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多年冻土对青藏高原草地生态承载力的贡献研究 预览
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作者 方一平 朱付彪 +2 位作者 宜树华 邱孝枰 丁永建 《气候变化研究进展》 CSCD 北大核心 2019年第2期150-157,共8页
草地生态系统是一个复杂的社会、经济、生态系统,多年冻土作为高寒草地生态系统结构和功能维系的重要因素,是客观刻画高寒草地生态承载力不容忽视的重要方面。文中采用结构动力学方法,从草地质量、草地干预、草地潜力、草地压力4个维度... 草地生态系统是一个复杂的社会、经济、生态系统,多年冻土作为高寒草地生态系统结构和功能维系的重要因素,是客观刻画高寒草地生态承载力不容忽视的重要方面。文中采用结构动力学方法,从草地质量、草地干预、草地潜力、草地压力4个维度建立高寒草地生态承载力结构动力学模型,分析青藏高原多年冻土区草地生态承载力的变化以及主要结构要素,量化多年冻土变化对青藏高原高寒草地生态承载力的贡献率,结果表明:(1)多年冻土区草地生态承载力呈增加趋势,尤其是1998年以后上升显著,这主要归因于草地生长季节降水增加、气温升高、净初级生产力增幅驱动以及生态保护工程建设的共同作用。(2)多年冻土活动层厚度变化与草地生态承载力呈负相关,多年冻土活动层厚度对草地生态承载力的贡献率约为10%,即多年冻土活动层厚度每增加1个单位,将导致草地生态承载力下降0.1个单位。由于青藏高原空间差异显著,加之气候变化的不确定性,这一贡献水平只是一个粗略的参照值。 展开更多
关键词 草地生态承载力 多年冻土 多年冻土活动层厚度 结构动力学 青藏高原
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机械式制冷热管对多年冻土的制冷效果研究 预览
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作者 赵永虎 崔雍 +2 位作者 米维军 韩龙武 熊治文 《铁道标准设计》 北大核心 2019年第1期34-39,共6页
多年冻土区路基防护技术是冻土科研人员长期研究的重点。基于多年冻土区现场试验,对研发的新型机械式制冷热管与普通热管的制冷效果进行对比分析。结果表明:(1)机械式制冷热管可以弥补普通热管在暖季不能工作的缺陷,能在暖季和寒季同时... 多年冻土区路基防护技术是冻土科研人员长期研究的重点。基于多年冻土区现场试验,对研发的新型机械式制冷热管与普通热管的制冷效果进行对比分析。结果表明:(1)机械式制冷热管可以弥补普通热管在暖季不能工作的缺陷,能在暖季和寒季同时带走活动层中的热量,增加冷储量,有效保护多年冻土;(2)分别在寒季和暖季,机械式制冷热管比普通热管的侧壁温度在活动层中低2.77~0.39℃、1.22~0.13℃,在多年冻土层2.0~6.0m深度范围中低3.24~0.52℃、0.55~0.12℃,机械式制冷热管年均温度比普通热管年均温度在活动层和多年冻土层中均低0.74℃;(3)分别在暖季和寒季,机械式制冷热管的积温是普通热管积温的1.4倍~2.1倍、1.4倍~1.8倍,机械式制冷热管的年积温是普通热管年积温的1.9倍。研究成果可为新型机械式制冷热管技术在多年冻土热稳定维护中的应用提供理论依据。 展开更多
关键词 多年冻土 机械式制冷热管 热管 制冷效果 地温 冻土上限 现场试验
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Role of permafrost in resilience of social-ecological system and its spatio-temporal dynamics in the source regions of Yangtze and Yellow Rivers
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作者 FANG Yi-ping ZHU Fu-biao +2 位作者 YI Shu-hua QIU Xiao-ping DING Yong-jian 《山地科学学报:英文版》 SCIE CSCD 2019年第1期179-194,共16页
Permafrost is one of the key components of terrestrial ecosystem in cold regions.In the context of climate change,few studies have investigated resilience of social ecological system(SER)from the perspective of permaf... Permafrost is one of the key components of terrestrial ecosystem in cold regions.In the context of climate change,few studies have investigated resilience of social ecological system(SER)from the perspective of permafrost that restricts the hydrothermal condition of alpine grassland ecosystem.In this paper,based on the structural dynamics,we developed the numerical model for the SER in the permafrost regions of the source of Yangtze and Yellow Rivers,analyzed the spatial-temporal characteristics and sensitivity of the SER,and estimated the effect of permafrost change on the SER.The results indicate that:1)the SER has an increasing trend,especially after 1997,which is the joint effect of precipitation,temperature,NPP and ecological conservation projects;2)the SER shows the spatial feature of high in southeast and low in northwest,which is consistent with the variation trends of high southeast and low northwest for the precipitation,temperature and NPP,and low southeast and high northwest for the altitude;3)the