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11.
Marta Marcos Guy Wppelmann Wolfgang Bosch Roman Savcenko 《Journal of Marine Systems》2007,68(3-4):529-536
Sea level time series derived from TOPEX altimeter and from tide gauge measurements in the Bay of Biscay (Eastern North Atlantic Ocean) are used to investigate the regional sea level rise. Altimetry sea level anomalies are computed from TOPEX measurements and resampled into fixed along track bins in order to obtain consistent records and to approach as close as possible to the coast. Tidal corrections are critical in the estimation of sea level trends; therefore an additional analysis has been carried out in order to identify and correct for residual tidal signals. The obtained mean sea level rise in the region is + 3.09 ± 0.21 mm/year over the period 1993–2002. Tide gauges have been corrected for vertical land motions by means of collocated GPS measurements. GPS-corrected tide gauges and nearby altimetry trends are found to be statistically consistent. The relationship with the atmospheric forcing is also investigated revealing that 15% of this sea level rise is attributed to the atmospheric pressure effects. 相似文献
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Emmanuel Guy 《Maritime Policy and Management》2003,30(3):231-242
One recent transformation of liner shipping is the entry of leading carriers into north-south markets. This paper aims to test the commonly held proposition that global shipping lines entered north-south markets to feed more cargo on their established east-west services. This proposition arises out of: (1) predominant models of transport networks evolution which emphasize the influence of hubs, and (2) lines' strategy of commissioning larger vessels for east-west routes. In this perspective, the expansion of networks to southern economies serves specifically to bring more cargo on main routes to ensure volumes are sufficient to generate the desired economies of scale. This paper analyses the changing configurations of South American services. Results show that by 1999 leading shipping lines were offering direct services to all major trade ranges from the region, and numerous US loops were added to the already established European and Asian services. These new services involved multiple ports in the US; running in parallel with east-west services over a large part of the American coasts. The paper concludes that global shipping lines entered the South American market by setting up services typically configured to serve trades between North and South America; not to feed established main routes. 相似文献
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Fredrick Ekow Jonah Emmanuel Abeashi Mensah Regina Esi Edziyie Nelson Winston Agbo 《Coastal management》2016,44(2):116-130
Coastal erosion is a serious problem that affects the safety and livelihoods of many coastal dwellers along Ghana's coast. Despite the fact that coastal erosion is a natural phenomenon, erosion trends have been largely aggravated by human-induced factors. This study analyzed shoreline change rates for three neighbouring coastal communities in the Central region of Ghana; Elmina, Cape Coast and Moree. Two epochs were analyzed, 1974–2012 (medium-term) and 2005–2012 (short-term), using ArcGIS and Digital Shoreline Analysis System. Overall, the entire study area recorded average shoreline change rates of ?1.24 myear?1 and ?0.85 myear?1 in the medium-term and short-term period respectively. Less consolidated shoreline segments recorded higher erosion rates in both periods while cliffs and rocky segments experienced very little erosion or high stability. Because shorelines undergoing chronic erosion do not fully recover after short-term erosion events such as storms, facilities located close to such shorelines are threatened. Taking a proactive approach to coastal erosion management, such as coastal sand mining prevention, inter-sectoral land use management and adopting a construction setback approach may be prudent for the long-term management of the coast since this recognizes future shoreline changes and safeguards coastal landscape for other uses. 相似文献
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Philippe Koubbi Guy Duhamel Jean-Henri Hecq Cristina Beans Christophe Loots Patrice Pruvost Eric Tavernier Marino Vacchi Carole Vallet 《Journal of Marine Systems》2009,78(4):547
Since the article published by Loeb et al. [Loeb, V.J., Kellermann, A., Koubbi, P., North, A.W., White, M., 1993. Antarctic larval fish assemblages: a review. Bull. Mar. Sci. 53(2), 416–449.] about Antarctic ichthyoplankton, many surveys were carried out in different sectors of the Southern Ocean focusing on different aspects of the ecology of fish larvae. Some of these researches were conducted in the Subantarctic Kerguelen Islands and others on the continental shelf off Terre Adélie and Georges V land. Oceanographic and geographic features influence fish larvae ecology such as island mass effects, gyres, canyons. Antarctic fishes show also temporal segregation of spawning which induces temporal succession of early stage larvae. This avoids competition and probably the predation on early stages for species having few recruits. In that case, we have to understand how these larvae can deal with the match–mismatch with their preys and how they find sufficient food to survive. But our knowledge on Antarctic fish larvae is still insufficient as we do not know larvae for quite a lot of species and because of the difficulty to sample during winter. 相似文献
15.
Guy Cohen Jean-Pierre Quadrat Laura Wynter 《Transportation Research Part B: Methodological》2002,36(10)
In Clegg and Smith [Transportation Research B 35 (2001) 71–82] and Battye et al. [in: M. Patriksson, M. Labbe (Eds.), Transportation Planning – State of the Art, Proceedings of the 6th Meeting of the EURO Working Group on Transportation, Gothenburg, Sweden, September 9–11, 1998, Kluwer Academic Publishers, Dordrecht], Smith and colleagues present an algorithm for solving the bilevel programming problem. We show that the points reached by the algorithm are not stationary points of bilevel programs in general. We further show that, with a minor modification, this method can be expressed as an inexact penalty method for gap function-constrained bilevel programs. 相似文献
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