渤海海峡跨海通道建设对城市经济联系的影响分析          下载免费PDF全文

狄乾斌  马洁 《海洋开发与管理》2018,35(3):102-108

渤海海峡跨海通道建设将极大改变环渤海乃至整个东部沿海的交通格局,势必对其目标城市大连、烟台带来直接的经济影响,同时也会对辽东半岛、山东半岛乃至东北、华北和华东不同尺度地区的经济联系产生深远影响。文章选取山东省17个和辽宁省14个地级市的地区的生产总值、城市人口以及城市间的最短时间距离等指标,测度渤海海峡跨海通道建成前后,对山东、辽宁两省区域城市经济联系的影响。研究表明:渤海海峡跨海通道建成后,对大连、烟台间的经济联系强度有显著提高,各城市经济联系度的平均增幅明显不同;同时,受距离衰减规律的影响,两省的城市分别以大连、烟台为中心,根据距离远近及城市自身发展程度分为4个层次,经济联系强度由内向外逐层次减弱;从整体上看,渤海通道的建设对带动两省城市之间的经济联系度都有大幅度提升。  相似文献   

基于机载微波辐射计探测大气水汽通道饱和问题研究     

王婉  雷恒池  聂皓浩  王兆宇  郭晓军 《气象学报》2021,79(3):509-520

183.31 GHz微波辐射计在探测低含量水汽时具有优势,但也存在通道饱和问题,定量研究该问题对明确该类型仪器探测水汽能力和适用范围具有重要意义。基于天津市人工影响天气办公室增雨飞机运-12搭载的183.31 GHz微波辐射计GVR（G-band water Vapor Radiometer）,采用探空资料对该辐射计4个通道进行饱和问题研究,定量计算其饱和阈值及探测灵敏度,分析各通道水汽探测能力及适用范围。结果表明:机载微波辐射计4个通道水汽探测灵敏度及饱和阈值与观测高度有关,当水汽含量较低时,通道1（（183±1）GHz）观测高度越高灵敏度越高,通道3（（183±7）GHz）和通道4（（183±14）GHz）观测高度越高灵敏度越低,通道2（（183±3）GHz）灵敏度几乎不受观测高度影响,通道1和通道4观测高度越高积分水汽探测饱和阈值越小,观测高度越低饱和阈值越大,通道2和通道3饱和阈值几乎不受观测高度影响。晴空条件下选择水汽探测能力最强的单通道对积分水汽含量进行反演,当积分水汽含量处于0—1.3、1.3—4.0和4.0—9.8 mm时,分别选择通道1、通道2、通道3作为反演通道,不同观测高度的积分水汽含量反演均适用。云的发射作用使辐射计各通道亮温升高,亮温升高幅度与云液态水含量、云与观测高度的距离及云厚有关,云液态水含量越大,各通道水汽探测灵敏度及饱和阈值越小;云天条件下选择水汽探测能力最强的双通道对积分水汽含量进行反演,以液态水路径区间来选择合适的水汽探测通道,液态水含量越高,积分水汽可探测范围越小。要探测到0.1 mm的积分水汽含量变化,机载微波辐射计（GVR）在晴空条件下的水汽探测适用范围为0—9.8 mm,其探测能力在云天条件下减弱,水汽探测适用范围因云液态水含量不同而不同。   相似文献   

