Numerical study of circulation and temperature-salinity distributions in the Bras d’Or Lakes     

Bo Yang  Jinyu Sheng  Bruce G. Hatcher  Brian Petrie 《Ocean Dynamics》2007,57(4-5):245-268

The Bras d’Or Lakes (BdOL) are a large, complex and virtually land-locked estuary in central Cape Breton Island of Nova Scotia and one of Canada’s charismatic ecosystems, sustaining ecological and cultural communities unique in many aspects. The BdOL comprise two major basins, many deep and shallow bays, several narrow channels and straits and a large, geologically complex watershed. Predictive knowledge of the water movement within the estuary is a key requirement for effective management and sustainable development of the BdOL ecosystem. A three-dimensional (3D) primitive-equation ocean circulation model is used to examine the estuary’s response to tides, winds and buoyancy forcing associated with freshwater runoff in a series of numerical experiments validated with empirical data. The model results generate intense, jet-like tidal flows of about 1 m s^?1 in the channels between the basins and connecting them to the ocean and relatively weak tidal currents in other regions, which agrees well with previous observations and numerical results. Wind forcing and buoyancy forcing associated with river runoff play important roles in generating the significant sub-tidal circulations in the estuary, including narrow channels, deep basins and shallow bays. The circulation model is also used to reconstruct the 3D circulation and temperature-salinity distributions in the summer months of 1974, when current and hydrographic measurements were made at several locations. The sub-tidal circulation in the estuary produced by the model is characterised by wind and barometric set-up and set-down in different sections of the system, and a classic two-layer estuarine circulation in which brackish, near-surface waters flow seaward from the estuary into the Atlantic Ocean, and deep salty waters flow landward through the major channel. The model results reproduce reasonably well the overall features of observed circulation and temperature-salinity fields made in the BdOL in 1974 but generally underestimate the observed currents and density stratification. The model discrepancies reflect the use of spatially mean wind forcing and spatially and monthly mean surface heat flux and the inability of the coarse model horizontal resolution (～500 m) to resolve narrow channels and straits.  相似文献   

2008年7月13-14日河南大暴雨过程的V-3θ图特征分析   总被引：2，自引：0，他引：2  

侯凯  闫瑾瑜  靖春悦 《气象与环境科学》2011,34(2):49-53

运用天气学分析方法和V-3θ图结构分析方法,对2008年7月13-14日河南省中部、北部地区的突发性大暴雨过程进行了分析.结果表明:从常规天气学角度预报突发性暴雨难度较大,V-3θ图结构分析方法可以在一定程度上弥补天气学分析对突发性强降水预报能力的不足.在郑州、南阳及阜阳探空站的V-3θ图上,能明显看出此次暴雨过程中的...  相似文献   

济南市平阴县大孙庄地区地热氡泉形成机理探析          下载免费PDF全文

白新飞  宋津宇  张军  杨时骄  于超  翟立民  张松林 《山东国土资源》2022,38(10)

济南市平阴县玫瑰镇大孙庄已发现两眼地热氡泉井,地热流体中氡含量高达332.6～625.7Bq/L,属于稀缺的天然理疗热矿水资源。采用土壤面积测氡、土壤剖面测氡、可控源音频大地电磁法（CSAMT）测量、水氡测试等方法,研究其形成机理。通过分析氡的物源条件、空间条件、动力条件,结合地热田的地质条件、水文地质条件、构造条件、水化学特征,建立了大孙庄地热氡泉形成机理模型,为在具有类似地质背景条件的地区勘查开发地热氡泉提供借鉴。  相似文献   

Pore Characteristics and Factors Controlling Lacustrine Shales from the Upper Cretaceous Qingshankou Formation of the Songliao Basin,Northeast China: A Study Combining SEM,Low-temperature Gas Adsorption and MICP Experiments     

HAN Hui  DAI Jie  GUO Chen  ZHONG Ningning  PANG Peng  DING Zhengang  CHEN Jianping  HUANG Zhenkai  GAO Yuan  LUO Jinyu  LI Qirui  ZHANG Zhaokun 《《地质学报》英文版》2021,95(2):585-601

To investigate pore characteristics and the factors controlling lacustrine shales,geochemical,mineralogical and petrophysical experiments were performed on 23 shale samples from the Qingshankou Formation of the Songliao Basin,China.A comparison of mercury injection capillary pressure (MICP) and low-temperature N2 adsorption pore-size distribution showed that MICP has a higher pore-size distribution (PSD) line in its overlapping pore diameter range,which may be elevated by the higher pressure of MICP.Therefore,in the overlapping range,low-temperature N2 adsorption data were preferred in pore characterization.Negative correlations were observed between pore volumes and TOC content,indicating organic matter pores are not well-developed in the studied samples.This may be related to their low grade of maturity and type I kerogens.There existed negative relationships between pore volumes and S1,which illustrated that liquid hydrocarbons occupied some pore space.Micropore volume had a better correlation with S1 than mesopore and macropore volumes,which suggests that liquid hydrocarbons preferentially occur in micropores.No obvious relationships between pore volumes and quartz or feldspar were observed,while pore volumes increased with the increasing clay mineral content.These relationships indicate that intraparticle pores in clay minerals represent the principal pore type.  相似文献   

