有限区域大气-海浪耦合模式的建立及海表粗糙度参数化试验   总被引：1，自引：0，他引：1       下载免费PDF全文

关皓  周林  王汉杰  景丽 《海洋学报》2008,30(4):30-38

利用LINUX操作系统下的进程通讯(IPC)技术将中尺度大气模式MM5(V3)与第三代海浪模式WW3进行双向耦合,建立考虑大气-海浪相互作用的风浪耦合模式,在耦合模式中引入3种海表粗糙度参数化方案,通过对一次热带气旋过程的模拟,研究大气-海浪相互作用对热带气旋系统的影响及耦合模式对海表粗糙度参数化方案的敏感性。结果表明:LINUX系统下的进程通讯技术可以方便有效地实现大气和海浪模式的双向耦合,模式运行稳定;耦合模式能够较好的模拟热带气旋的发展和演变过程及其影响下海浪场的分布和演变,模拟结果对海表粗糙度参数化方案较敏感;海浪的反馈作用同时影响了海气间的动力和热力作用过程,不同的海表粗糙度参数化方案下,海浪对两种作用过程不同的影响程度决定了其对气旋系统强度的影响。  相似文献   

利用机载GNSS反射信号反演海面风速的研究   总被引：2，自引：0，他引：2  

王迎强  严卫  符养  李萍 《海洋学报》2008,30(6):51-59

全球卫星导航定位系统的反射信号(GNSS-R)遥感技术作为一种新型的、低成本的、高机动性的海面微波遥感测风技术,与其他测风手段优势互补,可以增加测风手段的多样性,弥补局部测风手段不足的状况。研究了接收机在机载高度时,GPS反射信号功率理论模型四部分函数的性质,在此基础之上,数值模拟了机载高度下理论相关功率波形,基于海面风速对波形峰值与后沿的影响,提出了一种能够兼顾所有理论波形信息的二维插值风速反演方法。利用该方法,结合实测机载数据对海面风速进行反演,反演的风速均值与附近测站风速均值相差为1.4 m/s,与浮标数据相一致。  相似文献   

Surface current field and seasonal variability in the Kuroshio and adjacent regions derived from satellite-tracked drifter data   总被引：7，自引：2，他引：5  

HU Xiaomin  XIONG Xuejun  QIAO Fangli  GUO Binghuo  LIN Xiaopei 《海洋学报(英文版)》2008,27(3):11-29

The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and （1/4） ° latitude by （1/4） ° longitude mean currents derived from 323 Argos drifters deployed by Chinese institutions and world ocean circulation experiment from 1979 to 2003. The results show that the Kuroshio surface path adapts well to the western boundary topography and exhibits six great turnings. The branching occurs frequently near anticyclonic turnings rather than near cyclonic ones. In the Luzon Strait, the surface water intrusion into the South China Sea occurs only in fall and winter. The Kuroshio surface path east of Taiwan, China appears nearly as straight lines in summer, fall, and winter, when anticyclonic eddies coexist on its right side; while the path may cyclonically turning in spring when no eddy exists. The Kuroshio intrusion northeast of Taiwan often occurs in fall and winter, but not in summer. The running direction, width and velocity of the middle segment of the Kuroshio surface currents in the East China Sea vary seasonally. The northward intrusion of the Kuroshio surface water southwest of Kyushu occurs in spring and fall, but not in summer. The northmost position of the Kuroshio surface path southwest of Kyushu occurs in fall, but never goes beyond 31 °N. The northward surface current east of the Ryukyu Islands exists only along Okinawa-Amami Islands from spring to fall. In particular, it appears as an arm of an anti- cyclonic eddy in fall.  相似文献   

Simplified Calculation Method and 3D Numerical Analysis for Pile Group Under Uplift Loading     

孔纲强  杨庆  刘汉龙  栾茂田 《中国海洋工程》2009,23(4):709-718

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“源-汇”景观格局的热岛效应研究——以武汉市为例   总被引：1，自引：0，他引：1  

