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51.
Dissolved titanium distributions in the Mid-Atlantic Bight 总被引:1,自引:0,他引:1
Although titanium is abundant in Earth's crust, its sources and distribution in the ocean are poorly understood. To elucidate its behavior, distributions of dissolved (< 0.2 μm) Ti were determined in surface waters and vertical profiles from the Mid-Atlantic Bight (MAB). Concentrations of Ti decreased from 390 pM at the Delaware Bay mouth to < 100 pM across the Delaware continental shelf. In vertical profiles, small increases in bottom waters suggest a possible flux of Ti from shelf sediments, consistent with previous reports of pore water enrichments of dissolved Ti in MAB sediments. Concentrations in surface waters of the outer shelf and slope ranged between 30 and 140 pM, with most values below 90 pM. Concentrations in a 1000 m vertical profile in the eastern Gulf Stream ranged between 110 and 280 pM, and showed a variable distribution attributed to the mixing of water masses in the outer MAB. A simple model of Ti sources to the MAB suggests that atmospheric deposition of dissolved Ti is comparable to net riverine contributions and therefore must be considered in applications of Ti as a tracer of oceanographic processes. 相似文献
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The solubility of iron, aluminium, manganese and phosphorus has been determined in aerosol samples collected between 49°N and 52°S during three cruises conducted in the Atlantic Ocean as part of the European Union funded IRONAGES programme. Solubilities (defined at pH 4.7) determined for Fe and Al in samples of Saharan dust were significantly lower (medians 1.7% and 3.0%, respectively) than the solubilities of these metals in aerosols from other source regions (whole dataset medians 5.2% and 9.0%, respectively). Mn solubility also varied with aerosol source, but the median solubility of Mn in Saharan dust was very similar to the median for the dataset as a whole (55% and 56%, respectively). The observed solubility of aerosol P was ∼ 32%, with P solubility in Saharan aerosol perhaps as low as 10%. Laboratory studies have indicated that aerosol Fe solubility is enhanced by acid processing. No relationship could be found between Fe solubility and the concentrations of acid species (non-seasalt SO42−, NO3−) nor the net acidity of the aerosol, so we are unable to confirm that this process is significant in the atmosphere. In terms of the supply of soluble Fe to oceanic ecosystems on a global scale, the observed higher solubility for Fe in non-Saharan aerosols is probably not significant because the Sahara is easily the dominant source of Fe to the Atlantic. On a smaller scale however, higher solubility for aerosol Fe may alter our understanding of Fe cycling in regions such as the remote Southern Ocean. 相似文献
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阿根廷滑柔鱼渔场的初步研究 总被引:2,自引:0,他引:2
根据2001年12月至2002年4月"辽渔1号"在西南大西洋(57°W—60°W,41°S—47°S)的柔鱼生产调查资料,对作业渔场的渔获量和水温垂直分布特点进行了初步分析,并运用逐步回归法探讨了周产量(t/week)与各水层温度之间的关系。结果表明:(1)周产量在70t以上的作业区域全部在60°02′W—60°40′W,44°59′S—46°04′S范围内(简称南渔场),周产量在70t以下的作业区域绝大多数集中在57°47′W—58°2′W,41°54′S—42°2′S范围内(简称北渔场);(2)南渔场渔获的表层水温在12.2℃~15.1℃,北渔场渔获的表层水温在10.0℃~12.3℃,两渔场在20~70m水体均出现了强度不等的温跃层;(3)整个作业区域,周产量与水温存在线性相关,相关系数R=0.8515,其中南渔场相关系数R=0.9985,北渔场相关系数R=0.9313。 相似文献
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根据海洋调查历史资料 ,对台湾东北海域冷水块的时空分布、结构、特点进行分析 ,主要结果如下 :(1 )首次利用卫星跟踪漂流浮标的轨迹 ,佐证冬季该冷水块的存在。 (2 )鉴于该冷水的重要性 ,建议对它给予称谓 ,暂定名为“彭花棉”冷水块。 (3 )该冷水块是黑潮次表层水涌升的结果 ,是黑潮对我国近海海洋环境影响的典型实例之一。 (4)该冷水块具有低温、高盐、高密、低氧、高磷、高硅和高氮等特性 相似文献
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V. Carmillet J. -M. Brankart P. Brasseur H. Drange G. Evensen J. Verron 《Ocean Modelling》2001,3(3-4)
Within the European DIADEM project, a data assimilation system for coupled ocean circulation and marine ecosystem models has been implemented for the North Atlantic and the Nordic Seas. One objective of this project is to demonstrate the relevance of sophisticated methods to assimilate satellite data such as altimetry, surface temperature and ocean color, into realistic ocean models. In this paper, the singular evolutive extended Kalman (SEEK) filter, which is an advanced assimilation scheme where three-dimensional, multivariate error statistics are taken into account, is used to assimilate ocean color data into the biological component of the coupled system. The marine ecosystem model, derived from the FDM model [J. Mar. Res. 48 (1990) 591], includes 11 nitrogen and carbon compartments and describes the synthesis of organic matter in the euphotic zone, its consumption by animals of upper trophic levels, and the recycling of detritic material in the deep ocean. The circulation model coupled to the ecosystem is the Miami isopycnic coordinate ocean model (MICOM), which covers the Atlantic and the Arctic Oceans with an enhanced resolution in the North Atlantic basin. The model is forced with realistic ECMWF ocean/atmosphere fluxes, which permits to resolve the seasonal variability of the circulation and mixed layer properties. In the twin assimimation experiments reported here, the predictions of the coupled model are corrected every 10 days using pseudo-measurements of surface phytoplankton as a substitute to chlorophyll concentrations measured from space. The diagnostics of these experiments indicate that the assimilation is feasible with a reduced-order Kalman filter of small rank (of order 10) as long as a sufficiently good identification of the error structure is available. In addition, the control of non-observed quantities such as zooplankton and nitrate concentrations is made possible, owing to the multivariate nature of the analysis scheme. However, a too severe truncation of the error sub-space downgrades the propagation of surface information below the mixed layer. The reduction of the actual state vector to the surface layers is therefore investigated to improve the estimation process in the perspective of sea-viewing wide field-of-view sensor (SeaWiFS) data assimilation experiments. 相似文献
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