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251.
Sara Jutterström Emil Jeansson Leif G. Anderson E. Peter Jones James H. Swift 《Progress in Oceanography》2008,78(1):78-84
Several methods to compute the anthropogenic component of total dissolved inorganic carbon () in the ocean have been reported, all in some way deducing (a) the effect by the natural processes, and (b) the background concentration in the pre-industrial scenario. In this work we present a method of calculating using nutrient and CFC data, which takes advantage of the linear relationships found between nitrate (N), phosphate (P) and CFC-11 in the Nordic Seas sub-surface waters. The basis of the method is that older water has lower CFC-11 concentration and also has been exposed to more sinking organic matter that has decayed, resulting in the slopes of P versus CFC-11 and N versus CFC-11 being close to the classic Redfield ratio of 1:16. Combining this with the slope in total alkalinity (AT) versus CFC-11 to correct for the dissolution of metal carbonates gives us the possibility to deduce the concentration of anthropogenic CT in the Nordic Seas. This further allowed us to compute the inventory of anthropogenic CT below 250 m in the Nordic Seas in spring 2002, to ∼1.2 Gt C. 相似文献
252.
The influence of distinct demographic factors on determining population size in a littoral nesting fish (Symphodus roissali) was studied. Differences in the overall abundances were studied at three sites in the NW Mediterranean Sea for three years, to examine whether: 1) the adult population determined the number of successful nests; 2) the number of successful nests determined recruitment levels; 3) recruitment levels were subsequently related to the number of young of the year (YOY) joining the population after the recruitment period; and 4) the YOY value determined the size of the year class 1 cohort in the following year's adult reproductive population. The results show that there was a significant relationship between the number of spawners and the number of successful nests. However, the number of successful nests does not always correlate well with recruitment level. Furthermore, recruitment levels are not good indicators of the Young of the Year (measured three months after settlement) in number joining the populations, though YOY in number was related to the strength of the year class joining the adult reproductive population the following year. Therefore, the magnitude of the recruitment and probably the size of the adult population did not determine the year-class strength in S. roissali. 相似文献
253.
关于"生态旅游"概念的探讨 总被引:6,自引:0,他引:6
王家骏 《地理与地理信息科学》2002,18(1):103-106
该文选取国外44个生态旅游定义作为研究对象,通过确认关键词、对关键词进行聚类分析,将定义内容归纳为6大类11组分,进而构建生态旅游概念模型.在检验模型理论上的可靠性和实践上的适应性后,笔者依据模型提出生态旅游定义. 相似文献
254.
Gerrit de Leeuw Leo Cohen Lise Marie Frohn Gary Geernaert Ole Hertel Bjarne Jensen Tim Jickells Laura Klein Gerard J. Kunz Soren Lund Marcel Moerman Frank Müller Britta Pedersen Knut von Salzen K. Heinke Schlünzen Michael Schulz Carsten A. Skjth Lise-Lotte Sorensen Lucinda Spokes Susanne Tamm Elisabetta Vignati 《Continental Shelf Research》2001,21(18-19)
The aim of the atmospheric nitrogen inputs into the coastal ecosystem (ANICE) project is to improve transport–chemistry models that estimate nitrogen deposition to the sea. To achieve this, experimental and modelling work is being conducted which aims to improve understanding of the processes involved in the chemical transformation, transport and deposition of atmospheric nitrogen compounds. Of particular emphasis within ANICE is the influence of coastal zone processes. Both short episodes with high deposition and chronic nitrogen inputs are considered in the project. The improved transport–chemistry models will be used to assess the atmospheric inputs of nitrogen compounds into the European regional seas (the North Sea is studied as a prototype) and evaluate the impact of various emission reduction strategies on the atmospheric nitrogen loads. Assessment of the impact of atmospheric nitrogen on coastal ecosystems will be based on comparisons of phytoplankton nitrogen requirements, other external nitrogen inputs to the ANICE area of interest and the direct nitrogen fluxes provided by ANICE. Selected results from both the experimental and modelling components are presented here. The experimental results show the large spatial and temporal variability in the concentrations of gaseous nitrogen compounds, and their influences on fluxes. Model calculations show the strong variation of both concentrations and gradients of nitric acid at fetches of up to 25 km. Aerosol concentrations also show high temporal variability and experimental evidence for the reaction between nitric acid and sea salt aerosol is provided by size-segregated aerosol composition measured at both sides of the North Sea. In several occasions throughout the experimental period, air mass back trajectory analysis showed connected flow between the two sampling sites (the Weybourne Atmospheric Observatory on the North Norfolk coast of the UK and Meetpost Noordwijk, a research tower at 9 km off the Dutch coast). Results from the METRAS/SEMA mesoscale chemistry transport model system for one of these cases are presented. Measurements of aerosol and rain chemical composition, using equipment mounted on a commercial ferry, show variations in composition across the North Sea. These measurements have been compared to results obtained with the transport–chemistry model ACDEP which calculates the atmospheric inputs into the whole North Sea area. Finally, the results will be made available for the assessment of the impact of atmospheric nitrogen on coastal ecosystems. 相似文献
255.