曲流河扇相模式及应用     

张金亮 《地质论评》2022,68(1):2022010017-2022010017

分支河流体系的讨论有助于促进各类冲积体系的分类学研究,并可促进源—汇体系分析的定量化。博茨瓦纳的奥卡万戈（Okavango）曲流河扇是分支河流体系的典型代表,具有独特的沉积学、水文学和地貌学特征,主要特点如下：①河道形态属于单线曲流河道向下游分叉型,顺流方向产生弯度不一的分支河道网络,从顶点向下游方向,河道呈放射状,由河谷内的限制性河道变为盆地内的非限制性河道;②顺斜坡向下,河道分叉作用增强,河道的尺度和规模减小,受物源控制,无论是曲流河道还是低弯度河道,皆为砂质载荷,河道宽度、水体深度和沉积物粒度虽有系统变化但不显著,且在极低的坡度控制下,随着流量的减少,河道由曲流河逐渐变为低弯度河,河道形态转化的主要影响因素是坡度、流量、沉积物粒级和河岸强度;③根据湿地和河道分布特征,可将扇体划分为补给河谷、近源扇、中部扇和远端扇4个亚环境：补给河谷以单线曲流带和不同规模的迂回坝发育为特征,近源扇主要为泥炭限制的分支河道和河间沼泽沉积,中部扇主要为曲流河和低弯度河沉积,沼泽减少,漫滩增加,远端扇为宽浅型的非限定性河道,以沙岛林地之间的漫滩沉积为主;④沉积物主要为未固结的石英砂,主要来源于卡拉哈里盆地近代风成沉积,砂质纯净,分选和磨圆俱佳,缺乏细粒杂基,粒间细粒组分主要为生物成因的硅藻、植硅石和有机物质,亦见有方解石和二氧化硅胶结物。  对现代曲流河扇体系进行调查的重要目的就是研究地下类似沉积体系的分布。通过对我国大型含油气盆地相关“内陆三角洲”沉积特征和沉积规律的重新认识,可为油气资源的勘探开发提供预测模式。鄂尔多斯盆地山西组沉积时期,沉积作用受盆地北缘物源控制,来自北部物源的碎屑物质在宽阔的湿地平原上发育了多套分支河流沉积体系,主要为曲流河扇沉积体系。顺着沉积斜坡向下,河道的尺度和规模减小,沉积物粒度变细,煤层和暗色泥岩厚度变小,缺乏明显的三角洲前缘沉积环境及稳定的前三角洲深水相。沉积组合主要表现为分支河道砂岩、漫岸细粒沉积与湿地泥岩及薄煤层的互层,为大气田的形成奠定了沉积基础。  相似文献   

山西省地热资源规律及其地质背景研究     

李壮 《地质与勘探》2023,59(2):353-376

中国大陆蕴藏丰富的地热资源,山西省局部地热异常特征明显。通过收集山西省典型地热区域流体数据,选取典型钻孔分析,探讨并总结山西省地热资源赋存规律和成因机制,为后期地热资源勘探及开发利用提供重要参考依据。通过分析研究结果得出以下几点认识：山西省水热型地热储层水温分布在28～78℃,北部以太古代花岗片麻岩为主,中部以古生代灰岩为主,南部以古生代碳酸盐岩为主;北部热源主要来自花岗岩中放射性元素衰变产生热量,中部和南部热源受地幔上隆及岩浆活动影响;省内深大断裂构成地下热水运移通道,热传导性较好;第四纪和第三纪松散层为省内地热良好的保温盖层,岩性以粘土、砂质粘土及砂层为主。结合前人水文地球化学研究成果,认为山西省地热水pH值呈弱碱性,其中Sr、Li、SiO₂与Cl大体上存在正相关关系,大部分地热水氚含量小于1TU,水源主要为大气降水补给,部分地热田出现δ¹⁸O漂移,氧同位素交换作用显著。  相似文献   

Feeding strategies of deep-sea sub-Arctic macrofauna of the Faroe-Shetland Channel: Combining natural stable isotopes and enrichment techniques     

E. Gontikaki  D.J. MayorB.E. Narayanaswamy  U. Witte 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(2):160-172

The response of a sub-arctic, deep-sea macrofaunal community to a simulated food sedimentation event was studied by means of a stable isotope “pulse-chase” experiment. A food pulse was simulated by adding 500 mg C m⁻² of ¹³C-labelled diatoms, Chaetoceros radicans, to sediment cores retrieved from 1080 m in the Faroe-Shetland Channel. Carbon uptake by specific macrofaunal groups was quantified after 3 and 6 days of incubation. The carbon uptake of the dominant taxon (Polychaeta) was quantified at the genus-, and where possible, species-level, representing a data resolution that is rare in deep-sea tracer studies. The macrofaunal community reacted rapidly to the diatom addition, with 47% and 70% of the animals illustrating ¹³C-enrichment after 3 and 6 days, respectively. Approximately 95% of C uptake was located in the upper 2 cm due to the particularly shallow vertical distribution of the macrofaunal community and the nonexistent tracer subduction by burrowing species. Polychaetes of the families Ampharetidae and Cirratulidae were among the most heavily labelled with above background enrichment reaching 1300‰. Approximately 0.8 and 2.0 mg C m⁻² were processed by the macrofauna after 3 and 6 days, representing 0.2% and 0.4% of the added carbon, respectively. It was not possible to differentiate sub-surface deposit-feeding polychaetes from predator/scavenger- and omnivorous polychaetes using their natural ??¹⁵N signatures. However, the combination of natural abundance ??¹⁵N data and ¹³C-labelling experiments proved to be useful for elucidating trophic relations in deep-sea food webs. This study confirms that macrofauna play an active role in the short-term carbon cycling at bathyal depths even at sub-zero temperatures and highlights the need for detailed knowledge of the community structure in understanding carbon processing patterns and early diagenesis of organic matter in marine sediments.  相似文献   

