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941.
An urban canopy model is incorporated into the Nanjing University Regional Boundary Layer Model. Temperature simulated by the urban canopy model is in better agreement with the observation, especially in the night time, than that simulated by the traditional slab model. The coupled model is used to study the effects of building morphology on urban boundary layer and meteorological environment by changing urban area, building height, and building density. It is found that when the urban area is expanded, the urban boundary layer heat flux, thermal turbu- lence, and the turbulent momentum flux and kinetic energy all increase or enhance, causing the surface air temperature to rise up. The stability of urban atmospheric stratiˉcation is a?ected to diffierent extent at diffierent times of the day. When the building height goes up, the aerodynamic roughness height, zero plane displacement height of urban area, and ratio of building height to street width all increase. Therefore, the increase in building height results in the decrease of the surface heat flux, urban surface temperature, mean wind speed, and turbulent kinetic energy in daytime. While at night, as more heat storage is released by higher buildings,thermal turbulence is more active and surface heat flux increases, leading to a higher urban temperature. As the building density increases, the aerodynamic roughness height of urban area decreases, and the effect of urban canopy on radiation strengthens. The increase of building density results in the decrease in urban surface heat flux, momentum flux, and air temperature, the increase in mean wind speed, and the weakening of turbulence in the daytime. While at night, the urban temperature increases due to the release of more heat storage.  相似文献   
942.
A great deal of ocean sensor observation data exists, for a wide range of marine disciplines, derived from in situ and remote observing platforms, in real-time, near-real-time and delayed mode. Ocean monitoring is routinely completed using sensors and instruments. Standardization is the key requirement for exchanging information about ocean sensors and sensor data and for comparing and combining information from different sensor networks. One or more sensors are often physically integrated into a single ocean ‘instrument' device, which often brings in many challenges related to diverse sensor data formats, parameters units, different spatiotemporal resolution, application domains, data quality and sensors protocols. To face these challenges requires the standardization efforts aiming at facilitating the so-called Sensor Web, which making it easy to provide public access to sensor data and metadata information. In this paper, a Marine Sensor Web, based on SOA and EDA and integrating the MBARI's PUCK protocol, IEEE 1451 and OGC SWE 2.0, is illustrated with a five-layer architecture. The Web Service layer and Event Process layer are illustrated in detail with an actual example. The demo study has demonstrated that a standard-based system can be built to access sensors and marine instruments distributed globally using common Web browsers for monitoring the environment and oceanic conditions besides marine sensor data on the Web, this framework of Marine Sensor Web can also play an important role in many other domains' information integration.  相似文献   
943.
Sediment samples obtained from the South Mid-Atlantic Ridge were studies by gas chromatography-mass spectrometer(GC-MS) for the abundance and distributions of total fatty acids(TFAs). Approximately 34 fatty acids were identified, with the chain-lengths ranging from C12 to C30. The total concentrations of TFAs(∑TFA) ranged from 7.15 to 30.09 μg g-1 dry sediment, and ∑TFA was weakly correlated with bitumen content(R2 = 0.69). The ∑TFA of samples around hydrothermal areas were significantly higher than that of samples away from hydrothermal areas, indicating intense primary production and large biomass in the hydrothermal areas, and suggesting a close relationship between hydrothermal activity and ∑TFA of samples. The characteristics of the TFA composition in the present study are rich in monounsaturated fatty acids and lacking in polyunsaturated fatty acids, and the ratios between the concentrations of monounsaturated fatty acids and ΣTFAs in samples close to the hydrothermal areas, are about 0.8, but for samples far from the hydrothermal areas, they are only about 0.5. Several fatty acids(e.g., a/i C15:0 and C16:1ω7), which are signature biomarkers for sulfur-metabolizing bacteria, show the same distribution trend as ∑TFA of samples, further highlighting the close relationship between fatty acid content and hydrothermal activity and/or hydrothermal communities. The metabolic activities of hydrothermal communities, especially those of microorganisms, are likely the main source of fatty acids in samples.  相似文献   
944.
实景三维模型越来越多地应用于城市综合管理服务信息化中.哈尔滨市于2019年完成建城区倾斜摄影实景三维模型采集制作,本文总结了实景三维模型成果在智慧物联、智慧社区、规划实施监督等方面展开城市综合管理相关应用取得的成果,进而指出应用中存在的不足与改进展望.  相似文献   
945.
The interannual variability of global temperature and precipitation during the last millennium is analyzed using the results of ten coupled climate models participating in the Paleoclimate Modelling Intercomparison Project Phase 3. It is found that large temperature(precipitation) variability is most dominant at high latitudes(tropical monsoon regions), and the seasonal magnitudes are greater than the annual mean. Significant multi-decadal-scale changes exist throughout the whole period for the zonal mean of both temperature and precipitation variability, while their long-term trends are indistinctive. The volcanic forcings correlate well with the temperature variability at midlatitudes, indicating possible leading drivers for the interannual time scale climate change.  相似文献   
946.
