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101.
This paper brings together unpublished historical data sets and published literature to review the role of climatic, oceanographic and ecological processes in the marine ecosystem of the eastern Canadian Archipelago. Physical data include characteristics of the water masses, circulation patterns, sea ice conditions, and climatic records from 1950s onward. Biological data include unpublished data sets on nutrients, primary and secondary production, and sedimentation, which were collected during the 1980–1990s in the eastern Canadian Archipelago. These results show high year-to-year variability in nutrient inventories and ratios, the magnitude of the ice algae and phytoplankton bloom, the timing of ice algae sedimentation in the spring, and the composition of the zooplankton community. The significance of this high interannual variability and its effect on pelagic–benthic coupling processes is discussed in the context of climatic and oceanographic forcing, with emphasis on recent (past decade) Arctic changes. An estimate of total primary production in the Archipelago is also presented, along with published production estimates for other Arctic shelves, showing that the Archipelago may support up to 32% of the total primary production of Arctic shelves. The high year-to-year variability in production and carbon transfer pathways (e.g. pelagic versus benthic) in the Archipelago suggest that the system might be resilient to the increased variability in climatic conditions occurring in the past decade. However, this increased variability combined with directional change in climatic and oceanographic conditions might also modify the existing balance of ecological processes. For example, shifts in the timing of events appear to have already occurred in the past decade, with potential cascading effects throughout the ecosystem. 相似文献
102.
渤海、北黄海海冰与气候变化的关系 总被引:13,自引:7,他引:13
渤海和北黄海的冰情随着历年冬季气候差异而不同.暖冬海冰覆盖范围不足海域的15%,而寒冬可覆盖海域80%以上.概述了海冰监测及资料来源.冰覆盖面积、外缘线位置和冰况等级等被作为反映结冰海域冰情的指标.用大连和营口站的气温表示渤海、北黄海海域的局地气候.用1952~2000年大连的月平均气温描述冰情的变化.给出冰情指数由1952/1953年到1999/2000年随大连站月平均气温变化.影响渤海和北黄海冰情和气候的因子很多,诸如大气环流的演变和太阳活动等.分析了多种因子与冰情的滞后相关,指出20世纪90年代渤海冰情持续偏轻与全球气候变暖趋势相当一致;渤海和北黄海冰情的年际变化与El-Nino现象以及太阳活动周期有关;讨论了海冰季节演变的特征 相似文献
103.
The HY-1A satellite is the first oceanic satellite of China. During the winter of 2002~2003, the data of the HY-1A were applied to the sea ice monitoring and forecasting for the Bohai Sea of China for the first time. The sea ice retrieval system of the HY-1A has been constructed. It receives 1B data from the satellite, outputs sea ice images and provides digital products of ice concentration, ice thickness and ice edge, which can be used as important information for sea ice monitoring and the initial fields of the numeric sea ice forecast and as one of the reference data for the sea ice forecasting verification. The sea ice retrieval system of the satellite is described, including its processes, methods and parameters. The retrieving results and their application to the sea ice monitoring and forecasting for the Bohai Sea are also discussed. 相似文献
104.
AnomalouschangeoftheAntarcticseaiceandglobalsealevelchange¥XieSimei;ZouBing;WangYiandBaoChenglan(1.NationalMarineEnvironmentF... 相似文献
105.
106.
On the recent warming of the southeastern Bering Sea shelf 总被引:1,自引:0,他引:1
P.J. Stabeno N.A. Bond S.A. Salo 《Deep Sea Research Part II: Topical Studies in Oceanography》2007,54(23-26):2599
During the last decade, the southeastern Bering Sea shelf has undergone a warming of 3 °C that is closely associated with a marked decrease of sea ice over the area. This shift in the physical environment of the shelf can be attributed to a combination of mechanisms, including the presence over the eastern Bering Sea shelf of a relatively mild air mass during the winter, especially from 2000 to 2005; a shorter ice season caused by a later fall transition and/or an earlier spring transition; increased flow through Unimak Pass during winter, which introduces warm Gulf of Alaska water onto the southeastern shelf; and the feedback mechanism whereby warmer ocean temperatures during the summer delay the southward advection of sea ice during winter. While the relative importance of these four mechanisms is difficult to quantify, it is evident that for sea ice to form, cold arctic winds must cool the water column. Sea ice is then formed in the polynyas during periods of cold north winds, and this ice is advected southward over the eastern shelf. The other three mechanisms can modify ice formation and melt, and hence its extent. In combination, these four mechanisms have served to temporally and spatially limit ice during the 5-year period (2001–2005). Warming of the eastern Bering Sea shelf could have profound influences on the ecosystem of the Bering Sea—from modification of the timing of the spring phytoplankton bloom to the northward advance of subarctic species and the northward retreat of arctic species. 相似文献
107.
