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岩石层物理与动力学研究的进展 总被引：1，自引：4，他引：1
以当代国内外岩石层物理与动力学研究的主要成就和最新动向为背景,对该学科领域的发展方向、目标和问题进行了综合研究,突出地讨论了以下四个方面:(1)当代岩石层物理与动力学发展的主导趋势和总特点;(2)岩石层物理与动力学研究的现状和趋势;(3)中国岩石层与动力学研究在全球范围内的战略地位和在发展进程中的作用;(4)中国在岩石层物理和动力学发展中的方向,目标和问题.岩石层物理与动力学研究在地球科学发展中是十分关键的领域.21世纪将是地球科学的世纪,它必将会对人类生存,科技进步和社会经济发展作出重大贡献! 相似文献
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《中国科学:地球科学》2021,(8)
草本沼泽是沼泽湿地生态系统中分布最广的沼泽类型,具有涵养水源、调节气候、储碳固碳、提供珍稀物种栖息地等重要生态功能.草本沼泽的固碳功能在减缓气候变暖,维持区域环境稳定性等方面发挥着关键作用.植被生物量是反映湿地固碳能力的重要指标,明确沼泽湿地植被生物量可为估算沼泽湿地碳储量及固碳能力提供科学基础.文章利用全国草本沼泽植被地上生物量实地调查数据,结合中国沼泽湿地分布数据集,首次从全国尺度对中国草本沼泽植被地上生物量及其空间分布格局进行了研究.结果表明:中国草本沼泽总面积为9.7×10~4km~2,草本沼泽植被地上生物量平均密度为(227.5±23.0)g C m~(-2)(95%置信区间,下同),总地上生物量为(22.2±2.2)Tg C(1Tg=10~(12)g).中国草本沼泽植被地上生物量密度总体表现东北和青藏高原地区低、华北中部和滨海地区高的特点.在中国不同沼泽分布区,草本沼泽植被地上生物量平均密度从小到大依次为:温带湿润半湿润沼泽区((182.3±49.3)g C m~(-2))青藏高原沼泽区((243.9±26.6)g C m~(-2))温带干旱半干旱沼泽区((300.5±73.2)g C m~(-2))亚热带湿润沼泽区((348.4±59.0)g C m~(-2))滨海沼泽区((675.4±73.8)g C m~(-2)).由于草本沼泽面积的不同,不同沼泽分布区草本沼泽植被总地上生物量在温带湿润半湿润沼泽区最大((9.6±2.6)Tg C),而在滨海沼泽区最小((1.1±0.1)Tg C).中国草本沼泽植被地上生物量空间分布具有明显的非地带性特征,但在部分地区也呈现出一定的地带性规律,青藏高原草本沼泽植被地上生物量总体随海拔的升高而降低,温带湿润半湿润区和温带干旱半干旱区草本沼泽植被地上生物量随干旱程度的增加先降低后趋于平缓,温带湿润半湿润区草本沼泽植被地上生物量在年均温度越高的地区相对越大.研究结果可为精准评估沼泽湿地对气候的调节作用提供科学依据,为湿地生态系统适应性管理提供决策支持. 相似文献
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内蒙古准格尔黑岱沟6号主采煤层为一超大型煤-镓矿床,镓的主要载体为勃姆石.煤相的研究可为该镓矿床镓及其特殊载体勃姆石的富集提供成因信息.通过对该煤层煤岩学和矿物学的研究,发现准格尔黑岱沟6号主采煤层的显微组分明显富集惰质组,显微煤岩类型以微亮暗煤为主,显微组分的形态特征及其组合关系反映出该煤层的主采分层是干燥沉积条件下或潜水面高低交替变化使泥炭表面周期性干燥环境下形成的.该煤层中镓及其特殊载体勃姆石的最佳富集条件处于4个过渡带:(ⅰ)山麓沉积和下三角洲平原过渡带的上三角洲平原沉积;(ⅱ)微环境属于干燥森林沼泽和潮湿森林沼泽的过渡带,但偏向于干燥森林沼泽;(ⅲ)森林密度处于由大变小的过渡带;(ⅳ)在泥炭周期性堆积中,居于2个高位泥炭沼泽转折处的低位泥炭沼泽. 相似文献
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内蒙古准格尔黑岱沟6号主采煤层为一超大型煤-镓矿床,镓的主要载体为勃姆石.煤相的研究可为该镓矿床镓及其特殊载体勃姆石的富集提供成因信息.通过对该煤层煤岩学和矿物学的研究,发现准格尔黑岱沟6号主采煤层的显微组分明显富集惰质组,显微煤岩类型以微亮暗煤为主,显微组分的形态特征及其组合关系反映出该煤层的主采分层是干燥沉积条件下或潜水面高低交替变化使泥炭表面周期性干燥环境下形成的.该煤层中镓及其特殊载体勃姆石的最佳富集条件处于4个过渡带(i)山麓沉积和下三角洲平原过渡带的上三角洲平原沉积;(ii)微环境属于干燥森林沼泽和潮湿森林沼泽的过渡带,但偏向于干燥森林沼泽;(iii)森林密度处于由大变小的过渡带;(iv)在泥炭周期性堆积中,居于2个高位泥炭沼泽转折处的低位泥炭沼泽. 相似文献
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大陆动力学是研究和探索地球内部物质大尺度运动和深化认识地球本体与其在整体运动中深部圈层耦合、介质与结构变异的物理－力学属性、物质与能量的交换、深层动力过程和机制的一门边缘科学.地球动力学集成了当代众多高、新学科技领域和学科交叉的研究成果,它涉及到成山、成盆、成岩、成矿、成灾和深化对地球本体的认识,它在地球科学研究中占有极为重要的地位.本文通过深入研究、综合集成与剖析讨论了该领域五个重要的基本科学问题,即：(1)地球动力学在地球科学研究中的地位和作用;(2)国际上地球动力学研究的进展和发展动向;(3)中国地球动力学的研究状况;(4)当今地球动力学研究的导向和战略思考;(5)地球动力学研究在我国的实现和开拓. 相似文献
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《地震研究》2021,44(2)
基于韧性城市建设的内涵与目标,综合多种灾害类型,构建了城市综合防灾减灾规划内容体系。以宁波市综合防灾减灾规划为例,从4个方面提出了综合防灾减灾规划建议:(1)基于灾害综合风险,通过布设灾害防御基础设施和提升灾害监测预警能力,加强台风、地质灾害等重点危险区域防御能力,构建韧性城市防御体系;(2)结合风险空间分布与城市长远发展规划,优化整体安全布局,构建基于安全分区的韧性城乡空间规划;(3)构建多灾兼顾的应急保障设施及海空陆铁一体化的应急救援体系,实施分区性部署,强化城市应急保障设施建设;(4)强化智能化灾害风险监测预警能力建设,构建强韧性应急指挥与队伍管理体系。 相似文献
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《国际地震动态》2019,(11)
通过梳理安徽省内2014—2017年观测系统、人为干扰等6类数据异常事件,形成背景值数据库,借此深入剖析事件的变化特征,综合研究得出:(1)时间变化显示,安徽省内各类异常事件条目大体呈逐年增多的趋势;(2)学科特征显示,地电、地磁、形变、流体观测异常事件均以某类事件为主,具有一定的学科特征;(3)空间分布显示,各类异常事件呈随机性分布,不具有明显的区域特征;(4)各类事件均形成以影响因素、变化形态为主要指标的特征库,已作为安徽省内跟踪分析工作的重要判定依据。这些研究成果不仅为安徽地区的前兆异常判定和趋势预测提供一定的科学依据,也为安徽前兆仪器运维工作提供了方法指导。 相似文献
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本文概述了地震预报专家系统(Expert System for Earthquake Prediction).ESEP 包括3个子系统:中长期预报系统、年度预报系统和中短期预报系统.每一子系统均由7个模块组成:控制模块、数据库、专家知识库、方法库、事实准备模块、推理和决策模块、绘图显示模块.ESEP 中建立了推理模型 ESEP/R 和知识表示模型 ESEP/K,并提出了限制(CON)、加权(W)和综合(SYN)等3种新的证据组合方式.ESEP 的特点有:(1)体系化;(2)能综合多种专家知识;(3)拥有大量数据和专家经验;(4)采用4种推理模型并作综合决策;(5)采用多种软件环境;(6)模块化;(7)具有友好的用户界面. 相似文献
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全新世以来洞庭湖的演变 总被引：25，自引：1，他引：24
本文根据全新世沉积物的岩性、岩相特征和文化遗址的时空分布,结合孢粉资料与历史文献记载,揭示了全新世以来洞庭湖演变的六个阶段:(1)晚更新世末至全新世初为河湖切割平原;(2)中全新世早、中期(8000—5000a B.P.)是湖泊扩展时期;(3)中全新世晚期(5000—3000 a B.P.)四水复合三角洲发育,湖沼洼地零星分布;(4)商周至秦汉(3000—1700 a B.P.)四水分流间洼地湖泊和沼泽广布,汛期河湖水体相连;(5)魏晋至19世纪中叶,洞庭湖逐渐发展至鼎盛阶段;(6)19世纪中叶至今,三角洲迅速推进,湖泊逐渐萎缩。研究认为这种发育演化过程与区域性气候变化、人类活动直接相关。 相似文献
