共查询到20条相似文献，搜索用时 15 毫秒
1.
《Deep Sea Research Part II: Topical Studies in Oceanography》1999,46(8-9):1577-1595
This paper provides an overview of dust transport pathways and concentrations over the Arabian Sea during 1995. Results indicate that the transport and input of dust to the region is complex, being affected by both temporally and spatially important processes. Highest values of dust were found off the Omani coast and in the entrance to the Gulf of Oman. Dust levels were generally lower in summer than the other seasons, although still relatively high compared to other oceanic regions. The Findlater jet, rather than acting as a source of dust from Africa, appears to block the direct transport of dust to the open Arabian Sea from desert dust source regions in the Middle East and Iran/Pakistan. Dust transport aloft, above the jet, rather than at the surface, may be more important during summer. In an opposite pattern to dust, sea salt levels were exceedingly high during the summer monsoon, presumably due to the sustained strong surface winds. The high sea salt aerosols during the summer months may be impacting on the strong aerosol reflectance and absorbance signals over the Arabian Sea that are detected by satellite each year. 相似文献
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3.
The aim of this study is to elucidate the seasonal variation in the volume transport through the Tsushima-Korea Strait using the sea level difference across the Strait. The sea level difference associated with the baroclinic motion is estimated from the geostrophic current profile, which is calculated as its vertical integrated transport is zero, using the CTD data from 1988 to 1990. The sea level difference associated with the barotropic motion is estimated by subtracting the sea level difference associated with the baroclinic motion from the observed one. The range (maximum-minimum) of the seasonal variation in the volume transport is evaluated about 0.7 Sv on the average, using the sea level difference associated with the barotropic motion. It is one third of the seasonal variation in the volume transport which is estimated from observed sea level difference on the assumption that no baroclinic component exists. Such analyses also indicate that the volume transport was at a maximum in early winter and at a minimum in early spring from 1988 to 1990. The negative correlation is also found between the volume transport through the eastern channel and that through the western channel. Moreover, it is noticed that the seasonal variation in the surface current velocity in the Strait largely contains baroclinic motions which are locally caused in the Tsushima-Korea Strait. 相似文献
4.
R. García L. Thomsen H.C. de Stigter E. Epping K. Soetaert E. Koning P.A. de Jesus Mendes 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(8):1012-1026
The role of the Setúbal–Lisbon canyon in accumulation and transport of labile organic matter from the coastal sea and ocean surface water towards the deep sea was assessed by investigating the distribution of organic matter of different quality in sedimentary aggregates and surface sediments of the canyon and adjacent slopes. Total hydrolysable amino acids (THAA) and organic carbon (Corg) were measured from aggregates, and contents of Corg, chlorophyll a (chl a), phaeopigments (phaeo), chloroplastic pigment equivalents (CPE) from sediments. As indices of organic matter (OM) quality THAA:Corg, degradation index (DI), chl a:phaeo, chl a:Corg and C:N ratio were determined. Sediment profiles of chl a and the isotope 210 of lead (210Pb) were used as tracers in a transport model to estimate deposition rates and background levels of the tracers, and sediment mixing rates (Db). Whereas bulk Corg contents of canyon and slope sediments were practically similar at all depths, higher contents of THAA, chl a and CPE, as well as higher THAA:Corg, DI and chl a:Corg, in aggregates and sediments from the upper reaches of the canyon indicate that labile organic matter accumulates in the upper canyon. This is confirmed by higher chl a and 210Pb deposition and Db calculated from the model. Hence, the Setúbal–Lisbon canyon, specially the upper region, acts as a natural trap of organic matter that is transported to the region via lateral transport and vertical settling from primary productivity. Organic matter might be further transported in downward canyon direction via rebound processes. The chl a and 210Pb profiles reveal active sediment mixing by physical processes and/or animal reworking. 相似文献
5.
M. Pirrung C. Hillenbrand B. Diekmann D. Fütterer H. Grobe G. Kuhn 《Geo-Marine Letters》2002,22(3):170-180
Spatial distribution of magnetic susceptibility and the gravel fraction in surface sediments in the Atlantic sector of the Southern Ocean were investigated to reconstruct source areas and recent transport pathways of magnetominerals and ice-rafted debris. Maxima of magnetic susceptibility were observed offshore from areas where mafic source rocks occur, e.g. Queen Maud Land and the northern Antarctic Peninsula. The glacigenic input of debris and subsequent redeposition of fine material by bottom and turbidity currents on the continental margins result in regional variations of the gravel and susceptibility values. In the deep sea, however, the mixing of ice-rafted debris and turbidites from distal source areas causes a homogenous distribution of the susceptibility signal. On submarine elevations such as Maud Rise and Astrid Ridge, dust input may be an additional source for magnetominerals. 相似文献
6.
