南大洋气旋气候与变化特征   总被引：2，自引：1，他引：1  

魏立新  秦听 《海洋学报(英文版)》2016,35(7):59-67

A new climatology of cyclones in the Southern Ocean is generated by applying an automated cyclone detection and tracking algorithm(developed by Hodges at the Reading University) for an improved and relatively highresolution European Centre for Medium-Range Weather Forecasts atmospheric reanalysis during 1979–2013.A validation shows that identified cyclone tracks are in good agreement with a available analyzed cyclone product.The climatological characteristics of the Southern Ocean cyclones are then analyzed,including track,number,density,intensity,deepening rate and explosive events.An analysis shows that the number of cyclones in the Southern Ocean has increased for 1979–2013,but only statistically significant in summer.Coincident with the circumpolar trough,a single high-density band of cyclones is observed in 55°–67°S,and cyclone density has generally increased in north of this band for 1979–2013,except summer.The intensity of up to 70% cyclones in the Southern Ocean is less than 980 h Pa,and only a few cyclones with pressure less than 920 h Pa are detected for1979–2013.Further analysis shows that a high frequency of explosive cyclones is located in the band of 45°–55°S,and the Atlantic Ocean sector has much higher frequent occurrence of the explosive cyclones than that in the Pacific Ocean sector.Additionally,the relationship between cyclone activities in the Southern Ocean and the Southern Annular Mode is discussed.  相似文献   

层结稳定性“豁口”与北太平洋副热带中部模态水形成机制          下载免费PDF全文

潘爱军  刘秦玉  刘征宇 《地球物理学报》2008,51(1):77-87

本文首先指出北太平洋副热带中部模态水（简称中部模态水）的形成具有显著的“局地”特征,其形成海区在（165°E～160°W,38°N～42°N）区间. 海气通量分析表明单纯的外部大气强迫场（太阳短波辐射、净热通量和风应力旋度）不能解释中部模态水形成海区的“局地”性;进一步对上层海洋层结季节变化特征的分析发现秋季（9～10月）在北太平洋中部上层海洋（<75 m）（165°E～160°W,38°N～42°N）区间存在特殊的浮力频率低值区——层结稳定性“豁口”. 该层结稳定性“豁口”作为“预条件（Precondition Mechanism）”机制对中部模态水形成的“局地”特征给出了合理的解释. 在上述研究的基础上,基于一个上层海洋混合层热平衡方程,通过诊断分析揭示该层结稳定性“豁口”是由海表热力强迫、垂向挟卷、Ekman平流和地转平流效应共同导致的,“豁口”东、西边界的确定直接或间接地取决于海表热力强迫、Ekman冷平流和地转暖平流的纬向分布差异.  相似文献   

A Study of a Short-Baseline Acoustic Positioning System for Offshore Vessels     

Cho-Chung Liang 《Marine Geodesy》1999,22(1):19-30

The underwater position of the beacon determined using the conventional mode of the short-baseline acoustic positioning system (SBL system) is usually incorrect due to the inaccuracy of underwater-measured sound speed, which is affected by the environment. This article presents a corrected mode of SBL system to offer a precise solution for the underwater beacon position. The corrected mode using the formulation of Euclidean geometry converges quickly and efficiently, obtaining the precise position of the beacon. Finally, a simulation of coring missions of a vessel is presented to verify the accuracy of the corrected mode of the SBL system.  相似文献   

A Synoptic Snapshot of the East Cape Eddy （ECE）     

LIU Wei  and LIU Qinyu Physical Oceanography Laboratory & Ocean-Atmosphere Interaction  Climate Laboratory  Ocean University of China  Qingdao  P. R. China 《中国海洋大学学报(英文版)》2005,4(1):8-13

1Introduction The East Australian Current(EAC)partially sepa-rates from the coast of Australia(Godfrey et al.,1980)and subsequently flows eastward along the Tas-man Front(TF)(Warren,1970).When the east-ward flow reaches the northernmost point of New Zealand,it turns southeastward and becomes the East Auckland Current(EAUC).The flow that goesround the East Cape is named the Ease Cape Current(ECC).The ECC separates from North Island and proceeds eastward to the north of the Chatha…  相似文献   

邵阳竹文化生态旅游开发   总被引：3，自引：0，他引：3  

马文银 《热带地理》2005,25(3):278-282

邵阳市竹文化具有悠久的历史、优美的自然景观、意味无穷的竹景文化艺术、源远流长的竹工艺文化和绿色饮食文化等特色。将竹文化和生态旅游结合形成一种新型特色旅游模式加以研究开发,对地方旅游经济发展颇有指导意义。文中阐述竹文化生态旅游的概念、基本特征和意义,具体分析了邵阳发展竹文化生态旅游的优势,提出了邵阳竹文化生态旅游开发以欣赏观光型、休闲体验型和文化商贸型为主的基本模式及应采取的相应对策。  相似文献   

Spatial structure and stability of coupled Alfvén and drift compressional modes in non-uniform magnetosphere: Gyrokinetic treatment     

Dmitri Yu. Klimushkin  Pavel N. Mager 《Planetary and Space Science》2011,59(13):1613-1620