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Dissolved organic matter dynamics during the spring snowmelt at a boreal river valley mire complex in Northwest Russia 
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下载免费PDF全文 Armine Avagyan Benjamin R. K. Runkle Nina Hennings Hannes Haupt Tarmo Virtanen Lars Kutzbach 《水文研究》2016,30(11):1727-1741
Boreal mire landscapes are rich in soil carbon and significantly contribute to the carbon input of aquatic ecosystems. They are composed of different mesoscale ecohydrological subunits, whose individual contributions to the water and carbon export of mire catchments are not well understood. The spring snowmelt period is the major hydrological event in the annual water cycle of the boreal regions and strongly influences the carbon flux between the terrestrial and aquatic systems. The aim of this study was (1) to provide a conceptual understanding of the spatial and temporal dynamics of the surface water chemistry along a swamp forest‐fen‐bog gradient during the snowmelt period, (2) to quantify the exported dissolved organic carbon (DOC) content in the runoff and (3) to identify the ecohydrological landscape unit that contributes most to DOC export during the snowmelt period in a heterogeneous mire complex in Northwest Russia. The highest DOC concentrations were detected in the swamp forest, and the lowest concentrations were observed at the treeless bog by the end of the snowmelt period (swamp forest: 37–43 mg l?1, bog: 13–17 mg l?1). During the spring snowmelt period, a significant amount (~1.7 g C m?2) of DOC was transferred by the ~74 mm of runoff from the catchment into the river. Variability in the thawing periods led to differences in the relative contributions of each ecohydrological zone to the carbon export measured at a stream channel draining the studied part of the mire complex. An increased understanding of the variation in DOC concentrations and contributions from the mesoscale ecohydrological subunits to carbon export can help to predict the potential regional loss of DOC based on land cover type under climate change. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Palsa mires are mire complexes that occur in the Northern Hemisphere, representing one of the most marginal permafrost features at the outer limit of the permafrost zone. A climate‐based spatial model is presented for the distribution of palsa mires in northern Europe. The model is based on an extensive spatial data of palsa mires and climatological variables from 1913 grid cells in an area of c. 240 000 km2. Generalized linear modelling (GLM) with curvilinear and interaction terms is used to derive the palsa mire–climate relationships. The ?nal model correctly classi?ed 77·6 per cent of the palsa mire presence squares. The results indicate a positive association of the distribution of palsa mires with increasing frost number and continentality, whereas precipitation and temperature showed a negative correlation with the distribution of palsa mires. Additionally, interaction of thawing degree days and summer time precipitation showed a negative association. Climatologically, the optimum areas of palsa mires occur in areas of low precipitation (<450 mm) and a mean annual temperature between ?3 °C and ?5 °C. Potential reasons for the performance of the model and the sensitivity of palsa mires to climate change are discussed. The application of a GIS‐based generalized linear modelling as used here provides a versatile method to study the distribution of different geomorphological phenomena across climatological gradients. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Spring water table depth mediates within-site variation of soil temperature in groundwater-fed mires
