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11.
The East Sea/Sea of Japan is a moderately productive sea that supports a wealth of living marine resources. Of the East Sea subregions, the southwest has the highest productivity. Various authors have proposed coastal upwelling, the Tsushima Current, the Changjiang Dilute Water, eddies, or discharge from the Nagdong River as potential sources of additional nutrients. In this paper, we propose, using satellite data from 1998 to 2006, that the biological productivity of the southwestern region is enhanced mainly by wind-driven upwelling along the Korean coast. Firstly, the climatology of seasonal patterns suggests that the enhanced chlorophyll a along the Korean coast is of local origin. Secondly, coastal upwelling is frequent in all seasons except winter. For example, along the coast of the Ulgi region, enhanced chlorophyll a due to coastal upwelling was observed for 25–92% of the time between Jun and Sep in the period 1998–2006. Thirdly, the advection of upwelled water through various pathways to the deeper basin was observed. Fourthly, there appeared to be a strong correlation between the interannual chlorophyll a variations of the coastal upwelling regions and the Ulleung Basin. The chlorophyll a patterns of both regions were closely related to the wind pattern in the upwelling regions, but not to that in the Ulleung Basin. Finally, changes in advection pathways also appeared to affect the productivity of the Ulleung Basin. Since 2004, there has been a shift in the pathways of upwelled water, and consequent increases in chlorophyll a in the Ulleung Basin were observed. This last observation requires further investigation. 相似文献
12.
Observations of the Fawn Trough Current over the Kerguelen Plateau from instrumented elephant seals 总被引:2,自引:1,他引:1
Fabien Roquet Young-Hyang Park Christophe Guinet Frdric Bailleul Jean-Benoît Charrassin 《Journal of Marine Systems》2009,78(3):377
Due to its great meridional extent and relatively shallow depths, the Kerguelen Plateau constitutes a major barrier to the eastward flowing Antarctic Circumpolar Current in the Indian sector of the Southern Ocean. While most of the Antarctic Circumpolar Current transport is deflected north of the Kerguelen Islands, the remainder ( 50 Sv, 1 Sv = 106 m3 s− 1) must pass south of the islands, most probably through the Fawn and Princess Elizabeth Troughs. However, the paucity of finely resolved quasi-synoptic hydrographic data in this remote and infrequently sampled area has limited the progress in our knowledge of the regional circulation. Since 2004, a new approach using elephant seals from the Kerguelen Islands as autonomous oceanographic profilers has provided new information on the hydrography over the Kerguelen Plateau, covering the entire Antarctic Zone between the Polar Front and Antarctica, with a mean along-track resolution of about 25 km. These finely resolved bio-logged data revealed details of a strong northeastward current found across the Fawn Trough (sill depth: 2600 m; 56°S, 78°E). This so-called Fawn Trough Current transports cold Antarctic waters found mostly south of the Elan Bank, between the Ice Limit (58°S) and the Antarctic Divergence (64°S) in the eastern Enderby Basin, toward the Australian–Antarctic Basin. Our analysis also demonstrates that the Deep Western Boundary Current, which carries cold Antarctic water along the eastern flank of the southern Kerguelen Plateau collides with Fawn Trough Current at the outlet of the Fawn Trough sill. In other words, the Fawn Trough constitutes a veritable bottleneck, channelling the quasi-totality of the Antarctic Circumpolar flow found south of the Polar Front. Thanks to the unprecedented fine resolution of seal-borne data, a branch of flow centered at the Winter Water isotherm of 1 °C is also revealed along the northern escarpment of the Elan Bank, and then along the southern edge of Heard Island. Further analysis of different supplementary data reveals a complex circulation pattern in the entire Enderby Basin, with several distinctive branches of flow being strongly controlled by prominent topographic features such as the Southwest Indian Ridge, Conrad Rise, Elan Bank, and Kerguelen Plateau. This newly emerged frontal structure refines considerably previous large-scale circulation schematics of the area. 相似文献
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GLENN LYONS 《运输评论》2013,33(4):485-509