高静  龚健  李靖业 《地理科学进展》2019,38(11):1770-1782

论文基于2017年Landsat 8遥感影像,通过GIS技术选取城市地表温度、源汇景观密度、源汇景观贡献度和景观效应指数,结合地理空间分析和数理统计方法,分析了武汉市局部源汇景观格局对城市地表温度的贡献及其效应。结果表明：① 武汉市城区热岛(urban heat island, UHI)季节变化明显,夏季热岛强度大、范围广,呈“大”字型分布,工业集聚区和经济开发区产生的UHI更显著;② 武汉市城区平均地表温度(land surface temperature, LST)在距市中心约8 km处达到峰值后沿城乡梯度逐渐下降,呈现“倒钩型”特征,这一现象与景观密度变化密切相关;③ LST与源(正向)、汇(负向)景观密度存在极强相关性,不透水表面是城区热岛的主要贡献因子;④ 相同密度的水体和绿地,水体更具有削弱城市热岛效应的功能;⑤ 一般当汇-源景观面积比>0.89(汇区密度>0.47)时,局部景观格局对城市热岛有缓解作用,且局部汇区越集中缓解效果越显著。  相似文献   

双重投影在高速铁路测量中的应用分析     

刘灵杰  卫建东  白振慧 《测绘学院学报》2009,(2)

针对目前我国高速铁路测量采用的高斯投影独立坐标系每个投影带可控制范围太小,给施工带来很多不便的问题,提出了首先将椭球面经纬度投影至球面后再沿铁路线方向进行斜墨卡托投影的原理、方法和计算步骤,并通过算例分析其在高速铁路测量应用中的可行性,该投影方法与目前施工单位正在使用的高斯投影相比较具有明显的优点。  相似文献   

Examining the sensitivity of spatial scale in cellular automata Markov chain simulation of land use change   总被引：2，自引：0，他引：2  

Hao Wu  Zhen Li  Keith C. Clarke  Wenzhong Shi  Anqi Lin 《International journal of geographical information science》2019,33(5):1040-1061

Understanding the spatial scale sensitivity of cellular automata is crucial for improving the accuracy of land use change simulation. We propose a framework based on a response surface method to comprehensively explore spatial scale sensitivity of the cellular automata Markov chain (CA-Markov) model, and present a hybrid evaluation model for expressing simulation accuracy that merges the strengths of the Kappa coefficient and of Contagion index. Three Landsat-Thematic Mapper remote sensing images of Wuhan in 1987, 1996, and 2005 were used to extract land use information. The results demonstrate that the spatial scale sensitivity of the CA-Markov model resulting from individual components and their combinations are both worthy of attention. The utility of our proposed hybrid evaluation model and response surface method to investigate the sensitivity has proven to be more accurate than the single Kappa coefficient method and more efficient than traditional methods. The findings also show that the CA-Markov model is more sensitive to neighborhood size than to cell size or neighborhood type considering individual component effects. Particularly, the bilateral and trilateral interactions between neighborhood and cell size result in a more remarkable scale effect than that of a single cell size.  相似文献   

高速铁路对东北城市网络结构的空间影响   总被引：2，自引：0，他引：2  

刘书舟  韩增林  郭建科 《地理科学》2020,40(2):270-279

借鉴复杂网络理论,以铁路列车时刻表为基础数据,探讨高速铁路的开通对东北地区铁路网络结构和城市网络结构的空间影响。结果表明：① 高铁强化了东北地区铁路网络的小世界、无标度等网络特征,各网络节点在可达性和辐射能力方面受到4种不同形式的影响;② 高铁强化了沈阳和哈尔滨的主-副双核心铁路网络结构,使得拓扑网络的离散程度大幅降低,长春、大连等城市的网络联系中心性显著提升;③ 铁路交通重心向西北方向偏移,区域间不平衡性增强,吉林省成为东北铁路客运联系强度最高的地区;④ 大连市拥有特殊的门户城市特征,即对外联通能力强,但未形成足够吸引力。  相似文献   

