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801.
辽东山地老秃顶子冰缘地貌特征及其环境意义 总被引:1,自引:0,他引:1
通过对以老秃顶子为中心的辽东冰缘地貌分布区考察研究, 发现区内广泛发育的冰缘地貌类型为石河、石流坡、石海, 偶见石堡、雪蚀洼地、寒冻风化崩坍崖和倒石堆. 砾石大小不一, 堆积混杂无序, 在地表径流的作用下, 具有潜在的移动性. 风化淋溶以石流坡地貌最为显著, 土壤营养元素含量及成壤作用均以石河最优. 石下暗河发育, 上覆植被多样, 植被类型随海拔自高向低可划分为灌草丛、灌丛、矮曲林、暗针叶林、针阔混交林、落叶阔叶林, 其群落类型变化与冰缘过程趋于复杂化具有一致的发展趋势. 由于该区生境条件苛刻, 植被演替极慢且容易发生山地灾害, 建议加强人为干预, 改善植被覆盖状况, 促进演替进度, 以提高此冰缘地貌的稳定性. 相似文献
802.
东亚地区水汽输送强、弱年水汽输送的异同 总被引:5,自引:1,他引:4
利用1950-2002年NCAR/NCEP再分析逐日平均资料,计算全球格点整层水汽输送通量,分析东亚地区水汽输送强、弱年候平均水汽输送的异同点.水汽输送强、弱年都存在一条行星尺度水汽输送带,但是又有显著的差异:(1)南半球越赤道、阿拉伯海、孟加拉湾的水汽输出量不同.(2)副热带高压外围水汽的强度和影响范围不同.(3)中纬度向内蒙古中部和东北地区输送水汽的偏西风水汽输送带在水汽输送强年明显、弱年不明显.(4)在水汽输送强年中国云贵高原-长江中游-华北-东北南部有一条明显的水汽输送大值带,中国中、东部均有水汽输送,只是中国东南部和长江中下游地区水汽输送相对较少;在水汽输送弱年仅中同南方、东部沿海和东北地区南部有弱的水汽输送.(5)水汽输送强年的变化较为平缓,而水汽输送弱年则比较迅速.东哑地区偏南风水汽输送在水汽输送强、弱年的相同特征是:特征线南撤的速度非常快,在20°一30°N附近有东南风水汽输送加入,并取代西南风水汽输送;不同之处是,水汽输送强年建立的时间早、能够到达更北的纬度、强盛期长、撤退的时间迟.副热带高压南侧东南风水汽输送在水汽输送强、弱年的共同点是,西界均为95°E,由建立到强盛的速度郁非常快,在强盛期突然就东撤到130°E以东的区域;不同点是,在160°E处东南风水汽输送建证的时间不同,强盛期不同,纠达西界的时间不同,印度季风槽在95°E以西形成的东南风水汽输送持续时间和影响范围不同,西扩和东撤的速度不同. 相似文献
803.
将8个主要平衡分潮加入到耦合模式中,对比研究潮汐对北大西洋模拟影响。由于潮汐的引入,模式模拟SST在北大西洋中纬度区域偏差显著减小,高纬度区域SST降温明显。SST模拟的改变使潮汐试验的海表净热通量模拟误差下降了约30%,但高纬度海冰显著增加。模式中引入潮汐对北大西洋上层环流,尤其是西边界流的路径模拟改进显著,这是SST及海表净热通量模拟改变的主要原因。同时,北大西洋上层和深层西边界流在潮汐的作用下,都表现出环流减弱的特点,这也使得大西洋经向翻转环流在26.5°N处上层2 km的输送减弱,与观测数据更为接近。较弱的大西洋经向翻转环流导致海洋热量在中低纬度聚集而无法输送到高纬度区域,这是造成潮汐试验模拟的海温在中低纬度偏高、高纬度偏低的原因,较弱的热输送也同时导致了潮汐试验中北半球海冰面积增加。 相似文献
804.