In 1963, the Buchanan Report in the UK advocated a combination of new road capacity, improved public transport and traffic restraint as a means to tackle congestion. Forty years on, and the advice from many transport experts remains the same. However, the scale and complexity of the problems associated with a mobility‐dependent society have grown. The need for politicians to make tough but realistic policy decisions on transport is now becoming unavoidable. They must confront the realities of living with the car as must the general public. Policymakers now also have social well‐being and sustainable development moving higher on their agendas alongside transport. Against such a backdrop, the paper makes the case for transport research, policy and practice to acknowledge more fully the inherent links between transport and society. It argues that greater recognition and understanding of such links is crucial to confronting the present realities. Transport does not merely serve society: it shapes society, as in turn society shapes transport. The future of each is dependent on the other, and this fact must be recognized. The paper advocates in turn that the transport profession must move from its heartlands in engineering and economics also to embrace more fully such disciplines as sociology and psychology. A factual picture of the many facets of present‐day society is presented and the implications for travel demand are discussed. Through considering phenomena such as social norms and habitual behaviour, it is then argued that the travel choices and behaviour of individuals are not simply a matter of economic optimization. This points to the need for decision‐makers to be furnished with better evidence about the transport problems faced and the potential efficacy of measures that might be taken. Discussion of public attitudes and the role of the media are included in the context of assessing how politicians can be encouraged and supported in their implementation of realistic but unpopular policies. Evidence and experience within the paper are UK based, although many of the issues and arguments apply world wide. 相似文献
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铁路设计院在勘察设计过程中产生的科技档案是铁路工程建设的重要资料和宝贵财富,是下一步施工、监理等建设环节的重要依据。只有不断地加强铁路设计院的纸质文件和电子文件的收集、整理和归档工作,才能保证铁路科技档案完整、准确、系统、安全和有效利用,更好地为铁路建设服务。本文对铁路勘察设计院科学技术档案纸质文件、电子文件归档过程中存在的一些问题以及解决方法进行论述。 相似文献
17.
江苏2008高考新方案从出台到审核,都引起空前的争议,褒扬和贬斥之声都有,江苏高考的改革也再次引起人们的关注,这不由让人想起四年前江苏的"3 2"高考制度改革。作为该制度的第一届被选拔者,同时作为该制度第一届本科毕业生,本文结合自身对高考制度的理解,结合大学对中学人才培养的要求,结合高考的公平性原则等,分析了"3 2"制度本身存在的一些问题。 相似文献
18.
This paper presents a global ocean implementation of a multi-component model of marine pelagic biogeochemistry coupled on-line with an ocean general circulation model forced with climatological surface fields (PELAgic biogeochemistry for Global Ocean Simulations, PELAGOS). The final objective is the inclusion of this model as a component in an Earth System model for climate studies. The pelagic model is based on a functional stoichiometric representation of marine biogeochemical cycles and allows simulating the dynamics of C, N, P, Si, O and Fe taking into account the variation of their elemental ratios in the functional groups. The model also includes a parameterization of variable chlorophyll/carbon ratio in phytoplankton, carrying chl as a prognostic variable. The first part of the paper analyzes the contribution of non-local advective–diffusive terms and local vertical processes to the simulated chl distributions. The comparison of the three experiments shows that the mean chl distribution at higher latitudes is largely determined by mixing processes, while vertical advection controls the distribution in the equatorial upwelling regions. Horizontal advective and diffusive processes are necessary mechanisms for the shape of chl distribution in the sub-tropical Pacific. In the second part, the results have been compared with existing datasets of satellite-derived chlorophyll, surface nutrients, estimates of phytoplankton community composition and primary production data. The agreement is reasonable both in terms of the spatial distribution of annual means and of the seasonal variability in different dynamical oceanographic regions. Results indicate that some of the model biases in chl and surface nutrients distributions can be related to deficiencies in the simulation of physical processes such as advection and mixing. Other discrepancies are attributed to inadequate parameterizations of phytoplankton functional groups. The model has skill in reproducing the overall distribution of large and small phytoplankton but tends to underestimate diatoms in the northern higher latitudes and overestimate nanophytoplankton with respect to picoautotrophs in oligotrophic regions. The performance of the model is discussed in the context of its use in climate studies and an approach for improving the parameterization of functional groups in deterministic models is outlined. 相似文献
19.
从城市环境的现状和影响城市环境的因素入手,对城市景观设计中应具备的生态观和审美观进行分析,根据分析的结果,提出一套适合城市发展需要景观设计的新思路、新理念。 相似文献
20.
自古以来,人类探索海洋,向往海洋与回归海洋的航海实践活动生生不息,从不间断。人类在这一伟大征程中所体现的不畏艰险,勇于探索的无数壮举与崇高精神永远值得思考与总结。人类在驾驭和征服海洋过程中所折射出的认知创新、技术创新与文化交融的创新硕果,将激励我们在可持续利用人类第二大生存空间———海洋与建设海洋强国的征程中,继续发扬伟大的郑和精神,不断创新航海技术,重铸我国航海事业的辉煌。 相似文献