Late Cretaceous blueschist facies metamorphism in southern Thrace (Turkey) and its geodynamic implications     

G. TOPUZ  A. I. OKAY  R. ALTHERR  M. SATIR  W. H. SCHWARZ 《Journal of Metamorphic Geology》2008,26(9):895-913

A blueschist facies tectonic sliver, 9 km long and 1 km wide, crops out within the Miocene clastic rocks bounded by the strands of the North Anatolian Fault zone in southern Thrace, NW Turkey. Two types of blueschist facies rock assemblages occur in the sliver: (i) A serpentinite body with numerous dykes of incipient blueschist facies metadiabase (ii) a well‐foliated and thoroughly recrystallized rock assemblage consisting of blueschist, marble and metachert. Both are partially enveloped by an Upper Eocene wildflysch, which includes olistoliths of serpentinite–metadiabase, Upper Cretaceous and Palaeogene pelagic limestone, Upper Eocene reefal limestone, radiolarian chert, quartzite and minor greenschist. Field relations in combination with the bore core data suggest that the tectonic sliver forms a positive flower structure within the Miocene clastic rocks in a transpressional strike–slip setting, and represents an uplifted part of the pre‐Eocene basement. The blueschists are represented by lawsonite–glaucophane‐bearing assemblages equilibrated at 270–310 °C and ～0.8 GPa. The metadiabase dykes in the serpentinite, on the other hand, are represented by pumpellyite–glaucophane–lawsonite‐assemblages that most probably equilibrated below 290 °C and at 0.75 GPa. One metadiabase olistolith in the Upper Eocene flysch sequence contains the mineral assemblage epidote + pumpellyite + glaucophane, recording P–T conditions of 290–350 °C and 0.65–0.78 GPa, indicative of slightly lower depths and different thermal setting. Timing of the blueschist facies metamorphism is constrained to c. 86 Ma (Coniacian/Santonian) by Rb–Sr phengite–whole rock and incremental ⁴⁰Ar–³⁹Ar phengite dating on blueschists. The activity of the strike–slip fault post‐dates the blueschist facies metamorphism and exhumation, and is only responsible for the present outcrop pattern and post‐Miocene exhumation (～2 km). The high‐P/T metamorphic rocks of southern Thrace and the Biga Peninsula are located to the southeast of the Circum Rhodope Belt and indicate Late Cretaceous subduction and accretion under the northern continent, i.e. the Rhodope Massif, enveloped by the Circum Rhodope Belt. The Late Cretaceous is therefore a time of continued accretionary growth of this continental domain.  相似文献   

Constraining Holocene sea‐surface conditions in the south‐western Black Sea using dinoflagellate cysts     

L. R. Bradley  F. Marret  P. J. Mudie  A. E. Aksu  R. N. Hiscott 《第四纪科学杂志》2012,27(8):835-843

This paper presents two dinoflagellate cyst records from the south‐western shelf of the Black Sea. A new site, MAR05‐13, from the Sakarya shelf is described and placed into context with site MAR02‐45, ～250 km distant on the Thracian shelf. The records provide a centennial resolution of surface water conditions in the Holocene. Analysis of the data suggests that the surface salinity of the south‐western shelf increased in a gradual and progressive manner. In the period ～11 000–9000 cal a BP the assemblages suggest surface‐water salinities between 7–13 psu. The initial arrival of euryhaline species, ～8100 cal a BP, is linked to the reconnection of the Black Sea and Marmara Sea. The suggested surface water changes related to the reconnection took approximately 1000 years. Following this initial change in assemblages, a further increase in the number of euryhaline species is noted between 5000 and 4000 cal a BP. This is linked to the establishment of more saline surface‐water conditions, close to present‐day values. The record for MAR05‐13 highlights the complexity of the changes in cyst assemblages during the mid‐Holocene. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献