Michal Horsák Veronika Horsáková Marek Polášek Radovan Coufal Petra Hájková Michal Hájek 《水文研究》2021,35(7):e14293
Groundwater-dependent ecosystems represent globally rare edaphic islands of scattered distribution, often forming areas of regionally unique environmental conditions. A stable groundwater supply is a key parameter defining their ecological specificity, promoting also soil thermal buffering. Still, a limited number of studies dealt with the importance of water temperature in mire ecosystems and virtually no data exist on within-site variation in the temperature buffer effect. Three temperature dataloggers, placed in patches potentially differing in groundwater supply, were installed in each of 19 Western Carpathian spring mire sites from May 2019 to July 2020. Spring source plots statistically differed in water temperature parameters from the plots located towards the spring mire margin, which did not significantly differ from one another. At the majority of sites, the temperature values changed gradually from spring source to mire margins, fitting the pattern expected in the groundwater temperature buffering scenario. Dataloggers placed in the spring sources were the most distinctive from the others in thermal buffering parameters in conditional principal component analysis. The difference between the spring source and its margin was on average 3.25 °C for 95th percentile of the recorded water temperature data points (i.e. warm extremes) and 1.91 °C for 5th percentile (i.e. cold extremes). This suggests that if the temperature at spring source area is considered, thermal buffering within a site may mitigate mainly warm extremes. Thus, our data may provide an important baseline for predictions of possibly upcoming changes in spring mire hydrology caused by climate change. Both warming and precipitation decrease can give rise to the loss or substantial reduction of buffering effect if the contrasting parameters now recorded at the central part shift to those found towards the margins of groundwater-fed areas. 相似文献
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This paper presents the first high resolution temperature data from a small Agrostis magellanica mire on subantarctic Marion Island as part of an ongoing island‐wide monitoring project on subsurface ground temperature variability. Variations in ground temperatures were found to be directly linked to the passage of synoptic scale weather systems that influence thermal characteristics and heat fluxes especially in the upper 30 cm of the mire. Preliminary data published here suggest that shallow temperatures will be most affected by changes in synoptic climate that Marion Island is currently experiencing with an increase in average temperatures and a reduction in temperature variability with depth. This study proposes that to effectively detect the ecosystem responses to climate change in a maritime sub‐Antarctic environment the temporal scale of measurement needs to be at least on a diurnal scale to be effective. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Large numbers of peatlands were developed in volcanic landform regions, which would provide valuable long-term records of lake–mire ecosystem shifts and act as significant carbon pool in regional carbon cycle. To investigate lake–mire ecosystem transformations and driving mechanisms in volcanic landform regions, the developmental history of Gushantun peatland in northeast China was reconstructed in this study. Results indicate that Gushantun peatland initiated in the deepest portions of the basin, and subsequently experienced expansions outward. Peat