The spatial structure and stability properties of the coupled Alfvén and drift compressional modes in a space plasma are studied in a gyrokinetic framework in a model taking into account field-line curvature and plasma and magnetic field inhomogeneity across the magnetic shells. The perturbation is found to be localized in two transparent regions, the Alfvén and drift compressional transparent regions, where the wave vector radial component squared is positive. Both regions are bounded by the resonance and cut-off surfaces, where the wave vector radial component turns into infinity and zero, respectively. An existence of the drift compressional resonance is one of the most important results of this work. It is argued that on the surface of this resonance the longitudinal and azimuthal components of the wave's magnetic field have a pole and logarithmic singularities, respectively. The instability conditions and expressions for the growth rate of the coupled modes have been obtained. In the Alfvénic transparent region, an instability occurs in the presence of the negative plasma temperature gradient. This instability does not lead to a non-stationary wave behavior: all the energy gained from the resonance particles was finally absorbed owing to any dissipation process. In a drift compressional transparent region, a necessary condition for the instability is the growth of the temperature with the radial coordinate. The growth rate is almost independent of the radial coordinate, which means that the wave energy gained from the particles cannot disappear. It will lead to an ever increasing wave amplitude, and no stationary picture for the unstable drift compressional mode is possible.  相似文献   

Facility allocation strategies and the sustainability of service delivery: Modelling library patronage patterns and their related CO2-emissions     

《Applied geography (Sevenoaks, England)》2013

Service accessibility and urban transportation choices are crucial in cities' endeavours for securing social equality and environmental sustainability. They are particularly relevant when the public service network is to be rationalized. In this paper we provide a practical example of comparing the impacts of current varying service allocation strategies on travel behaviour and the resulting carbon dioxide (CO₂) emissions. We take libraries as a local public service to examine the CO₂ emissions resulting from residents' library trips in the capital region of Finland. Our analyses are based on data on library use (library loan database, N = 420,000), accessibility (comparable models of travel-time by car, public transportation and non-motorized transport) and customer transport choices (survey, n = 584). Our results show that (1) 52% of library customers use a library that is accessible from their home with minimum CO₂ emissions (the “climate-optimal” facility provider), (2) the remaining 48% that choose a non-optimal facility provider produce nearly 90% of the total CO₂-emissions related to library customer flows and (3) the service allocation strategies of the different municipalities lead to markedly different CO₂-emission patterns resulting from service usage. To conclude, sustainability measures (in our case the CO₂ burden) provide useful information on the impact of a service network structure which may be used alongside economic rationales.  相似文献   

中国农业产业集群演化过程及创新发展机制——以“寿光模式”蔬菜产业集群为例   总被引：3，自引：1，他引：2  

李二玲 《地理科学》2020,40(4):617-627

在对农业产业集群理论探讨的基础上,以山东寿光蔬菜产业集群为例,分析中国农业产业集群形成演化的“四阶段”模型及可持续创新发展的内在机制,并挖掘了“寿光模式”的“集群”本质。结论表明: ① 中国农业产业集群的形成与创新发展:首先是从农业产业集聚开始,并经由专业村到产业集群,再到乡村创新极演化; ② 促进农户的企业化演变是农业集群及其创新体系形成的第一步。创建产业网络是农业产业集聚和专业村向农业产业集群升级的必备步骤,农业创新体系的形成标志着农业集群走向成熟; ③ 山东寿光蔬菜产业集群的形成演化也经历了这4个阶段。各类各层主体通过知识增长、知识流动和知识采纳提高自己的内生能力和外部契约关系,并通过知识和创新网络实现五大维度上的协同创新,一起促进企业（农户）、产业（网络）、技术、制度和空间“五位一体”的协同演化,是农业集群可持续创新发展的内在机制。  相似文献   

A two-way stratosphere-troposphere coupling of submonthly zonal-mean circulations in the Arctic     

李晓峰  李建平 《大气科学进展》2013,30(6):1771-1785

This paper examines the dominant submonthly variability of zonally symmetrical atmospheric circula- tion in the Northern Hemisphere （NH） winter within the context of the Northern Annular Mode （NAM）, with particular emphasis on interactive stratosphere-troposphere processes. The submonthly variability is identified and measured using a daily NAM index, which concentrates primarily on zonally symmetrical circulation. A schematic lifecycle of submonthly variability is developed that reveals a two-way coupling pro- cess between the stratosphere and troposphere in the NH polar region. Specifically, anomalous tropospheric zonal winds in the Atlantic and Pacific sectors of the Arctic propagate upwards to the low stratosphere, disturbing the polar vortex, and resulting in an anomalous stratospheric geopotential height （HGT） that subsequently propagates down into the troposphere and changes the sign of the surface circulations. From the standpoint of planetary-scale wave activities, a feedback loop is also evident when the anoma- lous planetary-scale waves （with wavenumbers 2 and 3） propagate upwards, which disturbs the anomalous zonally symmetrical flow in the low stratosphere, and induces the anomalous HGT to move poleward in the low stratosphere, and then propagates down into the troposphere. This increases the energy of waves at wavenumbers 2 and 3 in the low troposphere in middle latitudes by enhancing the land-sea contrast of the anomalous HGT field. Thus, this study supports the viewpoint that the downward propagation of stratospheric NAM signals may not originate in the stratosphere.  相似文献   

德国不动产登记制度概况     

李茂 《国土资源情报》2014,(7):32-36

德国不动产登记历史悠久,法律体系健全,《土地登记条例》、《德国民法典》、《德国物权法》等对不动产登记做出了具体规定,在不动产登记模式、登记机关、不动产登记簿和不动产登记赔偿等方面对于建立我国的不动产登记体系有一定的借鉴意义。  相似文献