high sensitive regions of SER to the permafrost change have gradually transited from the island distribution to zonal and planar distribution since 1980,moreover,the sensitive degree has gradually reduced;relatively,the sensitivity has high value in the north and south,and low value in the south and east;4)the thickness of permafrost active layer shows a highly negative correlation with the SER.The contribution rate of permafrost change to the SER is-4.3%,that is,once the thickness of permafrost active layer increases 1 unit,the SER would decrease 0.04 units. 展开更多
关键词 RESILIENCE of social ecological system PERMAFROST PERMAFROST active layer thickness Structural dynamic equation Source REGIONS of YANGTZE and YELLOW RIVERS
青海祁连山冻土区天然气水合物研究进展综述
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作者 王平康 祝有海 +6 位作者 卢振权 白名岗 黄霞 庞守吉 张帅 刘晖 肖睿 《中国科学:物理学、力学、天文学》 CSCD 北大核心 2019年第3期76-95,共20页
祁连山冻土区是我国陆域天然气水合物调查研究的重点地区之一,也是我国目前在陆域冻土区唯一一处取得天然气水合物找矿发现的地区.自2008年首次钻获天然气水合物实物样品以来,调查研究工作逐步向广度和深度迈进,取得了由点到面的扩边勘... 祁连山冻土区是我国陆域天然气水合物调查研究的重点地区之一,也是我国目前在陆域冻土区唯一一处取得天然气水合物找矿发现的地区.自2008年首次钻获天然气水合物实物样品以来,调查研究工作逐步向广度和深度迈进,取得了由点到面的扩边勘查进展、油气等多种能源的发现以及试采试验成功等系列成果,同时基础理论认识水平得到了显著提升.在水合物地质特征和成藏系统研究方面,各要素描述得更加全面和深入,尤其是对气源和构造条件的深入分析,进一步丰富了水合物含油气系统的内涵.在调查技术方法研究方面,通过开展试验性实验,初步形成了从点上钻探调查技术到面上地球物理-地球化学调查综合性的技术方法体系,在勘探实践中发挥了重要的作用.在水合物试采试验方面,证实了降压试采工艺、控制监测等关键技术在成岩储层中应用的可行性,提出水平井试采工艺结合储层压裂改造技术将是未来提高产气量重要的科技攻关方向之一.在环境效应研究方面,发现了可以证实水合物稳态发生过变化或正处于变化之中的矿物学证据,提出了气候变暖引起水合物系统的演变模式,环境影响作用已逐步显现.由此可见,在祁连山冻土区,天然气水合物具有资源与环境并重的双重意义,不仅作为一种新型能源具有潜在的资源价值,而且还是一种会引起环境效应的不稳定因素.不难预测,随着青藏高原持续变暖,水合物储层稳定性评价研究将成为祁连山冻土区水合物资源环境效应研究的一个重要方面. 展开更多
关键词 天然气水合物 冻土区 研究进展 祁连山 青海
考虑降雨作用的气温升高对多年冻土活动层水热影响机制
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作者 张明礼 温智 +5 位作者 董建华 王得楷 侯彦东 王斌 郭宗云 魏浩田 《岩土力学》 EI CAS CSCD 北大核心 2019年第5期1983-1992,共10页
近50 a青藏高原暖湿化趋势显著,水热边界条件的改变必然影响多年冻土的稳定性和高原生态环境的演变。已有研究主要关注气候升温对冻土温度场的影响,而对升温过程伴随的活动层水分变化研究较少。基于土壤-地表-大气水分和能量平衡的冻土... 近50 a青藏高原暖湿化趋势显著,水热边界条件的改变必然影响多年冻土的稳定性和高原生态环境的演变。已有研究主要关注气候升温对冻土温度场的影响,而对升温过程伴随的活动层水分变化研究较少。基于土壤-地表-大气水分和能量平衡的冻土水-汽-热耦合模型,以青藏高原北麓河地区2013年实测气象资料为模型驱动数据,研究在降雨不变,气温不变、气温升高1℃和升高2℃情况下活动层水热响应机制与过程。结果表明:气候升温通过改变地表能量与水分平衡过程和土壤内部水热运移分量影响多年冻土水热过程。气温升高引起地表净辐射、蒸发潜热和土壤热通量增大,而地表降雨入渗和感热通量减少;气温升高会降低土壤含水率和土壤导水系数,但温度梯度及与温度梯度相关的水分和能量分量相应增大,而与水势梯度相关的水分和能量分量相对减少;升温对土壤温度场的影响比水分场明显,影响范围也更深;随着气温升高,地表蒸发量和活动层厚度增大,气温升高加速了冻土的退化过程,与降雨增加对冻土的热稳定性影响相反。 展开更多
关键词 多年冻土 活动层 水分运移 热传递 气候变化 降雨
碎石层反射率模型及其运用研究 预览
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作者 梁若婵 张信贵 +1 位作者 谭康豪 李芳华 《长江科学院院报》 CSCD 北大核心 2019年第2期111-115,121共6页
阴阳坡效应对寒区道路工程建设质量和后期运营养护都有十分重要的影响,因此对边坡稳定技术的研究和创新成为当下的热点。在碎块石护坡表面喷涂浅色材料或高反射材料,将提高路基边坡的反辐射能力,从而可以大幅度减小地表接收的净辐射和... 阴阳坡效应对寒区道路工程建设质量和后期运营养护都有十分重要的影响,因此对边坡稳定技术的研究和创新成为当下的热点。在碎块石护坡表面喷涂浅色材料或高反射材料,将提高路基边坡的反辐射能力,从而可以大幅度减小地表接收的净辐射和增强块碎石层的冷却效果。通过建立碎石粗糙表面能量吸收模型,推导出碎石粗糙表面的宏观反射率R与微观反射率r之间的关系。借助于图像处理分析方法,准确分析碎石和孔洞区域的面积,据此估算碎石层的反射率,并利用实测数据验证模型的可靠性。对模型参数进行分析发现:降低块石表面粗糙度和近地面空隙度有利于提高整个碎石层的反射率;碎石表面的粗糙度抑制了宏观反射率R的提高;涂料的最佳选择要根据碎石层粗糙程度决定,建议选择涂料反射率在0.4~0.6为宜。 展开更多
关键词 碎石层 阴阳坡效应 多重反射 反射率 粗糙度 图像处理 多年冻土
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多年冻土区宽幅路基温度与变形规律试验研究
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作者 陈冬根 朱英珍 《公路》 北大核心 2019年第2期1-7,共7页