隐伏断层在强震砂土液化中的作用——以2008年汶川Mw 7.9地震为例     

王鹏  刘静  张智慧  李志刚  张金玉  王伟  邢秀臣 《地质通报》2018,37(5):747-758

2008年汶川Mw7.9地震的强地面震动在龙门山前地区造成大量的砂土液化、喷砂冒水等地震灾害现象。震后野外调查发现,砂土液化点主要分布于地下水位只有几米深的山前河流的低阶地处,以大面积砾性土液化为特征,约58%的液化点位于距北川断层20~35km的范围内。对喷水高度及喷水过程进行了详细记录,喷水高度与峰值加速度并没有明显的相关性,喷水高度异常点(2m)集中于山前断裂系统近地表投影处。汶川地震中喷水高度异常、砾性土液化的位置与山前断裂系统的吻合性说明,沉积盆地内的地质构造可能在砂土液化强度和与震动相关的地震灾害方面起到促进作用,所以在类似的地质和水文环境中,除主震的断层错动外,应考虑地质构造在地震危险性评估和建筑物抗震设计中的重要作用。  相似文献   

中国海域1:100万地质地球物理MapGIS制图     

温珍河  张训华  杨金玉  尹延鸿  邱燕  王乃东  张明 《地球信息科学学报》2011,13(6):750-757

 中国海域1:100万地质地球物理系列图包括布格重力异常图、空间重力异常图、磁力异常图、表层沉积物分布图和区域构造图5种图件.利用数字化编图技术对新旧资料进行同化处理和标准化处理,在编图的过程中,采取多种技术手段确保编图质量,并进行了GIS数据库的构建工作.地理底图和各专题图件均在MapGIS基础平台上以点、线、面三种图元类型表示,根据实际材料和图面内容进行分层设计、分层构建、统一成图的技术路线,为日后资料使用和图件修编奠定了良好基础.以MapGIS为平台,可以很好地完成地质地球物理系列编图任务.  相似文献   

深圳近海风暴潮影响因素分析     

邓国通  刘敏聪  邢久星  申锦瑜  周凯  陈胜利 《热带海洋学报》2022,41(3):91-100

风暴潮可能给沿海城市造成巨大破坏, 而深圳位于易受台风影响的南海北部沿岸, 经济和人口总量巨大, 但有关深圳近海风暴潮的研究工作却十分匮乏。本文基于区域海洋模式系统(regional ocean model system, ROMS)建立了一个以深圳近海为中心的三层嵌套模型, 用于研究深圳近海台风所致风暴潮的影响因素。首先对2018年台风“山竹”过境深圳导致的风暴潮进行模拟, 模拟结果与观测结果较为一致。在此基础上, 进行一系列参数调整试验, 研究台风登陆地点、登陆角度、台风尺度、台风强度以及移动速度的改变对风暴潮及其分布的影响。结果表明, 在深圳西边登陆的台风, 比在深圳东边登陆的台风产生的最大增水高1.5m左右。由东往西移动并登陆深圳的台风, 比由南向北移动的台风产生的最大增水高1.0m左右。台风最大风速半径增加15%, 最大增水上升0.2m左右。台风强度增强15%, 最大增水上升0.4m左右。台风移动速度总体上对风暴潮影响不大, 但不同登陆地点存在明显差异。当台风在深圳西边或者东边登陆时, 台风移动速度增加30%, 深圳沿海各海湾的最大增水反而上升0.2~0.6m。当台风从深圳中部登陆时, 台风移动速度增加30%, 珠江口的最大增水降低0.1m左右, 大鹏湾和大亚湾的最大增水却相反地上升0.2m左右, 不同海湾对台风移动速度呈现不同的变化特征, 与各海湾水体重新分布到稳定状态时间和台风作用时间有关。  相似文献   

中国房山世界地质公园地质旅游开发与可持续发展     

程素珍  张长敏  华金玉 《城市地质》2012,7(3):38-40

中国房山世界地质公园地质旅游资源丰富、种类众多。特殊的地质背景造就了这些具有重要科研和观赏价值的地质遗迹。分析了公园开发过程中存在的问题,并提出公园可持续发展对策。  相似文献   

国家地质公园规划编制原则     

程素珍  华金玉  陈铁军 《城市地质》2013,8(1):11-12

编制国家地质公园规划,是建设好地质公园的重要工作。本文讨论了国家地质公园的规划编制原则和重点内容,为有关地质公园规划提供参考。  相似文献   

A numerical study of the circulation and monthly-to-seasonal variability in the Caribbean Sea: the role of Caribbean eddies     

Yuehua Lin  Jinyu Sheng  Richard J. Greatbatch 《Ocean Dynamics》2012,62(2):193-211

This study examines the circulation and associated monthly-to-seasonal variability in the Caribbean Sea using a regional ocean circulation model. The model domain covers the region between 99.0 and 54.0°W and between 8.0 and 30.3°N, with a horizontal resolution of 1/6°. The ocean circulation model is driven by 6-hourly atmospheric reanalysis data from the National Center for Environmental Prediction and boundary forcing extracted from 5-day global ocean reanalysis data produced by Smith et al. (Mercator Newsletter 36:39–49, 2010), and integrated for 7 years. A comparison of model results with observations demonstrates that the regional ocean circulation model has skill in simulating circulation and associated variability in the study region. Analysis of the model results, as well as a companion model run that uses steady annual mean forcing, illustrates the role of Caribbean eddies for driving monthly-to-seasonal circulation variability in the model. It is found that vertically integrated transport between Nicaragua and Jamaica is influenced by the interaction between the density perturbations associated with Caribbean eddies and the Nicaraguan Ridge. The impact of Caribbean eddies squeezing through the Yucatan Channel is also discussed.  相似文献