Estimation of Land Subsidence Based on Groundwater Flow Model   总被引：8，自引：0，他引：8  

Shui-Long Shen  Ye-Shuang Xu  Zhen-Shun Hong 《Marine Georesources & Geotechnology》2006,24(2):149-167

This article presents an approach for estimating land subsidence due to withdrawal of groundwater. The proposed method calculates the groundwater seepage in 3-D-condition and calculates the land subsidence one-dimensionally. The governing equation on groundwater seepage is based on the three-dimensional mass conservation law and the principle of effective stress. The land subsidence calculation method is derived based on the following assumptions: (1) displacements occur only in the vertical direction, and (2) in vertical direction the total stresses do not change. The governing equation is solved by numerical method, i.e., finite element method (FEM) in spatial discretization and finite difference method (FDM) in time series discretization. In FEM Galerkin method is adopted and in FDM, lumped matrix method is employed. The proposed method is calibrated via analyzing 1-D consolidation problem and the results are compared with those from Terzaghi's one-dimensional consolidation theory and oedometer test. The proposed method is employed to analyze the consolidation of a soft layer due to withdrawal of groundwater from an aquifer under it. Moreover, this method is also applied to a field case of land subsidence due to groundwater pumping in a gas production field in Japan. The analytical results are compared with the field observed data. The results show that this approach simulates the field case well.  相似文献   

Model simulations of carbon sequestration in the northwest Pacific by patch fertilization     

Katsumi Matsumoto 《Journal of Oceanography》2006,62(6):887-902

Iron fertilization of nutrient-rich surface waters of the ocean is one possible way to help slow the rising levels of atmospheric CO₂ by sequestering it in the oceans via biological carbon export. Here, I use an ocean general circulation model to simulate a patch of nutrient depletion in the subpolar northwest Pacific under various scenarios. Model results confirm that surface fertilization is an inefficient way to sequester carbon from the atmosphere (Gnanadesikan et al., 2003), since only about 20% of the exported carbon comes initially from the atmosphere. Fertilization reduces future production and thus CO₂ uptake by utilizing nutrients that would otherwise be available later. Effectively, this can be considered as leakage when compared to a control run. This “effective” leakage and the actual leakage of sequestered CO₂ cause a significant, rapid decrease in carbon retention (only 30–45% retained after 10 years and less than 20% after 50 years). This contrasts markedly with the almost 100% retention efficiency for the same duration using the same model, when carbon is disposed directly into the northwest Pacific (Matsumoto and Mignone, 2005). As a consequence, the economic effectiveness of patch fertilization is poor in two limiting cases of the future price path of carbon. Sequestered carbon in patch fertilization is lost to the atmosphere at increasingly remote places as time passes, which would make monitoring exceedingly difficult. If all organic carbon from one-time fertilization reached the ocean bottom and remineralized there, acidification would be about −0.05 pH unit with O₂ depletion about −20 μmol kg⁻¹. These anomalies are probably too small to seriously threaten deep sea biota, but they are underestimated in the model because of its large grid size. The results from this study offer little to advocate purposeful surface fertilization as a serious means to address the anthropogenic carbon problem.  相似文献   

基于AHP法和灰色模式识别理论的海底管道系统路由定量风险评估   总被引：3，自引：1，他引：3  

徐慧 肖楠郭振邦  王金英 《海洋工程》2005,23(4):105-110

根据海底管道路由潜在风险的特点及风险类型,提出了一种将层次分析法（AHP法）和灰色模式识别理论相结合的海底管道系统路由定量风险评估方法,该方法利用AHP确定风险评价指标体系,运用灰色模式识别理论,建立识别结果标准,并结合实际工程进行计算,计算结果表明该方法是可行的.  相似文献   