为研究黑色沥青路面吸热对多年冻土区宽幅路基的热影响问题,以共和~玉树公路宽幅路基为原型,进行了室内模型试验,研究了多次冻融循环作用下沥青路面吸热对宽幅路基温度场与变形分布影响。研究结果表明:经过3个冻融循环周期的运行,沥青... 为研究黑色沥青路面吸热对多年冻土区宽幅路基的热影响问题,以共和~玉树公路宽幅路基为原型,进行了室内模型试验,研究了多次冻融循环作用下沥青路面吸热对宽幅路基温度场与变形分布影响。研究结果表明:经过3个冻融循环周期的运行,沥青路面下伏土体温度逐渐升高,具体表现在0℃等温线位置出现明显下降,其中,第一周期融化结束时路中部位0℃等温线处于72cm深度位置,第二周期融化结束时0℃等温线处于39cm深度位置,第三周期结束时路中部位冻土几乎全部消失;沥青路面吸热导致冻土融化产生变形,经历3次冻融循环以后路中顶面、左路肩顶面变形量依次达到49.92mm、43.24mm;路基变形分布中饱冰冻土层变形占总变形比例最大,其次为浅地表层变形,最后为路基填土变形。 展开更多
关键词 多年冻土 宽幅路基 冻融循环 温度 变形
江源冻土区水循环研究进展 预览
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作者 覃自成 常福宣 《水利科学与寒区工程》 2019年第1期59-65,共7页
在气候变化背景下,江源冻土区水循环和生态系统发生改变,引发的水文、环境、工程问题受到广泛关注。本文从国内外江源冻土区水循环特征、水文模拟的相关研究、气候变化对江源冻土区产生的影响三个方面展开论述。总结了江源冻土区水循环... 在气候变化背景下,江源冻土区水循环和生态系统发生改变,引发的水文、环境、工程问题受到广泛关注。本文从国内外江源冻土区水循环特征、水文模拟的相关研究、气候变化对江源冻土区产生的影响三个方面展开论述。总结了江源冻土区水循环特点,模拟了关键之处以及气候变化带来的利害,最后提出了江源冻土区的研究趋势和对发展方向的展望。 展开更多
关键词 江源区 冻土 水循环 水文模拟 气候响应
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Dynamic changes in lakes in the Hoh Xil region before and after the 2011 outburst of Zonag Lake
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作者 LIU Wen-hui XIE Chang-wei +6 位作者 ZHAO Lin WU Tong-hua WANG Wu ZHANG Yu-xin YANG Gui-qian ZHU Xiao-fan YUE Guang-yang 《山地科学学报:英文版》 SCIE CSCD 2019年第5期1098-1110,共13页
Zonag, Kusai, Hedin Noel and Yanhu Lakes are independent inland lakes in the Hoh Xil region on the Qinghai-Tibet Plateau. In September2011, Zonag Lake burst after the water level had increased for many years. Floods f... Zonag, Kusai, Hedin Noel and Yanhu Lakes are independent inland lakes in the Hoh Xil region on the Qinghai-Tibet Plateau. In September2011, Zonag Lake burst after the water level had increased for many years. Floods flowed through Kusai and Hedin Noel Lakes into Yanhu Lake;since then, the four small endorheic catchments merged into one larger catchment. This hydrological process caused the rapid shrinkage of Zonag Lake and continuous expansion of Yanhu Lake. In this study,based on satellite images, meteorological data and field investigations, we examined the dynamic changes in the four lakes and analyzed the influencing factors. The results showed that before 2011, the trends in the four lake areas were similar and displayed several stages. The change in the area of Zonag Lake corresponded well to the change in annual precipitation(AP), but the magnitude of the change was less than that of a non-glacier-fed lake. Although increased precipitation was the dominant factor that caused Zonag Lake to expand, increased glacier melting and permafrost thawing due to climate warming also had significant effects. After the 2011 outburst of Zonag Lake, due to the increasing AP and accelerating glacier melting, the increases in water volume of the three lakes were absorbed by Yanhu Lake, and Yanhu Lake expanded considerably. According to the rapid growth rates in water level and lake area, Yanhu Lake is likely to burst in 1-2 years. 展开更多
关键词 Dynamic CHANGE LAKE areas Influencing factors GLACIER CHANGE PERMAFROST thawing Zonag LAKE
Modeling the carbon dynamics of alpine grassland in the Qinghai-TibetanPlateau under scenarios of 1.5 and 2 ℃ global warming 预览
