。运用随气候变化的响应模型,预测了走廊内50 a后多年冻土将发生较大的变化:1.低温稳定区、低温基本稳定区的空间分布面积逐渐减小,分布界线向高海拔迁移;2.高温不稳定区较大范围地向高温极不稳定区转化;3.高温极不稳定区将处于长期的退化过程。 相似文献
2.
基于分区和多元数据的青藏高原温泉区域多年冻土分布研究 总被引：3，自引：1，他引：2
以野外勘探、室内理论分析与建模为主要研究方法,以数字高程模型(GDEM)和实测数据为基础进行统计分析,发现坡向对多年冻土分布具有重要影响。针对青藏高原温泉区域地形的复杂性,基于分区的方法将研究区分为平原区和山区两个地形区。对于平原区来说,考虑到苦海湖泊对多年冻土的影响,将苦海滩地单独划出并采用专家知识完成冻土制图,其余平原区采用建立的地温模型进行冻土制图;对于山区来说,通过定量化研究坡向对冻土地温的影响建立了基于坡向调整作用下的地温模型,应用此模型完成了山区的冻土分布图。以地温作为冻土类型划分的依据,分析了研究区域冻土的空间分布与特征,结果表明:多年冻土的分布面积为1 681.4km2,占整个区域的66.7%,其中,过渡型和亚稳定型多年冻土为主要多年冻土类型,两者占整个研究区域的50.8%,其次为不稳定型多年冻土(11.4%),稳定型和极稳定型多年冻土的面积比例相对较小(4.4%和0.2%)。从空间分布格局来看,冻土分布具有明显的垂直分带特征,随着海拔高度的升高,冻土地温逐渐降低,冻土类型依次经历季节冻土-不稳定型多年冻土-过渡型多年冻土-亚稳定型多年冻土-稳定型多年冻土-极稳定型多年冻土的变化。 相似文献
3.
青藏高原西部区域多年冻土分布模拟及其下限估算 总被引：3，自引：0，他引：3
准确评估青藏高原西部多年冻土的空间分布及多年冻土下限深度情况对该区地下水资源利用、生态环境保护有重要意义.本文依托科技基础性工作专项“青藏高原多年冻土本底调查”在该区及周边取得的冻土调查资料,利用遥感数据和扩展地面冻结数模型模拟了该区多年冻土的空间分布,调查区的模拟验证表明该方法有较高的精度.在此基础上,根据有限的地温实测资料建立了地温与位置、高程、坡向和太阳辐射的关系,并根据地温-下限关系估算了该区多年冻土下限深度的分布情况.研究表明,该区有多年冻土约占36.9%,季节冻土占57.5%,多年冻土主要分布在34°N~36.5°N范围的喀喇昆仑、西昆仑一带,季节冻土主要分布在塔里木盆地和34°N以南地区.阿里高原及以南是岛状多年冻土分布区域,其多年冻土分布面积少于此前出版的冻土图所绘制的.青藏高原西部区域的多年冻土下限深度整体表现为由东南-西北逐渐加深. 相似文献
4.
青藏高原风火山地区冻土变化分析 总被引：1，自引：0，他引：1
基于对多年来风火山地区的多年冻土资料,研究了天然地区和路基下的冻土上限变化情况以及多年冻土的融化状态,并定量分析了进入多年冻土内的热状况。结果表明：风火山地区从20世纪70年代到90年代中期冻土上限下降,冻土出现退化现象,从90年代至今冻土趋于稳定；路基近地表地温明显高于对应天然地表下的地温,路基近地表经历的融化期长于对应天然地表,进入多年冻土区的热收支也呈现出吸热明显大于放热的周期性变化,进入多年冻土的热积累暂时以增高地温耗热为主,但随着冻土吸热量的逐年积累、冻土温度的不断升高,本区冻土可能发生强烈融化。 相似文献
5.
