水土保持监测系统信息平台实现方法(I)——信息平台结构设计与实现

文章以密云水库上游水土保持监测系统工程为背景,说明了监测系统信息平台的设计过程和实现方式。信息平台采用数据库技术,基于Oracle和ArcSDE构建了三层服务结构的数据库体系;采用数据库、参数库与模型库分开管理的方式,实现了海量多元数据的集成存储与管理。数据库中数据类型包括矢量、栅格、影像等空间数据及多媒体、文本、数值等非空间数据。其中重点就数据库逻辑结构、数据物理存储和数据组织管理方案,以及数据库物理结构设计等内容进行了说明,同时也说明了信息平台在实际业务中的应用。     

水土保持监测系统信息平台实现方法(II)——平台更新维护系统

在水土保持监测系统信息平台实现参数库、模型库与数据库分开管理、空间数据与非空间数据集成存储于关系型数据库中的基础上,为了避免数据更新不及时或不完备而造成数据信息过时,导致信息平台变成死库,需要信息平台更新维护系统。基于这一目标,文章集中探讨了信息平台管理维护系统的结构、功能、实现方法和关键技术。其中系统结构在信息平台服务结构基础上采用C/S模式;开发平台采用ArcGIS桌面产品,以对象COM组件技术ArcObjects为平台、MicroSoftVisualBasic为开发环境,进行二次开发。从而集后台数据库和前端数据管理、更新维护于一体而实现了水土保持监测系统信息平台,也为水土保持监测系统成功运行奠定了坚实的基础。     

Comparing the utility of microwave and thermal remote-sensing constraints in two-source energy balance modeling over an agricultural landscape

A two-source (soil + vegetation) energy balance model using microwave-derived near-surface soil moisture as a key boundary condition (TSM_SM) and another scheme using thermal-infrared (radiometric) surface temperature (TSM_TH) were applied to remote sensing data collected over a corn and soybean production region in central Iowa during the Soil Moisture Atmosphere Coupling Experiment (SMACEX)/Soil Moisture Experiment of 2002 (SMEX02). The TSM_SM was run using fields of near-surface soil moisture from microwave imagery collected by aircraft on six days during the experiment, yielding a root mean square difference (RMSD) between model estimates and tower measurements of net radiation (Rn) and soil heat flux (G) of approximately 20 W m^− 2, and 45 W m^− 2 for sensible (H) and latent heating (LE). Similar results for H and LE were obtained at landscape/regional scales when comparing model output with transect-average aircraft flux measurements. Flux predictions from the TSM_SM and TSM_TH models were compared for two days when both airborne microwave-derived soil moisture and radiometric surface temperature (T_R) data from Landsat were available. These two days represented contrasting conditions of moderate crop cover/dry soil surface and dense crop cover/moist soil surface. Surface temperature diagnosed by the TSM_SM was also compared directly to the remotely sensed T_R fields as an additional means of model validation. The TSM_SM performed well under moderate crop cover/dry soil surface conditions, but yielded larger discrepancies with observed heat fluxes and T_R under the high crop cover/moist soil surface conditions. Flux predictions from the thermal-based two-source model typically showed biases of opposite sign, suggesting that an average of the flux output from both modeling schemes may improve overall accuracy in flux predictions, in effect incorporating multiple remote-sensing constraints on canopy and soil fluxes.     

A downscaling method for distributing surface soil moisture within a microwave pixel: Application to the Monsoon '90 data

A downscaling method for the near-surface soil moisture retrieved from passive microwave sensors is applied to the PBMR data collected during the Monsoon '90 experiment. The downscaling method requires (1) the coarse resolution microwave observations, (2) the fine-scale distribution of soil temperature and (3) the fine-scale distribution of surface conditions composed of atmospheric forcing and the parameters involved in the modeling of land surface-atmosphere interactions. During the Monsoon '90 experiment, eight ground-based meteorological and flux stations were operating over the 150 km² study area simultaneously with the acquisition of the aircraft-based L-band PBMR data. The heterogeneous scene is hence composed of eight subpixels and the microwave pixel is generated by aggregating the microwave emission of all sites. The results indicate a good agreement between the downscaled and ground-based soil moisture as long as the intensity of solar radiation is sufficiently high to use the soil temperature as a tracer of the spatial variability of near-surface soil moisture.     

非饱和土水气两相不相容、不可压缩渗流有限元数值分析

讨论了非饱和土中水和气体两相不相容、不可压缩渗流的达西定律及水气两相耦合的渗流运动方程及vanGenuchten土水特征曲线 ,用Galerkin法建立了非饱和土水气两相不相容、不可压缩渗流的有限元方程 ,编制了三维有限元计算程序 ,应用计算实例验证了程序的计算能力 .     

外源接种粪便好氧堆肥的微生物相变化研究

为了探明在引入外源混合微生物的粪便好氧堆肥过程中微生物种类和数量变化特性，以粪便为主要培养基，从有关环境中采集堆肥微生物进行富集培养，再以富集培养产物为起始菌种添加到新鲜粪便中,进行模拟堆肥，定量研究了粪便好氧堆肥中细菌、放线菌、霉菌和酵母菌的数量和种类，结果表明细菌是中温阶段的主要作用菌群，对发酵升温起主要作用；放线菌是高温阶段的主要作用菌群；芽孢杆菌、链霉菌、小多孢菌和高温放线菌是堆肥过程中的优势种。     

石灰和粉煤灰稳定膨胀土路基的压实特性研究

对膨胀土进行不同掺和量的石灰和粉煤灰改性处理，研究了改性膨胀土的物理性质、压实特性、压实后的强度和胀缩性变化。指出了改性膨胀土路基填料有别于一般粘性土，用击实试验的最佳含水量作为压实控制标准是不合理的，并基于试验结果提出了改性膨胀土路基压实的含量水控制标准。     

填土密实度检测技术在土坝工程中的应用

通过对新疆麦提县前进水库除险加固工程的总结，叙述了在土坝工程中采用普氏贯入仪进行填土密实度检测的方法和经验。     

广东花岗岩类岩石风化土的工程地质特征

花岗岩类岩石分布广泛，种类繁多，由于花岗岩所在地区的地形地貌复杂，地貌类型变化大，故花岗岩地区有其特有的工程地质特性，其风化土的工程地质条件也较复杂，对花岗岩风化土的风化规律及工程地质特性的研究表明，从平面分布上大致可把广东花岗岩类风化土厚度特征与地貌形态分为3个类区，并根据风化程度和土质的不同，在垂向上自上而下分为3个带，同时通过对资料统计总结了花岗岩类风化土的物理力学性质，最后对花岗岩类风化土的工程地质条件进行分析评价。     

城区防洪工程施工中水土流失预测及对策探讨

任何项目在施工中都有可能引起水土流失，而各项目水土流失的特点都不一样，因此采取的措施也不尽相同，本文就由具体的工程项目－某城区防洪工程施工时可能引起的水土流失进行预测，并提出相应对策进行探讨。