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作者 YI Shu-Hua XIANG Bo +2 位作者 MENG Bao-Ping WU Xiao-Dong DING Yong-Jian 《气候变化研究进展:英文版》 CSCD 2019年第2期80-91,共12页
Alpine grassland occupies two-thirds of the Qinghai-Tibetan Plateau (QTP). It is vital to project changes of this vulnerable ecosystem under different climate change scenarios before taking any mitigation or adaptatio... Alpine grassland occupies two-thirds of the Qinghai-Tibetan Plateau (QTP). It is vital to project changes of this vulnerable ecosystem under different climate change scenarios before taking any mitigation or adaptation measures. In this study, we used a process-based ecosystem model, driven with output from global circulation models under different Representative Concentration Pathways (RCPs), to project the carbon dynamics of alpine grassland. The results showed the following: 1) Vegetation carbon (C) on the QTP increased by 22—38 gC m^-2 during periods of 1.5 and 2 ℃ warming under different RCPs when compared to the baseline period (1981—2006), while soil C increased by 85—122 gC m^-2. 2) The increases of vegetation C and soil C at the period of 1.5 ℃ warming were about 15 gC m^-2 and 40 gC m^-2 smaller than those at the period of 2 ℃ warming, respectively;increase of C was greater for alpine meadow than for alpine steppe. 3) Precipitation, radiation, and permafrost changed significantly and showed heterogeneous spatial patterns, and caused heterogeneous response of C dynamics. For alpine meadow in regions transformed from permafrost to seasonally frozen soil with medium annual precipitation (200—400 mm), vegetation C and net primary production decreased by 18.7 gC m-2 and 3.1 gC m^-2 per year during 2 °C warming under RCP 4.5, respectively. This decrease can be attributed to the disappearing impermeable permafrost. Different from previous studies that indicated an unfavorable response of alpine grassland to climate warming, this study showed a relatively favorable response, which is mainly attributed to C 0 2 fertilization. 展开更多
关键词 PERMAFROST TERRESTRIAL ECOSYSTEM model VEGETATION Soil Net primary production
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An ecosystem services zoning framework for the permafrost regions of China 预览
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作者 XU Ling-Xing YANG De-Wei +6 位作者 WU Tong-Hua YI Shu-Hua FANG Yi-Ping XIAO Cun-De LIN Hao-Xi HUANG Jin-Chuan Claudien HABIMANA SIMBI 《气候变化研究进展:英文版》 CSCD 2019年第2期92-98,共7页
The degradation of the permafrost regions, resulting from intensive anthropogenic activities and global warming, has led to the loss of ecosystem services and is threating human well-being. Nevertheless, the real ecos... The degradation of the permafrost regions, resulting from intensive anthropogenic activities and global warming, has led to the loss of ecosystem services and is threating human well-being. Nevertheless, the real ecosystem service values and their complete zoning system in the permafrost regions have received insufficient attention. Research gaps between the