台风异常运动及其外区热力不稳定非对称结构的影响效应   总被引：35，自引：9，他引：35       下载免费PDF全文

陈联寿  徐祥德  解以扬  李文弘 《大气科学》1997,21(1):83-90

本文数值模拟研究揭示了台风外区热力不稳定非对称结构对其异常路径的影响问题，提出了台风运动非对称结构的影响，不仅表现在台风涡旋动力结构特征上，而且反映在台风外区三维非对称热力结构特点方面，即包括温、湿不稳定层结分布特征及其强弱程度因素。台风外区不同热力非对称分布特征将导致台风移动轨迹的显著差异，且构成各类“旋转”、“打转”、“转向”等复杂异常路径。  相似文献   

Contribution of the North Atlantic subtropical high to regional climate model (RCM) skill in simulating southeastern United States summer precipitation     

Laifang Li  Wenhong Li  Jiming Jin 《Climate Dynamics》2015,45(1-2):477-491

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福建省海洋工程装备产业现状与发展对策探讨          下载免费PDF全文

张哲  郑国富  丁兰  蔡文鸿  魏盛军  陈思源 《海洋开发与管理》2018,35(5):114-118

近年来,福建海洋工程装备产业进步显著,初步形成了以港口装卸、海上起重机、海底铺管、大型汽车滚装船等传统装备为主导的制造基地;同时,海水淡化核心装备、海洋防腐材料、水下作业机器人、游艇装备等新兴产业也取得了快速发展,但仍存在产业基础薄弱、整体产品低端、研发力量小且分散、试验研发平台严重不足等制约"瓶颈"。文章通过现场调研和资料查询分析了福建海洋工程装备产业的发展现状,总结归纳出当前制约产业发展的主要因素,明确发展思路,提出建设具有海西特色的海工装备制造业应发展海洋工程装备的重点领域、编制福建省海洋工程装备中长期发展规划和实施方案、提升海洋工程装备科技创新能力、制定海洋工程装备发展的扶持政策、构建比较完整的重点领域海洋工程装备产业链等对策与建议。  相似文献   

云南地区房屋建筑的震害矩阵     

周光全  谭文红  施伟华  非明伦  解丽 《中国地震》2007,23(2):115-123

自1992年4月23日云南孟连西中缅交界6.7、6.9级地震始,地震部门对云南地区的破坏性地震进行了现场灾害调查和经济损失评估。1992~2003年,云南地区共发生50次破坏性地震,积累了丰富的震害资料。本文根据云南地区的主要建筑结构,统计分析了50次地震不同烈度区的破坏比、损失比和震害指数,给出了房屋建筑的震害矩阵。  相似文献   

Local kinetic energy budget of high-frequency and intermediate-frequency eddies: winter climatology and interannual variability     

Tianyu Jiang  Yi Deng  Wenhong Li 《Climate Dynamics》2013,41(3-4):961-976

The local budget of eddy kinetic energy (EKE) for both high-frequency (HF, 2–6 days) and intermediate-frequency (IF, 7–29 days) eddies are evaluated for Northern Hemisphere boreal winter using the 31-year (1979/80–2010/11) NCEP-DOE reanalysis. A new form of EKE equation is used to isolate the kinetic energy generation/destruction due to interactions among eddies of different timescales. The main source of HF EKE is baroclinic conversion that is concentrated in the mid-lower troposphere. Barotropic conversion mainly damps HF EKE and shows positive contributions to IF EKE on the northern flank of the winter-mean tropospheric jet. Interaction between HF and IF eddies acts as a sink for HF EKE and a main source for IF EKE, especially over the eastern ocean basins, confirming the substantial role of synoptic-scale transients in the development of IF phenomena such as atmospheric blocking. Large interannual variability is found for various EKE budget terms. The HF EKE response to El Niño is characterized by a dipole (tri-pole) anomaly over the North Pacific (North Atlantic). Baroclinic conversion is the main driver of the observed changes in HF EKE while barotropic conversion, interaction between HF and IF eddies, and energy flux convergence all play non-negligible roles in determining the final meridional structure of the HF EKE anomalies. Associated with El Niño, IF EKE generally decreases over the North Pacific and increases over the North Atlantic, which mainly result from changes in baroclinic conversion and EKE conversion due to eddy–eddy interactions. The latter is dominated by interaction between IF and LF (low-frequency, 30–90 days) eddies over the North Pacific, and by interactions between HF and IF eddies, and between IF and LF eddies over the North Atlantic.  相似文献   

CO2驱微观可视化技术在超低渗储层中的应用可行性研究:以鄂尔多斯盆地为例     

李明  朱玉双  李文宏  袁国伟  杜朝锋 《现代地质》2019,33(4):911-918

CO₂驱油是提高特低渗、超低渗油藏驱油效率的重要途径,但目前由于匮乏CO₂驱油微观可视化实验技术,制约了CO₂驱油微观机理研究及驱油效果评价。本研究提出特低、超低渗油藏高温高压下CO₂驱油微观可视化实验技术,为该类油藏CO₂驱油机理研究提供良好的研究手段。以鄂尔多斯盆地超低渗储层为例,利用首次研制成功的高温、高压、防暴真实砂岩模型,成功进行了CO₂驱油微观可视化实验研究,首次镜下观察不同相态CO₂在超低渗储层复杂孔喉中驱替原油的动态现象,重新认识超低渗油藏注CO₂驱油时不同孔喉结构中CO₂赋存状态和渗流规律。结果表明,储层微观孔喉结构,尤其是孔喉大小分布的均匀程度,对CO₂驱油效率的重要影响超出预期,直接决定着CO₂能否进入储层以及其后的渗流路径。CO₂驱油微观可视化实验技术可有效进行CO₂驱油微观机理研究及驱油效果评价研究,并为后期进行油藏矿场试验提供指导意见。  相似文献   