给出的卫星激光测距的二轴系统实现了通过软件控制望远镜coude光路调整、接收系统SPAD和APD的自动切换、视场光阑大小的自动调节、以及发射光束指向的精确控制。该系统是基于MPC07运动控制卡,通过人机交互界面进行实时控制,旨在实现不同功能的调节,提高卫星激光测距的自动化程度。详细介绍了该系统的硬件组成、技术指标及软件工作方式。  相似文献   
947.
The Huayuan Pb-Zn ore district in China, located in western Hunan Province, is a giant carbonate-hosted Pb-Zn ore district. The source of ore-forming brines in this ore district remains poorly constrained. Whether the highly saline brines are derived from evaporated seawater or dissolved evaporates continues to be intensely debated. Carbonate minerals associated with Pb-Zn mineralization have δ13CV-PDB and δ18OV-SMOW values ranging from ?5.55‰ to +1.35‰ (mean value of ?0.69‰; n = 14) and +16.28‰ to +25.05‰ (mean value of +20.22‰; n = 14), respectively. This indicates that carbonate minerals are dominantly formed from dissolved ore-hosted carbonate rocks. The δ34S values of sulfides range from +20.2‰ to +36.8‰, with an average value of +30.0‰ (n = 27). These results suggest that sulfur is predominantly derived from the thermochemical sulfate reduction of marine sulfate. The crush-leach analyzed solute data of fluid inclusions in sphalerite show the ore-forming fluids have Cl/Br molar ratios range from 118 to 384, and Na/Br molar ratios from 39 to 160 (n = 8). These Cl/Br ratios of hydrothermal fluid are much lower than those of seawater (657 to 564), but are consistent with bittern brines through early halite precipitation. We propose that ore-forming fluids are mainly derived from evaporitic basin brines, which leached base metals from the basement and/or country rocks. The brine then migrated to the basin margins through clastic rocks of basement and then precipitated sul?des by thermochemical sulfate reduction.  相似文献   
948.
利用多波段联合观测数据,综合分析研究了一个发生于2007年5月23日的日冕物质抛射(Coronal Mass Ejection,CME)爆发事件的起源和初始阶段的物理演化过程.该CME起源于活动区10956内的一个并没有严格地位于活动区极性反转线上的U形活动区暗条,该暗条首先被扰动,然后从中间部分开始缓慢上升.在暗条上升运动过程中,从极紫外和软X射线像上可观测到位于暗条上方的日冕磁环也在不断地上升并且有持续向外的扩张运动.最终,这些冕环和暗条一起爆发并伴随着一个位于暗条断开位置附近的日冕暗化区域的形成.这一爆发过程还伴随着一个静止轨道业务卫星(GeostationaryOperational Environmental Satellites,GOES)软X射线流量级别为B5.3的亚耀斑发生,该光斑显示出与CME之间具有在时间和空间上的紧密联系.与CME的"标准"磁流绳模型一致,这些太阳表面活动可以看作是CME的初始演化阶段在日面上的表现信号,并且该CME的亮前锋可能是由预先存在于暗条上方的冕环体系直接演化而来.另外,文中还讨论了与该事件相关的暗条爆发、耀斑、冕环扩张和消失以及日冕暗化之间的关系.  相似文献   
949.
李亮  陈余道  蒋亚萍 《地下水》2010,32(3):9-11
应用矩分析方法定量分析示踪剂数据需要一系列严格的步骤,包括数据标准化,浓度衰减的校正,去卷积,外推和积分。正确的分析,可以得出示踪剂扫描孔隙体积、流体几何和流体速度等场地的特殊信息,有助于了解库区边界的特征。通过实例分析,结果表明:采用时间矩方法确定地下水有关参数时,效果良好。  相似文献   
950.
抽水作用下先期断裂对地裂缝的影响研究   总被引:1,自引:0,他引:1  
过度抽取地下水和先期存在的断裂构造是西安市地裂缝地质灾害发生的主要原因。作者首先从理论上分析了抽水情况下地裂缝形成的张拉破裂机制、剪切破裂机制和张剪复合破裂机制,并从结构面控制理论分析了先期断裂在地裂缝形成中的控制作用;然后依据比奥三维固结理论,采用FLAC软件建立了西安地裂缝的计算模型,比较了抽水作用时没有先期断裂和地层差异、有先期断裂而没有地层差异、有地层差异而无先期断裂等情况时的地面变形特征,得出抽水作用下,先期断裂对地裂缝的形成及发展具有诱导、隔离和放大的耦合作用,从而得出先期断裂不仅仅只是地裂缝形成的构造基础的结论。  相似文献   
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