initiated from approximately 12 ka cal. bp to present. The developmental patterns of Gushantun peatland can be divided into four stages: the stable stage 1 (12–10 ka cal. bp ), maximum stage (10–7 ka cal. bp ), stable stage 2 (7–4 ka cal. bp ) and stable stage 3 (4–0 ka cal. bp ). The possible forcing mechanisms for the development of Gushantun peatland were different during different periods. From 12 ka cal. bp to 10 ka cal. bp , autogenic process was probably the major controlling factor for the expansion of this peatland. From 10 to 7 ka cal. bp , flat basin morphology was the major influence factor for fast expansion. However, the development of Gushantun peatland was probably controlled by the dual effects of high moisture and autogenic process during the period of 7 to 4 ka cal. bp . From 4 ka cal. bp to present, steep basin morphology was the major influence factor, while moisture might be the secondary factor for development of Gushantun peatland. These features indicate that lake–mire ecosystem transforms in volcanic landform regions of Changbai Mountains were probably triggered by the complex effects of autogenic process, hydroclimate and underlying basin morphology. © 2020 John Wiley & Sons, Ltd. 相似文献
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A water budget was established for the open, undisturbed bog Stormossen, central Sweden, for the growing seasons of 1996 and 1997 as a part of the NOPEX project. The water budget was complemented with data on the spatial variation of groundwater levels and water contents in different microrelief elements (ridge, hollow and ridge margin). The seasonal (24 May to 4 October) rainfall, evaporation and runoff were 200, 256, and 43 mm in 1996, respectively, and 310, 286 and 74 mm in 1997, giving negative budgets of ?99 mm in 1996 and ?50 mm in 1997. Approximately 60% of the total budget was caused by storage changes in the upper 40 cm of the bog and 40% by swelling/shrinking in the layers below. This ‘mire breathing’ must be incorporated in future models of mire‐water dynamics. The water content varied diversely among the different microrelief elements, much depending on the properties of moss and peat together with distance to water table. There also was a strong hysteresis in the relationships between groundwater level and measured volumetric water content, depending partly on pore‐throat effects and partly on swelling/shrinking of the peat matrix. A seasonal variation of volumetric water content in a layer beneath water table was found to be larger than what could be justified by compression alone. We think that probable causes could be methane gas expansion together with temperature effects. The main conclusions of this study were: (i) water‐transport and storage characteristics are distinctly different among hummocks, ridges and hollows, (ii) mire wetness cannot be deduced from groundwater levels only, and (iii) an important part of the total water storage was caused by swelling/shrinking of the peat, not by changes in unsaturated water content. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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地表糙度是衡量地表径流形成的一个重要指标．以东北区典型泥炭沼泽——金川泥炭沼泽为例,考虑地表坡度影响,用链条法对不同群落中糙度系数指标进行计算,并以泥炭沼泽中物种多样性、踏头个数以及踏头形态差异变率系数为主,初步分析泥炭泥泽地表糙度的变化机制,结果表明：在芦苇-臌囊苔草群落、臌囊苔草群落和油桦-臌囊苔草-泥炭藓群落三个植物群落中,糙度系数指标的变化与群落中物种丰富度和生物多样性变化相一致;糙度系数变化与踏头个数呈负相关关系,与踏头形态差异变率系数呈正相关关系说明物种多样性越小,生态优势度越大,优势种植物越少,踏头个数越多,踏头形态变率系数越小,微地貌形态发育相对较一致,糙度系数越小;反之,则地表糙度系数越大。 相似文献