我国沙尘暴与赤潮的相关性研究 总被引：2，自引：0，他引：2
总结了近十几年来我国北方沙尘暴和近海赤潮的危害和发生趋势 ,并对两者间的相关性做了初步分析。结果显示 :我国东海和南海赤潮的发生受沙尘暴的影响很小 ,而黄海和渤海赤潮的发生与北方的沙尘暴有一定的相关性。要正确估价沙尘暴对海洋生态系 (包括赤潮 )的影响 ,必须对沙尘暴的迁移规律、入海通量以及沙尘暴粒子在海洋中的物化反应做详细的调查和研究。 相似文献
7.
为了揭示南极海冰年际变化的机制,利用南极海冰边缘区密集度和海面风资料,选择南极海冰边缘区海冰密集度年际变化较大的5个海区进行统计分析.研究表明：南半球冬季在这5个海区海冰密集度年际变化与南侧西风的年际变化有较密切的关系,南半球冬季南极海冰边缘区南侧西风形成向北的Ekman输运对海冰边缘区的海冰密集度有重要的影响,这种影响在南太平洋和南大西洋比在南印度洋东部更明显. 相似文献
8.
Fluctuation in volume transport distribution accompanied by the Kuroshio front migration in the Tokara Strait 总被引：1，自引：0，他引：1
A relation between migration of the Kuroshio front and fluctuation of distribution of volume transport in the Tokara Strait was described, using sea level records at five tide gauge stations around the strait and data which were composed of sea surface temperature, XBT casts, sea surface salinity and velocities at 20 m, 75 m and 150 m depths taken en route a ferryboat. The Kuroshio front extends to about 150 m depth. The sea surface salinity and the horizontal velocities abruptly change at the front. There is a good correlation in a period range from half a month to two months between the migration of the front, which is not only at the surface but also in the subsurface, and the sea level fluctuation at Nakano-shima. A northward migration of the front with a period range from 17 to 50 days decreases the transport in the southern strait between Naze and Nakano-shima but increases in the northern strait between Nakano-shima and Sata-misaki. The northward migration intensifies inflow into Kagoshima Bay and the Ohsumi Branch Current. Correlation between the transport in the northern strait and the Ohsumi Branch Current is significant in the period range from 30 to 50 days. In this significant period range, the former leads the latter by about 3 days. 相似文献
9.
Mitsuo Uematsu 《Journal of Oceanography》1987,43(6):395-401
I am deeply honored to have been selected as a recipient of the 1987 Okada Prize by the Oceanographical Society of Japan. The present paper reviews my work and recent studies of other investigators concerning mineral aerosol (dust) particles in the marine atmosphere over the Pacific Ocean. I would like to emphasize the importance of atmospheric deposition of continental substances to the ocean environment. From consecutive measurements of atmospheric dust concentrations and total deposition fluxes at 13 island stations in the Pacific Ocean, a strong seasonal transfort pattern of dust particles was found at most of the stations. High atmospheric dust concentrations occurred during the spring in both hemispheres. There was a latitudinal gradient in both the atmospheric dust concentration and flux, with the highest values observed at midlatitudes. When combined with observations of dust storms in Asia and isentropic trajectory analysis, it was clear that the dust over the central North Pacific was transported by the upper westerly winds from the arid desert regions in central and eastern Asia. Transport times were 1–2 weeks, and in some cases, atmospheric transport paths of over 10,000 km were observed. Infrequent short-term dust events contributed most of annual atmospheric dust flux to the open ocean. These sporadic inputs are major sources for both suspended mineral matter in the water column and the non-biogenic component of deep-sea sediments in the Pacific Ocean. The impact of atmospheric dust fluxes on chemical and biological processes in the water column remains to be determined. 相似文献
10.
文章以假设发生在南海北部深水油气勘探开发海域的1279m深水井喷溢油事故为例,采用深海溢油输移扩散模型,以2020年冬季（1月）和夏季（7月）三维流场和海面风场为主要环境动力,数值模拟研究未实施和实施海底消油剂处理情景下的溢油在海洋环境中的输移扩散全过程。模拟结果显示:不同深度的海流对溢油输移轨迹有着显著的影响;深水环... 相似文献
11.