黄河源区多年冻土空间分布变化特征数值模拟 总被引：3，自引：1，他引：2
基于IPCC第五次评估报告预估的气温变化情景,采用数值模拟的方法对黄河源区典型冻土类型开展模拟,推算过去及预测未来黄河源区冻土分布空间变化过程和发展趋势。结果表明：1972-2012年源区多年冻土只有少部分发生退化,退化的冻土面积为833 km2,季节冻土主要集中在源区东南部的热曲谷地、小野马岭以及两湖流域南部的汤岔玛地带;RCP 2.6、RCP 6.0、RCP 8.5情景下,2050年多年冻土退化为季节冻土的面积差别不大,分别为2224 km2、2347 km2、2559 km2,占源区面积的7.5%、7.9%、8.6%;勒那曲、多曲、白马曲零星出现季节冻土,野牛沟、野马滩以及鄂陵湖东部的玛多四湖所在黄河低谷大片为季节冻土;2100年多年冻土退化为季节冻土的面积分别为5636 km2、9769 km2、15548 km2,占源区面积的19%、32.9%、52.3%;星宿海、尕玛勒滩、多格茸的多年冻土发生退化,低温冻土变为高温冻土,各类年平均地温出现了不同程度的升高。到2100年,RCP 2.6情景下源区多年冻土全部退化为季节冻土主要发生在目前年平均地温高于-0.15 oC的区域,而-0.15~-0.44 oC的区域部分发生退化;RCP 6.0、RCP 8.5情景下目前年平均地温分别为高于-0.21 oC以及-0.38o C的区域多年冻土全部发生退化,而-0.21~-0.69 oC以及-0.38~-0.88 oC的区域部分发生退化。 相似文献
6.
青海省柴达尔-木里地区道路沿线多年冻土分布模拟 总被引：3，自引：0，他引：3
以青海省柴达尔-木里铁路、热水-江仓公路沿线两侧约10 km缓冲区为研究区域,以冻土钻孔实测数据为基础,定量分析和评价了经度、纬度、高程、太阳辐射、坡度、坡向、地面曲率等地形-候因子对沿线区域多年冻土分布的影响,建立了以经度、高程、坡度为自变量、多年冻土发生概率为因变量的Logistic模型.借助于GIS软件和DEM数据,完成了道路沿线区域多年冻土分布概率图的绘制和多年冻土分布概率的特征分析.结果表明,极可能多年冻土(概率值为0.75～1)的分布面积为1983 km2,占整个研究区域面积的65%;可能多年冻土(概率值为0.5～0.75)的分布区面积为192 km2,占研究区域面积的6%;季节冻土(概率值＜0.5)的分布区面积为894 km2,占沿线区域面积的29%. 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.
黄河源区多年冻土温度及厚度研究新进展 总被引：5，自引：0，他引：5
利用新布设的冻土孔及原有冻土资料,分析黄河源区冻土温度和厚度的空间分布。源区实测多年冻土年均地温最低为-1.81℃,冻土最厚74 m,均位于巴颜喀拉山北坡的查拉坪。214国道(K445-K604段)沿线多为高温多年冻土(年均地温>-1℃),但巴山北坡海拔4 520 m、布青山海拔4 300 m以上,年均地温低于-0.5℃。巴山北坡海拔4 610 m、布青山海拔4 420 m以上,年均地温低于-1℃。巴山北坡海拔每升高100 m,年均地温减少0.47~0.75℃,冻土厚度增加16~25 m;纬度向北增加1°,年均地温减少0.85℃,冻土厚度增加20~30 m。 相似文献
9.