种植盐地碱蓬修复滨海盐渍土效果的研究   总被引：25，自引：0，他引：25  

林学政  沈继红  刘克斋  黄晓航 《海洋科学进展》2005,23(1):65-69

利用盐生植物——盐地碱蓬进行天津河口滨海盐碱地的生物修复。通过比较种植盐地碱蓬土壤和对照土壤的电导率、有机质和微生物数量的差异等研究了其修复效果。结果表明，种植区碱蓬根际土壤的电导率与对照土壤相比下降了13％；有机质和总氮与对照土壤相比分别增加43％和18％；根际土壤的微生物数量明显增加，放线菌和真菌分别比对照增加了5倍和16倍。根际微生物优势种群的盐耐受性结果显示，部分根际土壤的优势种群的盐耐受性明显下降，耐盐性较低的微生物种群已成为优势种群。以上结果表明，种植盐地碱蓬对改善滨海盐碱地的生态有明显的效果。  相似文献   

New target-strength model indicates more krill in the Southern Ocean   总被引：5，自引：3，他引：5  

Demer  David A.; Conti  Stephane G. 《ICES Journal of Marine Science》2005,62(1):25-32

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Geographic variation of golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella) in the North Atlantic based on otolith shape analysis   总被引：1，自引：0，他引：1  

Stransky  Christoph 《ICES Journal of Marine Science》2005,62(8):1691-1698

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Carbon cycling through the pelagic foodweb in the northern Humboldt Current off Chile (23{degrees}S)     

Gonzalez  H.E.; Giesecke  R.; Vargas  C.A.; Pavez  M.; Iriarte  J.; Santibanez  P.; Castro  L.; Escribano  R.; Pages  F. 《ICES Journal of Marine Science》2004,61(4):572-584

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Diel vertical behaviour, predator-prey relationships, and occupation of space by jack mackerel (Trachurus murphyi) off Chile   总被引：3，自引：0，他引：3  

Bertrand  Arnaud; Barbieri  Maria Angela; Cordova  Jose; Hernandez  Carola; Gomez  Fabian; Leiva  Francisco 《ICES Journal of Marine Science》2004,61(7):1105-1112

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Effect of Sea Level Variation on Tidal Characteristic Values for the East China Sea     

于宜法  俞聿修  左军成  万振文  陈宗镛 《中国海洋工程》2003,17(3)

1 .IntroductionTheglobalairtemperatureroseabout 0 .5～ 0 .6°Coverthepast 2 0thcentury ,andtheglobalmeansealevelincreasedbyabout2 0cmduringtheperiod .Theregionalmeansealevelriseswiththerisingglobalmeansealevel.Zuoetal.( 1 997)indicatedthatthemeanrisingrateofabsolutemeansealevelalongtheChinacoastontheassumptionofunifiedisostaticdatumis 2mm a .Woodworth( 1 999)analyzedsealevelspanning 1 76 8tothepresentinLiverpool,andobtainedaseculartrendforheperiodupto 1 880of0 .39± 0 .1 7mm a ,andatrendfort…  相似文献   

Meiobenthic Organisms as Indicators of Mixing Processes in the Baltic Surface Sediments*     

Janusz Pempkowiak  Joanna Kozuch  Maria Szymelfenig 《Marine Ecology》1996,17(1-3):175-179

Abstract. Two sediment cores were collected in the southern Baltic Sea and sliced into 1.0cm-thick layers. Sediments of each layer were analysed for activities of ²¹⁰Pb, ¹³⁷Cs, ¹³⁴Cs and for the density of meiobenthic organisms (meiofauna). Zones with the rapid mixing occur in the uppermost layers (0–3 cm) of the cores based on ^I34Cs profiles. The extent and density of meiofauna confirmed the rapid mixing and revealed layers with slow mixing (4–8 cm). Sedimentation rates were derived from ²¹⁰Pb profiles below the mixing zones (1.21 and 1.72 mm a-^I) and were confumed by ¹³⁷Cs distribution. Of twenty-one major meiofauna taxa commonly found in the Baltic sediments, three were present in the cores.  相似文献