Variability of Sea Surface Circulation in the Japan Sea 总被引：3，自引：0，他引：3
Composite sea surface dynamic heights (CSSDH) are calculated from both sea surface dynamic heights that are derived from altimetric data of ERS-2 and mean sea surface that is calculated by a numerical model. The CSSDH are consistent with sea surface temperature obtained by satellite and observed water temperature. Assuming the geostrophic balance, sea surface current velocities are calculated. It is found that temporal and spatial variations of sea surface circulation are considerably strong. In order to examine the characteristics of temporal and spatial variation of current pattern, EOF analysis is carried out with use of the CSSDH for 3.5 years. The spatial and temporal variations of mode 1 indicate the strength or weakness of sea surface circulation over the entire Japan Sea associated with seasonal variation of volume transport through the Tsushima Strait. The spatial and temporal variations of mode 2 mostly indicate the temporal variation of the second branch of the Tsushima Warm Current and the East Korean Warm Current. It is suggested that this variation is possibly associated with the seasonal variation of volume transport through the west channel of the Tsushima Strait. Variations of mode 3 indicate the interannual variability in the Yamato Basin. 相似文献
12.
中国东部海域大气气溶胶入海通量的研究 总被引：18，自引：2，他引：16
根据中国东部海域气溶胶浓度及分级采样资料,计算得出黄海、东海及日本以南海域沙尘气溶胶的代表元素铝(Al)每月干沉降通量分别为42.8、18.3、5.2mg/m2;其中各海域春季的干沉降通量均占全年干沉降通量的40%以上.相应每月总沉降通量分别为54.1、29.8、10.5mg/m2.渤海、黄海、东海及日本以南海域每年沙尘气溶胶总沉降通量分别为26.4、9.3、5.1、1.8g/m2.东海污染元素总沉降通量以春季最大,夏、秋季次之,冬季最小.日本以南海域锑(Sb)元素总沉降通量的季节分布为冬季最大,夏、秋季次之,秋季最小;硒(Se)元素总沉降通量的最大值出现在夏季,其他季节分布比较均匀. 相似文献
13.
Abraham Golik 《Geo-Marine Letters》1993,13(3):159-164
The geographical distribution of coal particles that fell during nine years to the sea bottom from the open sea coal terminal off Hadera, Israel, shows a consistent northerly transport path, and it is inconceivable that the sand at that location would move in an opposite direction. Semicircular, current-scoured moats associated with small mounds found at the edge of the continental shelf off Ashdod and Haifa, Israel, also suggest a general northward-directed sediment transport. The northward sediment flow on the Israeli continental shelf inferred from this evidence therefore supports the model of Emery and Neev about general sand transport patterns along the Israeli coastline and continental shelf. 相似文献
14.
A mesocosm experiment coupled with optical measurements to assess the fate and sinking of atmospheric particles in clear oligotrophic waters 总被引：1，自引：1，他引：0
Matthieu Bressac Cécile Guieu David Doxaran Fran?ois Bourrin Grigor Obolensky Jean-Michel Grisoni 《Geo-Marine Letters》2012,32(2):153-164
It has recently been postulated that lithogenic particles such as Saharan dust strongly influence particulate organic carbon
export to the deep ocean by acting as mineral ballast. However, our understanding of the processes involved remains scant.
In the present study, optical measurements were performed to monitor variations in the concentration, composition and size
distribution of particles in suspension within the water column after simulating a Saharan dust event in very clear Mediterranean
waters off Corsica in June 2010. A new methodology set up in large mesocosms proved very successful in this regard. Values
obtained simultaneously from three instruments (WetLabs ECO-BB3, WetLabs ac-9, Sequoia Scientific LISST-100) provided evidence
that (1) part of the Saharan dust pool has a rapid settling velocity (∼24–86 m day−1), (2) particulate export following a dust event is a nonlinear multi-step process and (3) export is controlled in part by
the formation of organic-mineral aggregates. This experimental study provides the first insight of the complex export processes
occurring after a dust event involving both physical and biogeochemical forcings in clear oligotrophic waters. 相似文献
15.
基于CryoSat-2数据的2010-2017年北极海冰厚度和体积的季节与年际变化特征 总被引：2，自引：2，他引：0
北极海冰变化影响着全球物质平衡、能量交换和气候变化。本文基于CryoSat-2测高数据和OSI SAF海冰密集度及海冰类型产品,分析了2010-2017年北极海冰面积、厚度和体积的季节和年际变化特征,结合NCEP再分析资料探讨了融冰期北极气温异常和夏季风异常对海冰变化的影响。结果表明,结冰期海冰面积的增加量波动较大,海冰厚度的增加量呈明显下降趋势。融冰期海冰厚度的减小量波动较大,2013年以后融冰期海冰面积的减小量逐年增加。海冰体积的变化趋势和面积变化更相似,融冰期的减小速率大于结冰期的增加速率。融冰期北极海表面大气温度异常与海冰融化量正相关。夏季风影响海冰的辐合和辐散,在弗拉姆海峡海冰的输运过程中起关键作用,促进了北冰洋表层水向大洋深层的传输。 相似文献
16.