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The hydraulic conductivity (K) of many low permeability materials is strongly scale‐dependent. In raised mires and other types of peat deposit the effects of features such as abandoned infilled ditches, root holes and localized woody material, cause K to be heterogeneous and scale‐dependent. Despite this, field measurements are routinely made using auger hole (slug) tests at the scale of only a few tens of centimetres. Such measurements are locally valid, but where the regional subsurface movement of water through peat bogs is simulated using groundwater models, typically at the scale of hundreds of metres, they give rise to a systematic underestimate of flows and an overprediction of water table elevations. Until now, techniques to obtain values at a scale sufficiently large to include the effects of localized features of higher permeability have not been applied routinely. Research at Thorne Moor, a large raised mire, demonstrates that the K of peat varies over several orders of magnitude when measured at different scales, using a variety of techniques. Laboratory and auger hole tests cannot be relied upon to provide results that represent the hydraulic conductivity of large expanses of peatland. This has significant implications for the management and long‐term restoration of peatlands where both regional and local control of water levels is crucial. For groundwater models to be used successfully to plan such schemes, it is essential to apply the K values relevant to the scale of the simulation. This paper describes and tests novel techniques, using ditches, for the derivation of K at large scales which overcome many of the problems that have been identified with conventional techniques and are capable of producing estimates that are appropriate to the application of physically based regional flow models. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Abstract Long term research has been conducted into the hydrological effects of different land usage of a wetland mire in southern Germany. Drainage for agriculture lowered the water table and reduced evaporation from about 110% of open water losses to just under the Penman short grass potential rate. The runoff regime was altered and peak flows increased. Afforestation of agricultural land increased evaporation losses to much higher levels than open water evaporation, and annual runoff was nearly halved. Forest growth reduced soil water and baseflows. Peak flows became smaller; the rate of reduction was particularly rapid in the early years of tree growth. 相似文献
20.
One of the basic limitations to the use of geomorphological maps is their coarse resolution relative to the needs of pure and applied geomorphological research. In response to this, attempts have been made to ‘downscale’ geomorphological information to finer spatial resolutions. However, the potential of statistical downscaling in geomorphology has been insufficiently examined. We downscaled four different periglacial features (wind deflation, palsa mire, earth hummock and sorted solifluction sheet) from a 100 ha grid to a 1 ha grid resolution utilizing two different techniques: point sampling (PSA) and direct (DA) approaches. We assessed the predictive accuracy of the models with the area under the curve (AUC) of a receiver operating characteristic plot using independent evaluation data. The PSA technique yielded encouraging results with a mean accuracy of 0·81, whereas the performance of DA was poorer. The predictive performance of the palsa mire and solifluction sheet models was excellent (AUC values from 0·89 to 0·96), whereas the AUC values of deflation and earth hummock models were lower (AUC = 0·57–0·81). The application of a point sampling approach as used here provides an efficient method to translate geomorphological information to finer resolution. However, further testing of the downscaling approaches is required before they can be applied to real‐world situations. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献