One of the major drawbacks of the conventional method of land reclamation, which involves mixing cement with the dredged soils at the disposal site, is the high cost associated with its manufacturing and transportation. In this study, a new solidified dredged fill (SDF) technique and a new additive are proposed and their practical applications are discussed. Unlike the conventional approach, the dredged marine soils were mixed with the solidifiers using a newly designed mixing technique prior to its transport to site, which would significantly reduce the cost of site machinery and effectively reclaim land with adequate engineering properties necessary for the construction of infrastructure. To evaluate the performance of the reclaimed land using the proposed technique, a series of laboratory and field tests (namely, static and dynamic cone penetration tests, and plate load tests) were conducted on grounds filled with and without solidified dredged marine soils, respectively. The results showed that the engineering behavior of the reclaimed land with dredged marine soils using SDF technique had significantly improved. The SDF technique combined with the newly designed mixing system improved the performance of ground and has thus proved to be both cost-effective and safe. 相似文献
805.
介绍COSMIC技术反演电离层电子密度的研究现状、技术和方法,验证其可靠性;并利用COSMIC掩星数据计算分析2011-03-11东日本大地震震前5d及地震当天震区上空电离层电子密度分布,探测到显著的震前电离层异常现象,证明COSMIC技术研究地震电离层异常的可行性。 相似文献
806.
807.
808.
Using ASTER(Advanced Spaceborne Thermal Emission and Reflection Radiome-ter) infrared remote sensing data we inversed the parameters of urban surface heat fluxes applying the PCACA model and theoretical position algorithm,and then we analyzed the in-fluence of different land use types on the surface heat fluxes and energy balance.In this study,Kumagaya,a city in Saitama Prefecture,Japan,was selected as the experimental area.The result shows that the PCACA model is feasible for the surface heat fluxes estimation in urban areas because this model requires less parameters in the procedure of heat fluxes estimation in urban areas with complicated surface structure and can decrease the uncertainty.And we found that different land-use types have indicated the height heterogeneity on the surface heat fluxes significantly.The magnitudes of Bowen ratio in descending order are industrial,residential,transportation,institutional,dry farmland,green space,and water body.Under the same meteorological condition,there are distinct characteristics and regional differences in Bowen ratios among different surface covers,indicating higher sensible heat flux and lower latent heat flux in the urban construction land,while lower sensible heat flux and higher latent heat flux in the vegetation-covered area,the outskirt of the urban area.The increase of urban impervious surface area caused by the urban sprawl can enlarge the sensible heat flux and the Bowen ratio,so that it causes the increasing of urban surface temperature and air tem-perature,which is the mechanism of the so-called heat island effect. 相似文献
809.
810.
Yanbin Yao Dameng Liu Yao Che Dazhen Tang Shuheng Tang Wenhui Huang 《International Journal of Coal Geology》2009,80(2):113-123
This paper demonstrates capabilities of microfocus X-ray computed tomography (µCT) in characterizing the development of coal porosity and fractures. For the investigated coals, the CT number of minerals, pores and coal matrix are approximately 3000, < 600 and 1000–1600 Hounsfield unit (HU), respectively. The total CT number of analyzed coals mainly relate to the density, coal maceral composition, and proportion of minerals and pores. Although the estimated porosities by segmentation method show some uncertainty, the results correlate well with the analyzed porosities by helium gas method and water-saturated method. The aperture, spacing and spatial distribution of fractures, and mineral morphology are semi-quantitatively evaluated by µCT using a computer-aided design. The slicing analyses of coals demonstrated that distributions of porosity in coals are highly anisotropic. The spatial disposition of pores, fractures and minerals is the most important factor that influences coal porosity and permeability. In spite of the limitation of low spatial resolution (70 μm) and some ring artifacts of X-ray, µCT has major advantages in non-destructive detection and 3D visualized characterization of pores, fractures and minerals compared to traditional methods. 相似文献