《Marine Policy》2014
This paper summarises research and options for sustainable sea transport in Oceania with a focus on domestic shipping. This debate is situated initially within the context of the current Pacific domestic shipping scenario, a region of minute economies connected by some of the longest sea transport routes in the world. All current options are fossil fuel powered and increasingly uneconomic and unsustainable. Many routes are marginal or unviable and a vicious cycle of old ships replaced with old ships prevails. Although a central and essential issue of many Pacific communities, the option of pursuing sustainable sea transport is currently invisible within the policy space at all levels. Various renewable energy options are possible and increasingly available. Recent research finds that these have strong potential for providing benefits across multiple wellbeings. The barriers to pursing this agenda are complex and poorly understood but are perceptual and institutional more than technological. A small number of critical experiments during the last oil crisis provide critical lessons and direction. 相似文献
17.
Kunio Kutsuwada 《Journal of Oceanography》1988,44(2):68-80
Relationships of the sea level differences between Naze and Nishinoomote and between Kushimoto and Uragami with wind stress over the North Pacific are examined for interannual variability. These sea level differences are considered to be indications of Kuroshio transport in Tokara Strait and Kuroshio path south of Enshu-nada, respectively. In the sea level difference between Kushimoto and Uragami, dominant variations are found to have periods of about seven years and 3–4 years. The variation of about 7-year period, which corresponds to that in the Kuroshio path between the large meander and non-large meander, is coherent with the variation of the wind stress curl in a region about 2,400 km east of the Kii Peninsula, where negative stress curl weakens about two years before the sea level difference drops (i.e. the large meander path in the Kuroshio generates). The variation of the 3–4 year period is coherent with that of the wind stress in a large area covering the eastern equatorial Pacific, which suggests that it links with global-scale atmospheric variations. Interannual variation in sea level difference between Naze and Nishinoomote is not coherent with that between Kushimoto and Uragami, which suggests that it is not related to the variation of the Kuroshio path south of Enshu-nada, but is coherent with that of the zonally-integrated Sverdrup transport in the latitudinal zone along 30°N. It is suggested that the interannual variation of the Kuroshio transport in Tokara Strait can be explained by the barotropic response to the wind stress. 相似文献
18.
黄海夏季海雾的边界层结构特征及其与春季海雾的对比 总被引：3，自引：0，他引：3
利用海上浮标站、高分辨率数字式探空仪等多种观测手段和三维中尺度模式,对2008年7月7~11日1次夏季黄海海雾过程的边界层结构特征进行了观测分析与数值模拟,并将结果与春季的黄海海雾个例进行对比。结果表明:(1)夏季海洋大气边界层(MABL)中无强逆温层,静力稳定度较春季下降,有利于湍流的发展。加之水汽量较大,容易形成比较厚的雾(500 m);春季低空有明显逆温层,水汽供应量较少,但强稳定的层结可以使水汽局限于比较低的空中,形成比较薄的雾层(200 m)。(2)在夏季风控制下,青岛近海海洋大气边界层(MABL)中高、低层气块均来自海洋上空,温湿属性差异不大,使得温度垂直差异较小;春季MABL中高、低层气块分别来自陆地和海洋,来自陆地的暖、干气流和海洋的冷却效应导致强逆温层和雾区上方干层的出现。(3)夏季海雾的含水量大,水汽在凝结成雾的过程中放出更多的凝结潜热,雾中的海表面气温(SAT)明显高于海表面水温(SST);春季雾顶强烈的长波辐射冷却和湍流混合使雾中气温明显下降,雾中SAT与SST更加接近,甚至出现SAT小于SST。以上结果有助于对海雾形成机制的认识。 相似文献
19.
夏季浙江沿岸陆架区泥沙输运机制 总被引：3，自引：0，他引：3
基于2014年夏季浙江沿岸陆架区的水文、泥沙、底质沉积物等实测资料,运用物质通量分析方法和Gao-Collins粒径趋势分析法,探讨了泥沙的输运通量、输运方向、动力机制及净输运趋势。夏季,近岸含沙量规律性较强,由西至东逐渐降低,由南至北逐渐升高,且与潮流有非常好的对应关系,呈现出明显的潮周期变化特征。研究区净悬沙通量自岸向外海迅速变小,悬沙输运中平流输运占主导地位,其次是垂向净环流对悬沙输运的影响,近岸海域表现为向海输沙,30 m以深海域表现为东北向输沙,同时台湾暖流的屏障作用也影响了悬沙向海扩散。粒径趋势分析显示浙江沿岸陆架表层沉积物的长期输运机制为由东北向西南输运,在流系以及海底地形的影响下,中部海域出现粒径趋势较弱的沉积中心。而在夏季,悬浮泥沙主要为平行岸线向东北输运,估算每天进入研究海域的净悬浮泥沙约为1.9×106 t。 相似文献