Two-dimensional numerical assessment of the hydrodynamics of the Nile swamps in southern Sudan

Abstract

A two-dimensional (2D) hydrodynamic assessment of the Nile swamps in southern Sudan has been carried out using DHI MIKE 21 software based on a ground referenced and corrected Shuttle Radar Topography Mission (SRTM) digital elevation model. The model was set up and calibrated using available historical information as well as newly measured data. The results show the model capable of representing the hydraulic conditions in the swamps, allowing the assessment of different flow conditions and their effects on the swamp. The study has established water-level gradients, flow directions and velocities in the swamp, as well as on the seasonal flood plains, and describes the importance of evapotranspiration for losses in the system.

Citation Petersen, G. & Fohrer, N. (2010) Two-dimensional numerical assessment of the hydrodynamics of the Nile swamps in southern Sudan. Hydrol. Sci. J. 55(1), 17–26.     

Integrating lysimeter drainage and eddy covariance flux measurements in a groundwater recharge model

Abstract

Field-scale water balance is difficult to characterize because controls exerted by soils and vegetation are mostly inferred from local-scale measurements with relatively small support volumes. Eddy covariance flux and lysimeters have been used to infer and evaluate field-scale water balances because they have larger footprint areas than local soil moisture measurements. This study quantifies heterogeneity of soil deep drainage (D) in four 12.5-m² repacked lysimeters, compares evapotranspiration from eddy covariance (ET_EC) and mass balance residuals of lysimeters (ETwb_Lys), and models D to estimate groundwater recharge. Variation in measured D was attributed to redirection of snowmelt infiltration and differences in lysimeter hydraulic properties caused by surface soil treatment. During the growing seasons of 2010, 2011 and 2012, ETwb_Lys (278, 289 and 269 mm, respectively) was in good agreement with ET_EC (298, 301 and 335 mm). Annual recharge estimated from modelled D was 486, 624 and 613 mm for three calendar years 2010, 2011 and 2012, respectively. In summary, lysimeter D and ET_EC can be integrated to estimate and model groundwater recharge.

Editor D. Koutsoyiannis     

AVO analysis with partial stacking to detect gas anomalies in the GÜEPAJÉ-3D project

We applied analysis AVO with partial stacking to an onshore gas field in order to detect gas at the top of the Ciénaga de Oro formation (FCO), by using seismic gathers of the Güepajé-3D project. The technique was supported by petrophysical analysis of the Ayombe-1 well.The sensitivity of seismic response to changes in the saturating fluid was evaluated by fluid substitution technique in an interval of the Ayombe-1 well. As a result, a class I AVO anomaly at the top of the FCO was observed, even though the gas and water responses were similar. After applying AVO with partial stack technique at the top of FCO, AVO class I anomalies were observed in the Ayombe-1 and Güepajé-1 gas wells and none in the dry Güepajé-3 well. In spite of being reported with gas, the results in the Güepajé-2 well indicated any to an incipient class I anomaly related to a weak seismic response associated to gas.When the technique was applied to the seismic volume of the Güepajé-3D Project, a map of the direct gas indicator was obtained. The map shows a high correlation with the structural surface at top of FCO. Lithic factors such as compaction, cementation and carbonate overlaying the FCO and variable thickness of partial and full saturated layers, may cause anomalies in zones unlikely to contain gas.     

三维测绘成果质量检查与评定方法研究

在分析研究现有三维模型质量标准的基础上,结合当前三维数字城市建设的实践,提出了从照片到模型两方面进行三维测绘成果质量检查与评定的方法。通过对数字南通的三维成果进行质检验证,证明该方法能够有效、全面地反映出三维测绘成果的质量。     

物联网与三维GIS技术在油田设备设施管理中的应用

针对物联网技术和三维GIS技术的特点,阐述了物联网与三维GIS之间的关系。利用油田网络、物联设备之间的传感与自动信息采集,结合三维虚拟场景提供设备设施的空间感、方位感等,使设备设施更具有时空分辨能力,为油田设备精细化管理提供条件。     

油田地面工程地理信息系统的设计与开发

根据油田地面集输数据的分布特点,采用SuperMap空间数据处理技术和二三维一体化技术,并紧密结合数字油田和物联网理念,探索与研究基于数据层、服务层和应用层的Browse/Servre模式油田地面工程地理信息系统,旨在为油田集输管理提供基础依据,提高油田事故预警、投资决策的科学性。     

3维地籍数据库变更测量方法研究

为了进一步查清城市土地的权属、位置、面积、用途等基本情况,掌握真实的土地基础数据,建立和完善城市土地调查、土地统计和土地登记制度,实现土地资源信息的社会化服务,为建立科学的城市国土资源管理与评价体系提供详实的基础数据,需要开展3维地籍数据库更新与维护,以保证地籍数据库的真实性、现势性,满足城市国土资源管理工作和经济社会发展的需要。     

基于3维的基础测绘成果客户选图服务系统研究

探讨了GeoGlobe3维GIS技术在基础测绘成果客户选图服务中的应用,主要包括系统框架设计和具体功能。     

3维激光扫描技术在石窟保护中的应用研究

高精度3维激光扫描技术的出现,为建立一套覆盖完整、细节清晰、视觉效果突出、数据真实准确的数字石窟提供了可能。云冈石窟3维数字化工作就是将3维激光扫描技术应用到石窟的制作,利用激光测距原理,以最精细、最合理的技术手段记录石窟的密集点的3维坐标、反射率和纹理等信息,完整保留全面、准确、细致的3维数据,进而复建出石窟的3维模型及线、面、体等各种数据,将云冈石窟清晰地展现出来。     

数字马鞍山3维可视化平台的设计与实现

3维可视化平台是数字城市地理空间框架的重要组成部分,本文介绍了数字马鞍山建设中3维平台的设计与实现思路。从2,3维协同服务的角度设计了3维建设技术路线,并对海量数据传输加载及2,3维联动等关键问题提出了有益的解决方案。为其他城市建设地理空间框架提供借鉴。