未来气候变暖情形下青藏高原多年冻土分布初探 总被引：4，自引：0，他引：4
基于未来温室气体中等排放情景下气候模式给出的气候预测结果的高分辨率降尺度分析结果,运用两种方法(年均温法和高程模型法)模拟了1980-1999,2030-2049和2080-2099年3个时段青藏高原多年冻土分布.结果表明,以年均地温-1℃作为多年冻土划分依据的年均温法模拟的目前(1980-1999年)高原多年冻土面积为127.99万km2,与世界数据中心给出的青藏高原现代多年冻土面积为129.12万km2的估算接近(误差率仅为0.86%);到本世纪中期(2030-2049年),高原多年冻土面积减少为87.26万km2,退化率达到31.82%;而到本世纪末(2080-2099年),高原多年冻土面积只有69.25万km2,较目前将退化45.89%.不同高度带的对比分析还发现,与高原及其邻近地区年均气温的升高一般随海拔高度而增加的趋势相反,未来高原多年冻土的退化率将随着海拔高度增加而降低.在全球变暖过程中的冻土退化,特别是高原东南部冻土向西北部的逐步退缩,对高原冻土区工程稳定性的影响应引起我们的足够重视. 相似文献
10.
由于泥炭化冻土是冻土工程建设中需要解决的重大问题,因此泥炭与冻土的共生关系备受关注。以川西高原0~30 cm深度的泥炭化冻土为研究对象,从泥炭化冻土的形成和泥炭与冻土的共生关系角度,选取控制因素,分析这些因素的控制机制,并将这些因素作为评价指标;采用熵权法、层次分析法和模糊评价方法,制作出川西高原泥炭化冻土分布图;最后,结合前人的相关研究成果对研究结果进行了验证。研究结果表明,采用的研究方法具有可行性;川西高原泥炭化冻土分布具有区域聚集、空间变异性大和受纬度地带性影响大的特点;高泥炭化冻土的面积为0.8×10^(4) km^(2)(约占研究区面积的5%),中泥炭化冻土的面积为7.8×10^(4) km^(2)(约占研究区面积的33%);低泥炭化冻土广泛分布,面积为11.5×10^(4) km^(2)(约占研究区面积的50%);非泥炭化冻土面积为3.0×10^(4) km^(2)(约占研究区面积的12%);多年冻土的泥炭化程度最大;冻土与泥炭的共生作用对冻土工程具有显著影响。 相似文献
11.
青藏高原盐湖赋存着丰富的钾资源元素。近年来,在全球变暖和大规模人工开发背景下,青藏高原盐湖卤水钾含量和矿化度发生显著变化。系统对比了青藏高原31个盐湖近年来和1990s之前卤水的钾离子含量和矿化度变化情况,分析其主要影响因素。结果显示,近年来青藏高原盐湖钾离子含量和矿化度总体呈现下降趋势,但不同盐湖变化程度不同;藏北高原、可可西里高原、西昆仑等地区盐湖主要受气候-构造-水文等自然因素影响,钾离子和矿化度下降明显;柴达木盆地盐湖受资源开发和人为干预等因素影响,卤水钾离子含量下降,而矿化度略有增加。 相似文献
12.
可可西里盐湖湖水外溢可能性初探 总被引：5，自引：0，他引：5
2011年9月可可西里地区卓乃湖溃决后,关于盐湖湖水能否外溢进入楚玛尔河继而成为长江的最北源是公众及学界普遍关注的话题。本研究基于2010-2015年Landsat TM/ETM+/OLI遥感影像、SRTM 1弧秒数据、Google Earth高程数据和五道梁气象台站观测数据,首次对盐湖变化、湖水外溢条件及其可能性进行分析。结果表明：卓乃湖溃决后,盐湖在2011年10月至2013年4月期间面积急剧增加,之后湖泊进入稳定扩张期,2015年10月27日盐湖面积为151.38 km2,是2010年3月3日湖泊面积的3.35倍。盐湖发生湖水外溢的条件是湖泊面积达到218.90~220.63 km2。由于SRTM和Google Earth高程数据间的差异,盐湖湖水外溢时的水位将比当前高12 m或9.6 m,相应湖泊库容增加23.71 km3或17.27 km3,届时湖水将由湖泊东侧流入清水河流域。尽管盐湖在未来10年内不可能发生湖水外溢,但是随着盐湖集水区的扩大及预估的区域未来降水量的增加,在更长时间尺度内盐湖发生湖水外溢并成为长江支流的可能性依然存在。 相似文献
13.