identification of permafrost-based ecosystem services and ecosystem management are seriously constraining the development of cryospheric science. Thus, an ecosystem service zoning framework that links ecosystem services with human welfares is proposed to solve the abovementioned challenges in the permafrost regions of China. The three tiered zoning framework for ecosystem services, consisting of zoning goals, principles, hierarchy, methodology, and nomenclature, is proposed for the permafrost regions of China. A combined method, i.e., GIS spatial tools, the location entropy analysis model, and ecosystem services assessment, was employed to distinguish ecosystem conditions, ecosystem service supply, and beneficiaries into these three-grade ecosystem service zones. Hierarchical and dynamic zoning could clarify protection priorities of ecosystems and ecosystem services in terms of regions, grades, and types. The framework could contribute to sustainable management of ecosystem services in the cryosphere. 展开更多
关键词 DEMAND ECOSYSTEM services ECOLOGICAL ZONING PERMAFROST Supply
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Impact of climate change on allowable bearing capacity on theQinghai-Tibetan Plateau 预览
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作者 XU Xiao-Ming WU Qing-Bai 《气候变化研究进展:英文版》 CSCD 2019年第2期99-108,共10页
Climate change has a substantial impact on infrastructures in the permafrost on the Qinghai-Tibetan Plateau (QTP). In this study, the mean annual ground temperature (MAGT) and permafrost evolution were investigated in... Climate change has a substantial impact on infrastructures in the permafrost on the Qinghai-Tibetan Plateau (QTP). In this study, the mean annual ground temperature (MAGT) and permafrost evolution were investigated in both the historical (1950-2005) and projected (2006-2099) periods. Then, an allowable bearing capacity model was used to discuss the allowable bearing capacity change on the QTP. Results show that the MAGT increased by 0.36 ℃ during 1950-2005. The MAGT will increase by 0.40 (RCP2.6), 0.79 (RCP4.5), 1.07 (RCP6.0), and 1.75 (RCP8.5)℃C during 2006-2099. In addition, the permafrost area has decreased by 0.195 × 10^6 km2 in 1950-2005. The permafrost area will decrease by 0.232 × 10^6 (RCP2.6), 0.468 × 10^6 (RCP4.5), 0.564 × 10^6 (RCP6.0), and 0.803 × 10^6 (RCP8.5) km2 during 2006-2099. With the degradation of permafrost, the allowable bearing capacity in permafrost zones would decrease accordingly. The decreasing trend is 6 kPa per 10 years in 1950-2005, and will be 0.6 (RCP2.6), 5 (RCP4.5), 7 (RCP6.0), and 11 (RCP8.5) kPa per 10 years during 2006-2099. The most remarkable trend would be observed under RCP8.5. Meanwhile, some scientific advices for the design, construction, operation and maintenance of permafrost engineering in the context of climate change were provided. 展开更多
关键词 Qinghai-Tibetan PLATEAU CLIMATE CHANGE PERMAFROST Allowable BEARING capacity
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高原寒区多年冻土抗侵彻性能数值模拟研究
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作者 马军平 谭仪忠 +3 位作者 王昱蘅 张俊海 陈昊 张枫 《防护工程》 2019年第1期25-30,共6页