Donald L. Forbes George S. Parkes Gavin K. Manson Lorne A. Ketch 《Marine Geology》2004,210(1-4):169-204
Storms play a major role in shoreline recession on transgressive coasts. In the southern Gulf of St. Lawrence (GSL), southeastern Canada, long-term relative sea-level rise off the North Shore of Prince Edward Island has averaged 0.3 m/century over the past 6000 years (>0.2 m/century over 2000 years). This has driven long-term coastal retreat at mean rates >0.5 m/a but the variance and details of coastal profile response remain poorly understood. Despite extensive sandy shores, sediment supply is limited and sand is transferred landward into multidecadal to century-scale storage in coastal dunes, barrier washover deposits, and flood-tidal delta sinks. Charlottetown tide-gauge records show mean relative sea-level rise of 3.2 mm/a (0.32 m/century) since 1911. A further rise of 0.7±0.4 m is projected over the next 100 years. When differenced from tidal predictions, the water-level data provide a 90-year record of storm-surge occurrence. Combined with wind, wave hindcast, and sea-ice data, this provides a catalogue of potentially significant coastal storms. We also document coastal impacts from three recent storms of great severity in January and October 2000 and November 2001. Digital photogrammetry (1935–1990) and shore-zone surveys (1989–2001) show large spatial and temporal variance in coastal recession rates, weakly correlated with the storm record, in part because of wave suppression or coastal protection by sea ice. Large storms cause rapid erosion from which recovery depends in part on local sand supply, but barrier volume may be conserved by washover deposition. Barrier shores with dunes show high longshore and interdecadal variance, with extensive multidecadal healing of former inlet and overwash gaps. This reflects recovery from an episode of widespread overwash prior to 1935, possibly initiated by intense storms or groups of storms in the latter half of the 19th century. With evidence from the storms of 2000–2001, this points to the importance of storm clustering on scales of weeks to years in determining erosion vulnerability, as well as the need for a long-term, large-scale perspective in assessing coastal stability. The expected acceleration in relative sea-level rise, together with projections of increasing storm intensity and greatly diminished winter ice cover in the southern GSL, implies a significant increase in coastal erosion hazards in future. 相似文献
108.
北极气候系统正在发生显著变化,其中,海冰面积和厚度的减小是其最主要的特征.楚科奇海是海冰面积变化最有代表性的区域.文章利用积累了9a的高分辨率海冰分布数据研究海冰面积的多年变化特征.结果表明,各年的冰情有显著的季节内变化,海冰面积距平曲线体现了不同时期海冰面积变化的动态过程.在1997~2005年间,楚科奇海海冰面积经历了轻(1997年)-重(2000~2001年)-轻(2002~2005年)的变化过程.9a的数据总体上体现了海冰面积减小的趋势,2005年的冰情呈现了历史新低.每年融冰期的长短与冰情轻重有密切的关系,冰轻年份融冰开始时间早,冻结结束时间晚.各年海冰面积最小值发生在9月下旬至10月初,各个年份海冰最小面积差别很大.有的年份只有4%,而重冰年可以大于50%.文章采用4个重要参数表达海冰多年变化.其中海冰面积指数反映了当年总体平均的海冰面积距平;海冰最小面积反映了融冰期海冰的极限情况;上一个冬季的气温积温也与翌年海冰面积有良好的关联;分析了风场对海冰的影响,表明风场在融冰期能够在短时间内改变海冰的覆盖面积. 相似文献
109.
本文是根据南极“八五”国家攻关课题中的“南极海冰监测和预报”的考核目标,实现为南极考察船在 冰区中航行提供精确和清晰的冰图和预报。 相似文献
110.