阜新矿震台网无线信道测试     

王学成  刘一萌  唐喆  李秀丽  雷晨 《内陆地震》2011,25(2):185-190

为了提高矿震台网的运行率,保障地震数据的连续率、完整率,对阜新矿震台网的信道进行了测试,主要包括制作传播路径地形剖面图以了解信道传输的视通条件、对信道传播损耗的理论计算及功率储备的测量、进行接收场强及背景干扰的测试以确定传输频点。结果显示,阜新矿震台网无线传输信道的场强在50~73 dB之间,能够保证无线信号传输质量,符合遥测台网建设技术规范要求。  相似文献   

Morphological and sedimentary impacts and recovery on a mixed sandy to pebbly seabed exposed to marine aggregate extraction (Eastern English Channel,France)     

Sophie Le Bot  Robert Lafite  Matthieu Fournier  Agnès Baltzer  Michel Desprez 《Estuarine, Coastal and Shelf Science》2010

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A comparison of the main methods for estimating probabilities of extreme still water levels     

Ivan D. Haigh  Robert Nicholls  Neil Wells 《Coastal Engineering》2010

Sea-level return periods are estimated at 18 sites around the English Channel using: (i) the annual maxima method; (ii) the r-largest method; (iii) the joint probability method; and (iv) the revised joint probability method. Tests are undertaken to determine how sensitive these four methods are to three factors which may significantly influence the results; (a) the treatment of the long-term trends in extreme sea level; (b) the relative magnitudes of the tidal and non-tidal components of sea level; and (c) the frequency, length and completeness of the available data. Results show that unless sea-level records with lengths of at least 50 years are used, the way in which the long-term trends is handled in the different methods can lead to significant differences in the estimated return levels. The direct methods (i.e. methods i and ii) underestimate the long (> 20 years) period return levels when the astronomical tidal variations of sea level (relative to a mean of zero) are about twice that of the non-tidal variations. The performance of each of the four methods is assessed using prediction errors (the difference between the return periods of the observed maximum level at each site and the corresponding data range). Finally, return periods, estimated using the four methods, are compared with estimates from the spatial revised joint probability method along the UK south coast and are found to be significantly larger at most sites along this coast, due to the comparatively short records originally used to calibrate the model in this area. The revised joint probability method is found to have the lowest prediction errors at most sites analysed and this method is recommended for application wherever possible. However, no method can compensate for poor data.  相似文献   

Turbulent structure in uniform inclined open channel flow over different rough porous beds     

Evangelos Keramaris 《国际泥沙研究》2017,32(1)

In this study the effects of the different rough porous beds in an open inclined channel are studied experimentally for impermeable and permeable porous bed.For the simulation of porous bed two different types of permeable bed with the same thickness(s' = 3 cm) and the same porosity ε=0.70 are used:(a) porous filters and(b) gravel bed.Laboratory experiments were used for the calculation of turbulent velocity profiles.Measurements of velocity were taken for inclined channel for three different slopes(S=-0.002,S=-0.004 and S=-0.006) and for five different flow depths(h=5 cm,7 cm,9 cm,11 cm and 13 cm).The total discharge Q varies from 0.78 to 1.31 1/s.The measurements were obtained using a two-dimensional(2D) Particle Image Velocimetry(PIV).The total discharge was estimated using a calibrated venture apparatus.Results showed that the presence of rough porous bed in inclined open channels influence significantly the turbulent characteristics of the flow in comparison with impermeable open channels with the same slopes.  相似文献   

Macrozoobenthic biomass in the Bay of Seine (eastern English Channel)   总被引：1，自引：0，他引：1  

Jean-Claude Dauvin  Thierry Ruellet 《Journal of Sea Research》2008,59(4):320-326

The benthic biomass values of various trophic groups were studied for the first time at the scale of the entire Bay of Seine (50 × 100 km) in the eastern English Channel. Sampling was carried out before and after the winter of 1999. In both cruises the suspension feeders dominated (66% of the 12 gAFDW m^− 2 in 1998 and 56% of the 10 gAFDW m^− 2 in 1999).The common European ophiuroid Ophiothrix fragilis was the most important contributor to total biomass. The repartition of its patches (sometimes > 20 gAFDW m^− 2) cannot be explained by the environmental parameters recorded (viz., granulometry, organic matter and pigment content).  相似文献