针对高原寒区多年冻土环境中的地下工程防护问题,在考虑冻土特性和环境对冻土性能的影响基础上,对多年冻土的抗侵彻性能进行了数值模拟研究。依据冻土分布和力学基本性能,考虑温度梯度对冻土抗剪指标的影响,采用LS-DYNA有限元法建立了... 针对高原寒区多年冻土环境中的地下工程防护问题,在考虑冻土特性和环境对冻土性能的影响基础上,对多年冻土的抗侵彻性能进行了数值模拟研究。依据冻土分布和力学基本性能,考虑温度梯度对冻土抗剪指标的影响,采用LS-DYNA有限元法建立了高原寒区多年冻土层的抗侵彻计算模型。弹体和靶板分别采用J-C和D-P模型,并加入失效准则使模型更加贴近侵彻实际。通过数值模拟并对比理论计算和经验公式,认为冻土温度的连续性变化对冻土抗侵彻性能的影响较为显著,与前期理论计算结果较吻合,可为高原寒区地下工程建设的防护计算提供理论依据。 展开更多
关键词 多年冻土 抗侵彻 数值模拟 有限元法
青藏铁路北麓河段路基冻土动力参数试验分析 预览
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作者 高德领 班航 渠继鑫 《人民珠江》 2019年第6期71-76,共6页
冻土动力参数即是进行工程设计的依据,同时还为动力响应模拟提供必要参数。选取青藏铁路沿线粉质黏土为研究对象,通过试验分析了在不同的温度、围压、频率作用下冻土动弹性模量、动剪切模量、阻尼比的变化特性。利用等效黏弹性模型将动... 冻土动力参数即是进行工程设计的依据,同时还为动力响应模拟提供必要参数。选取青藏铁路沿线粉质黏土为研究对象,通过试验分析了在不同的温度、围压、频率作用下冻土动弹性模量、动剪切模量、阻尼比的变化特性。利用等效黏弹性模型将动弹性模量(或动剪切模量)、动阻尼比与动应变幅值之间的关系具体化,并将以上函数曲线与Hardin双曲线进行拟合,确定等效黏弹性模型中的试验参数。试验发现,冻土动弹性模量与动剪切模量随温度的降低而升高,随围压、频率的升高而升高;动阻尼比随着温度降低而降低,随着围压升高而升高,随频率升高而降低。 展开更多
关键词 多年冻土 动力参数 动弹性模量 动剪切模量 动阻尼比
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Global warming weakening the inherent stability of glaciers and permafrost
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作者 Yongjian Ding Shiqiang Zhang +2 位作者 Lin Zhao Zhongqin Li Shichang Kang 《科学通报:英文版》 SCIE EI CSCD 2019年第4期245-253,共9页
The Cryosphere has been undergoing a worldwide retreat, as seen in the decrease in the areal extent and volume of glaciers and in the areal extent of permafrost. This paper prese nts a systematic exami nation of the i... The Cryosphere has been undergoing a worldwide retreat, as seen in the decrease in the areal extent and volume of glaciers and in the areal extent of permafrost. This paper prese nts a systematic exami nation of the inherent stability changes of glaciers and permafrost caused by warming. Various study results suggest that over the past 30 years, the internal temperature of glaciers and permafrost exhibits an overall accelerating warming trend. The warming rate peaked in the mid-2000s and slowed slightly for several years afterward. In recent years, however, the warming rate has seemed to pick up again. The warming of glaciers and permafrost has exerted great impact on their stability, displayed as intensified melting, increased glacier surging, enlargement of supraglacial lakes, and increased permafrost degradation. Even without a future temperature increase, some glaciers will continue to shrink, and the number of surging glaciers will increase. The transition from low-temperature to high-temperature permafrost is a noticeable warning sign of a comprehensive degradation of permafrost. These results indicate that "warming” glaciers and permafrost will exert significant impacts on the hydrology, ecology, and stability of engineering in cold regions. 展开更多
关键词 WARMING Englacial temperature PERMAFROST INTERNAL thermal state STABILITY
青藏高原某公路沿线多年冻土特征分析及治理措施
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作者 王智明 郑胜章 《勘察科学技术》 2019年第3期24-28,共5页
该文通过对青藏高原某公路沿线分布的多年冻土的类型、发育特征及几种典型的灾害进行了分析,对不同的冻土类型,采用不同方案进行治理,并根据青藏高原多年冻土区的特点,提出了“宁填勿挖”的治理措施。对多年冻土区工程建设具有借鉴意义。
关键词 多年冻土 分布特征 灾害类型 治理方案
Evolution of permafrost in China during the last 20 ka