Understanding coastal wetland hydrology with a new regional‐scale,process‐based hydrological model          下载免费PDF全文

Yu Zhang  Wenhong Li  Ge Sun  Guofang Miao  Asko Noormets  Ryan Emanuel  John S. King 《水文研究》2018,32(20):3158-3173

Coastal wetlands represent an ecotone between ocean and terrestrial ecosystems, providing important services, including flood mitigation, fresh water supply, erosion control, carbon sequestration, and wildlife habitat. The environmental setting of a wetland and the hydrological connectivity between a wetland and adjacent terrestrial and aquatic systems together determine wetland hydrology. Yet little is known about regional‐scale hydrological interactions among uplands, coastal wetlands, and coastal processes, such as tides, sea level rise, and saltwater intrusion, which together control the dynamics of wetland hydrology. This study presents a new regional‐scale, physically based, distributed wetland hydrological model, PIHM‐Wetland, which integrates the surface and subsurface hydrology with coastal processes and accounts for the influence of wetland inundation on energy budgets and evapotranspiration (ET). The model was validated using in situ hydro‐meteorological measurements and Moderate Resolution Imaging Spectroradiometer (MODIS) ET data for a forested and herbaceous wetland in North Carolina, USA, which confirmed that the model accurately represents the major wetland hydrological behaviours. Modelling results indicate that topographic gradient is a primary control of groundwater flow direction in adjacent uplands. However, seasonal climate patterns become the dominant control of groundwater flow at lower coastal plain and land–ocean interface. We found that coastal processes largely influence groundwater table (GWT) dynamics in the coastal zone, 300 to 800 m from the coastline in our study area. Among all the coastal processes, tides are the dominant control on GWT variation. Because of inundation, forested and herbaceous wetlands absorb an additional 6% and 10%, respectively, of shortwave radiation annually, resulting in a significant increase in ET. Inundation alters ET partitioning through canopy evaporation, transpiration, and soil evaporation, the effect of which is stronger in cool seasons than in warm seasons. The PIHM‐Wetland model provides a new tool that improves the understanding of wetland hydrological processes on a regional scale. Insights from this modelling study provide benchmarks for future research on the effects of sea level rise and climate change on coastal wetland functions and services.  相似文献   

Time-averaged sub-layer concentration profiles in oscillatory sheet flows     

Yuhai Wang  Wenhong Cao  Wen Lu  Huifeng Liu  Gauhu Sun  Chonghao Wang  Fei Liu 《国际泥沙研究》2018,33(4):433-440

Although thin on the order of several to tens of millimeters, sheet flows normally comprise a lower pick-up sub-layer and an upper contact-load sub-layer, separated at the bed level (z = 0). The time-averaged concentration profile in the pick-up sub-layer shows a ‘convex upward’ curvature, but ‘concave upward’ shape characterizes the time-averaged concentration profile in the contact-load sub-layer. The time-dependent concentration in the contact-load sub-layer is approximately in-phase with the free stream flow velocity, whereas it is nearly in anti-phase with the free stream flow velocity in the pick-up sub-layer. Two distinct analytical expressions of the time-averaged concentration profiles for the respective sub-layers are proposed. The expressions are validated with detailed observation datasets collected in the Groβer Wellenkanal (GWK) prototype wave flume in Hannover, Germany. The agreement between the predicted and the measured values is excellent. Interparticle collisions in the pick-up sub-layer and convective lifting processes associated with vortex shedding in the contact-load sub-layer are considered responsible for the opposite curvatures and in-phase/anti-phase concentration variations. Both transitional boundary and reference concentration are also elaborated.  相似文献   

Investigation of three-dimensional circulation and hydrography over the Pearl River Estuary of China using a nested-grid coastal circulation model     

Liqun Tang  Jinyu Sheng  Xiaomei Ji  Wenhong Cao  Dabin Liu 《Ocean Dynamics》2009,59(6):899-919

The Pearl River Estuary (PRE) in South China's Guangdong Province is a subtropical estuary with highly irregular topography and dynamically complicated circulations. A nested-grid coastal circulation modelling system is used in this study to examine dynamic responses of the PRE to tides, meteorological forcing and buoyancy forcing. The nested-grid modelling system is based on the Princeton Ocean Model and consists of three downscaling subcomponents: including an outer-most model with a coarse horizontal resolution of ~7 km for simulating tidally forced and wind-driven surface elevations and depth-mean currents over the China Seas from Bohai Sea to the northern South China Sea and an innermost model with a fine resolution of ~1.2 km for simulating the 3D coastal circulation and hydrography over the PRE and adjacent coastal waters. Model results during the winter northeast monsoon surge in January and super typhoon Koryn in June of 1993 are used to demonstrate that the 3D coastal circulation and hydrographic distributions in the PRE are affected by tides, winds and buoyancy forcing associated with river discharge from the Pearl River with significant seasonal and synoptic variabilities.  相似文献   

利用Χ~2分布确定多元地球化学异常的方法     

Piao Shoucheng Tao Wenhong Lian Changyun 《吉林地质》1997,(3)

与单元素的概率格纸图解法相似，利用Ｘ２分布可直观地识别多元离群样品和进行多重总体分布。在研究多元地球化学异常时，首先运用Ｘ２分布图确定正常总体，然后确定多元正常总体的平均值向量、斜方差矩阵和马氏距离的背景上限值，最后利用这些正常总体的参数计算全域的马氏距离并圈定多元地球化学异常。  相似文献