建立潮汐汊道P-A关系的沉积动力学方法 总被引:6,自引:0,他引:6
在均衡状态下,潮汐汉道系统的纳潮量(P)与口门面积(A)之间存在着较稳定的关系,通常用幂函数形式来表达。计算P-A关系的传统O’Brien方法因其统计性质无法给出单一潮汐汉道的P-A关系。根据沉积动力学原理,每个潮汐汉道的P-A关系都受涨落潮历时、断面平均流速、口门形态、纳潮量、淡水径流量、沿岸毛输沙量和沉积物粒度等因素的控制,对上述因素的每一种组合,都有对应的均衡态P-A关系。作者在前人工作的基础上,尝试着建立了计算单一潮汐汊道P-A关系的沉积动力学方法,并以山东半岛月湖为算例对该方法的应用进行了讨论。结果表明,均衡态潮汐汉道的P-A关系的指数n稳定在1.15左右,而系统C的变化较大。 相似文献
256.
257.
Youngtak Ko Saro Lee Jonguk Kim Ki-Hyune Kim Mee-Sook Jung 《Ocean Science Journal》2006,41(3):149-161
The aims of this study are 1) to construct a database using geostatistics and Geographic Information System (GIS), and 2)
to derive the spatial relationships between manganese nodule abundance and other geological factors such as metal grade, slope,
water depth, topography, and acoustic characteristics of the sub-bottom. Using GIS, it is possible to analyze a large amount
of data efficiently, and to maximize the practical application, to increase specialization, and to enhance the accuracy of
the analyses. The greater the copper and nickel grade, the higher the rating. The distribution pattern of nickel grade is
similar to that of copper grade. The slopes are generally less than 3° except for seamounts and cliff areas. The rating shows
no correlation with slope. The rating is highest for slopes between 2.5 and 3.5° in block N1 and between 4.0 and 4.5° in block
N3. The topography is classified into five groups: seamount, hill crest, hill slant, hill base or plain, and seafloor basin
or valley. The rating proves lowest for seamount and hill crest. Our results show that the rating increases with the water
depth in the study area. Nodule abundance dose not show any significant relationship with the thickness of the upper transparent
layer in the study area. 相似文献
258.
Gerhard Kramm Hans Müller David Fowler Klaus D. Höfken Franz X. Meixner Eberhard Schaller 《Journal of Atmospheric Chemistry》1991,13(3):265-288
A modified profile method for determining the vertical deposition (or/and exhalation) fluxes of NO, NO2, ozone, and HNO3 in the atmospheric surface layer is presented. This method is based on the generally accepted micrometeorological ideas of the transfer of momentum, sensible heat and matter near the Earth's surface and the chemical reactions among these trace gases. The analysis (aerodynamic profile method) includes a detailed determination of the micrometeorological quantities (such as the friction velocity, the fluxes of sensible and latent heat, the roughness length and the zero plane displacement), and of the height-invariant fluxes of the composed chemically conservative trace gases with group concentrations c
1=[NO]+[NO2]+[HNO3], c
2=[NO2]+[O3]+3/2·[HNO3], and c
3=[NO]–[O3]–1/2·[HNO3]. The fluxes of the individual species are finally determined by the numerical solution of a system of coupled nonlinear ordinary differential equations for the concentrations of ozone and HNO3 (decoding method). The parameterization of the fluxes is based on the flux-gradient relationships in the turbulent region of the atmospheric surface layer. The model requires only the vertical profile data of wind velocity, temperature and humidity and concentrations of NO, NO2, ozone, and HNO3.The method has been applied to vertical profile data obtained at Jülich (September 1984) and collected in the BIATEX joint field experiment LOVENOX (Halvergate, U.K., September 1989). 相似文献
259.
伊利石结晶度及其在低温变质研究中若干问题的讨论 总被引:4,自引:0,他引:4
文中介绍与伊利石结晶度相关的伊利石矿物新的定名方案;讨论了伊利石结晶度的结晶学基础与Scherrer方程式的关系;讨论了三个重要的伊利石结晶度指数Weaver、K櫣bler和Weber指数的关系,并介绍推导的Weaver、K櫣bler和Weber指数的理论关系式;评价了衍射仪测量条件对结晶度数值的影响和三套伊利石结晶度标样的作用以及成岩带、变质带与葡萄石-绿纤石相、沸石相、绿纤石-阳起石亚相对比的依据。建议(1)停用绢云母一词;(2)建立可供各实验室使用的具有晶体结构和晶体化学参数和多型参数的伊利石结晶度标样;(3)建议多开展规范的可进行国际对比的低温变质研究,划分出与国际上一致的成岩带和近变质带,不仅利于低温变质作用理论的研究,而且由于成岩带到近变质转变带是重要的煤气油的生成带,也利于中国煤气油资源的勘探与开发,利于国民经济的长远持续发展。 相似文献
260.
空间方向关系形式化描述模型研究 总被引:12,自引:1,他引:12
空间方向关系形式化描述模型是空间关系研究的难点和重点,目前尚无完善的模型出现,因此进行其模型的研究意义重大。首先论述运用平面目标Voronoi图描述方向关系在理论上的可行性;然后详细阐述基于Voronoi图的空间方向关系形式化描述模型建立;为了验证模型的正确性,给出几个典型的算例;最后指出模型的优、缺点。 相似文献