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作者 Huijun JIN Xiaoying JIN +8 位作者 Ruixia HE Dongliang LUO Xiaoli CHANG Shaoling WANG Sergey S MARCHENKO Sizhong YANG Chaolu YI Shijie LI Stuart A HARRIS 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第8期1207-1223,共17页
The formation and evolution of permafrost in China during the last 20 ka were reconstructed on the basis of large amount of paleo-permafrost remains and paleo-periglacial evidence, as well as paleo-glacial landforms, ... The formation and evolution of permafrost in China during the last 20 ka were reconstructed on the basis of large amount of paleo-permafrost remains and paleo-periglacial evidence, as well as paleo-glacial landforms, paleo-flora and paleofauna records. The results indicate that, during the local Last Glacial Maximum(LLGM) or local Last Permafrost Maximum(LLPMax), the extent of permafrost of China reached 5.3×106-5.4×106 km2, or thrice that of today, but permafrost shrank to only0.80×106-0.85×106 km2, or 50% that of present, during the local Holocene Megathermal Period(LHMP), or the local Last Permafrost Minimum(LLPMin). On the basis of the dating of periglacial remains and their distributive features, the extent of permafrost in China was delineated for the two periods of LLGM(LLPMax) and LHMP(LLPMin), and the evolution of permafrost in China was divided into seven periods as follows:(1) LLGM in Late Pleistocene(ca. 20000 to 13000-10800 a BP)with extensive evidence for the presence of intensive ice-wedge expansion for outlining its LLPMax extent;(2) A period of dramatically changing climate during the early Holocene(10800 to 8500-7000 a BP) when permafrost remained relatively stable but with a general trend of shrinking areal extent;(3) The LHMP in the Mid-Holocene(8500-7000 to 4000-3000 a BP)when permafrost degraded intensively and extensively, and shrank to the LLPMin;(4) Neoglaciation during the late Holocene(4000-3000 to 1000 a BP, when permafrost again expanded;(5) Medieval Warming Period(MWP) in the late Holocene(1000-500 a BP) when permafrost was in a relative decline;(6) Little Ice Age(LIA) in the late Holocene(500-100 a BP), when permafrost relatively expanded, and;(7) Recent warming(during the 20 th century), when permafrost continuously degraded and still is degrading. The paleo-climate, geography and paleopermafrost extents and other features were reconstructed for each of these seven periods. 展开更多
关键词 PERMAFROST EVOLUTION Cryogenic wedge structures LOCAL LAST GLACIAL Maximum(LLGM) LOCAL Holocene MEGATHERMAL Period(LHMP) China
青海204省道祁默段沿线多年冻土发育特征
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作者 庞伟军 常刚 +1 位作者 苟海瑞 王瑜鑫 《冰川冻土》 CSCD 北大核心 2019年第1期93-99,共7页
采用踏勘、挖探、钻探和地温测试手段,对区间冻土的分布、上限、年平均地温、含水率及冻土地貌等特征进行了分析研究。结果表明:研究区域多年冻土主要分布在海拔3 600 m以上地区;单一地貌形态下,冻土上限和年平均地温与海拔均呈近线性... 采用踏勘、挖探、钻探和地温测试手段,对区间冻土的分布、上限、年平均地温、含水率及冻土地貌等特征进行了分析研究。结果表明:研究区域多年冻土主要分布在海拔3 600 m以上地区;单一地貌形态下,冻土上限和年平均地温与海拔均呈近线性分布关系;受地形主控,积雪、蒸发、土体结构共同影响,相同海拔位置大冬树山北坡峡谷区冻土上限和年平均地温分别深和高于南坡缓坡区;地下含水量越高越有利于冻土的发育和保存,除影响冻土类型外,其在冻土边缘带是岛状冻土形成的主要因素;冻融草丘和冻融滑塌的发育程度一定程度上反映了冻土的基本特性。最后,针对区域冻土发育特征,探讨了204省道工程建设中冻土路基处理的应对工程措施。 展开更多