DING Mingjun ZHANG Yili SHEN Zhenxi LIU Linshan ZHANG Wei WANG Zhaofeng BAI Wanqi ZHENG Du 《地理学报》2006,16(4):387-395
Based on the NOAA AVHRR-NDVI monthly data from 1981 to 2001, the spatial distribution and dynamic change of land cover along the Qinghai-Tibet Highway and Railway were studied. The results of the analytical data indicate that the NDVI values in July, August and September are rather high during a year, and a linear trend by calculating NDVI of each pixel computed based on the average values of NDVI in July, August and September were obtained. The results are as follows: 1) Land cover of the study area by NDVI displays high at two sides of the area and low in the center, and agriculture area > alpine meadow > alpine grassland > desert grassland. 2) In the study area, the amount of pixels with high increase, slight increase, no change, slight decrease and high decrease account for 0.29%, 14.86%, 67.61%, 16.7% and 0.57% of the whole area, respectively. The increase of land cover pixels is mainly in the agriculture and alpine meadow and the decrease pixels mainly in the alpine grassland, desert grassland and hungriness. Grassland and hungriness contribute to the decrease mostly and artificial land and meadow contribute to the increase mostly. 3) In the area where human beings live, the changing trend is obvious, such as the valleys of Lhasa River and Huangshui River and area along the Yellow River; in the high altitude area with fewer people living, the changing trend is relatively low, like the area of Hoh Xil. 4) Human being’s behaviors are a key factor followed by the climate changes affecting land cover. 相似文献
14.
Xiaojun Yao Meiping Sun Peng Gong Baokang Liu Xiaofeng Li Lina An Luxia Yan 《地理学报(英文版)》2018,28(5):647-655
After the bursting of Huiten Nor in Hoh Xil Region in September, 2011, the topic on whether the water overflowed from the Salt Lake would enter into the Chumaer River and become the northernmost source of the Yangtze River has aroused wide concern from public and academic field. Based on Landsat TM/ETM+/OLI remote sensing images during 2010–2015, SRTM 1 arc-second data, Google Earth elevation data and the observation data from the Wudaoliang meteorological station, the study initially analyzed the variations of the Salt Lake and its overflowing condition and probability. The results showed that the area of the Salt Lake expanded sharply from October 2011 to April 2013, and then it stepped into a stable expansion period. On October 27, 2015, the area of the Salt Lake had arrived at 151.38 km2, which was about 3.35 times the area of the lake on March 3, 2010. The Salt Lake will overflow when its area reaches the range from 218.90 km2 to 220.63 km2. Due to the differences between SRTM DEM and Google Earth elevation data, the water level of the Salt Lake simulated would be 12 m or 9.6 m higher than the current level when the lake overflowed, and its reservoir capacity would increase by 23.71 km3 or 17.27 km3, respectively. Meanwhile, the overflowed water of the Salt Lake would run into the Qingshui River basin from its eastern part. Although the Salt Lake does not overflow in the coming decade, with watershed expansion of the Salt Lake and the projected precipitation increase in Hoh Xil region, the probability of water overflow from the Salt Lake and becoming a tributary of the Yangtze River will exist in the long term. 相似文献
15.
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
16.
中国冻土研究进展 总被引：6，自引：0，他引：6
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 ℃ 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 25° 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
17.
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
18.
By large-scale dynamic tests carried out on a traditional sand-gravel embankment at the Beilu River section along the Qinghai-Tibet Railroad, we collected the acceleration waveforms close to the railway tracks when trains passed. The dynamic train loading was converted into an equivalent creep stress, using an equivalent static force method. Also, the creep equation of frozen soil was introduced according to the results of frozen soil rheological triaxial tests. A coupled creep model based on a time-hardening power function rule and the Druker-Prager yield and failure criterion was established to analyze the creep effects of a plain fill embankment under repeated train loads. The temperature field of the embankment in the permafrost area was set at the current geothermal conditions. As a result, the permanent deformation of the embankment under train loading was obtained, and the permanent deformation under the train loads to the total embankment deformation was also analyzed. 相似文献