关键词 地温测试 多年冻土 发育特征 工程措施
青藏铁路多年冻土区电力杆塔热桩基础的降温效果分析
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作者 周亚龙 王旭 +2 位作者 郭春香 蒋代军 胡渊 《冰川冻土》 CSCD 北大核心 2019年第1期100-108,共9页
在热棒外围浇筑混凝土形成的热桩基础在冻土区电力杆塔中常被应用。热棒的工作功率随着大气温度、蒸发段土体温度的变化而变化。基于冻土传热学相关知识,结合青藏铁路望昆~不冻泉段电力杆塔基础的现场地温测试试验,建立热桩基础的三维... 在热棒外围浇筑混凝土形成的热桩基础在冻土区电力杆塔中常被应用。热棒的工作功率随着大气温度、蒸发段土体温度的变化而变化。基于冻土传热学相关知识,结合青藏铁路望昆~不冻泉段电力杆塔基础的现场地温测试试验,建立热桩基础的三维有限元模型。考虑全球气候变暖、冻土相变、混凝土水化放热、热棒功率变化等因素,运用迭代的方法进行热棒功率和桩周土体温度计算。计算结果表明:计算结果与实测结果吻合程度较高,能较好的模拟现场情况。热棒的功率呈非连续波浪式变化,受混凝土入模温度及水化放热的影响,初始阶段功率达到最大160.6 W,第2年的平均功率比第1年低7.0 W。热桩基础能够有效增加基础冷储量,最大降低桩侧土体地温2.1~3.0℃,年平均地温降低0.8~1.5℃,能缩短桩周土体回冻时间约34%,第30 a可提高冻土上限49 cm。 展开更多
关键词 多年冻土 热桩基础 热棒功率 降温效果
Changes in freezing and thawing indices over the source region of the Yellow River from 1980 to 2014 预览
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作者 Rui Wang Qingke Zhu Hao Ma 《林业研究:英文版》 CAS CSCD 2019年第1期257-268,共12页
Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate change.However,to date,research on ground-surface freezing and thawin... Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate change.However,to date,research on ground-surface freezing and thawing indices and their relationship with air indices is limited.Based on daily air and ground-surface temperatures collected from 11 meteorological stations in the source region of the Yellow River,the freezing and thawing indices were calculated,and their spatial distribution and trends were analyzed.The air-freezing index(AFI),air-thawing index(ATI),ground surface-freezing index(GFI),ground surface-thawing index(GTI),air thawing-freezing index ratio(Na)and surface ground thawing-freezing index ratio(Ng)were 1554.64,1153.93,1.55,2484.85,850.57℃-days and 3.44,respectively.Altitude affected the spatial distribution of the freezing and thawing indices.As the altitude increased,the freezing indices gradually increased,and the thawing indices and thawing-freezing index ratio decreased.From 1980 to 2014,the AFI and GFI decreased at rates of 8.61 and 11.06℃-days a^-1,the ATI and GTI increased at 9.65 and 14.53℃-days a^-1,and Na and Ng significantly increased at 0.21 and 0.79 decade^-1.Changes in the freezing and thawing indices were associated with increases in the air and ground-surface temperatures.The rates of change of the ground surface freezing and thawing indices were faster than the air ones because the rate of increase of the groundsurface temperature was faster than that of the air and the difference between the ground surface and air increased.The change point of the time series of freezing and thawing indices occurred in 2000–2001.After 2000–2001,the AFI and GFI were lower than before the change point,and the changing trend was lower.The ATI,GTI,Na and Ng during 2001–2014 were higher,with faster rates than before.In addition,the annual thawing indices composed a greater proportion of the mean annual air temperature and mean annual ground surface temperature than the annual freezing ind 展开更多
关键词 CLIMATE change FREEZING and thawing indices PERMAFROST The source region of the YELLOW RIVER
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