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1.
利用耦合北斗和GPS双定位系统的拉格朗日随体法水质点追踪仪，在2018年9月至2019年10月期间开展了总数为18次的洪泽湖和巢湖主要河流河水入湖后表层、中层和底层水体运移同步追踪观测，研究了两个湖泊河水入湖后的运移轨迹和速度特征。结果表明：淮河主河道河水入洪泽湖后流向南北两侧；徐洪河河口处水体表层流速在洪泽湖5条河道出入湖口处为最大；巢湖双桥河河口处水体流速受巢湖闸运行影响强烈，各层流速在7条入湖河流中最大。洪泽湖、巢湖入湖水体流速由表层至底层逐渐降低，洪泽湖各层水体流速大于巢湖。洪泽湖河口处表层水体8次测量平均流速为6.11cm/s；巢湖为5.51cm/s；二者中层流速分别为5.32和3.85cm/s；底层则分别为4.96和3.67cm/s。 相似文献
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Measurements are reported from two side-looking Doppler systems, which were used to study the discharge front located off the mouth of Chesapeake Bay. One system was a commercial 300-kHz narrow-band acoustic Doppler current profiler (ADCP), which was mounted at a depth of 0.6 m on the port side of a research ship. The other was a prototype X-band, vertically polarized, Doppler radar mounted at a height of about 4 m on the starboard side. Both velocity and backscatter intensity were measured along two beams to ranges of 120 m (ADCP) and 200 m (radar), so that by sailing alternately on each side of the front it was possible to make nearly simultaneous across-front measurements with both systems. Despite the differences in acoustic and radar scattering mechanisms, a combined backscatter intensity surface map could be made showing a continuous frontal signature about 10-m wide and 20 dB above background levels. Each system was also able to measure the same large-scale velocity change across the front, which was dominated by the discharging buoyant bay water flowing at about 50 cm/s relative to the ambient continental shelf water. However, within a 60-m wide zone, the radar system measured velocities up to 75 cm/s larger than the ADCP. Such large velocity differences arose from the radar's sensitivity to motions associated with waves reflecting from the region of strongest across-front current convergence. This frontal convergence was resolved only by the ADCP, which showed a horizontal current change of about 25 cm/s over 10 m and appeared to extend over the upper 2 m or so of the water column. These results show that the combined information from the acoustic and radar systems provide a more complete picture of the frontal currents and wave-current interactions than either system could provide alone 相似文献
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V. I. Bukreev 《Oceanology》2013,53(1):110-118
A technique and some results of laboratory experiments, in which the densification during mixing of the salt water masses with the same initial densities occurs, are presented. A graphical interpretation of the densification during mixing and an empirical formula describing the dependence of the water density on temperature and concentration of the dissolved salt NaCl at atmospheric pressure are given. Examples of spreading of the initially horizontal, inclined and vertical round jets as well as a vertical plane jet are considered. In all examples, the jet submerged up to the bottom of the experimental setup. It was found that the submergence velocity was on the order of 0.5 ± 0.1 cm/s. The influence of the double diffusion on the jet submergence velocity in the salt water is discussed. 相似文献
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海带,裙带菜过氧化物酶活性及其同工酶酶谱的比较研究 总被引：2，自引：0，他引：2
本文研究、比较了海带(Laminaria japonica),裙带菜(Undaria pinnatifido(Harv.))的过氧化物酶活性,并对分析过氧化物酶同工酶的各种方法进行了比较。海带叶片内从基部到顶部过氧化物酶活性逐渐升高,固着器内酶活性高于叶片任何部位。裙带菜中,孢子叶、茎、叶片之间酶活性无相关性。三部分中,孢子叶过氧化物酶活性最高,茎中酶活性从基部到顶部逐渐升高,叶片中则逐渐下降。海带中过氧化物酶活性比裙带菜平均高出四至五倍。同工酶分析中,比较了三种提取酶液的方法,以真空抽滤方法最佳;比较了四种染色方法,以Vitc——联苯胺方法、醋酸联苯胺方法较理想;比较了不同的材料处理后同工酶分析结果,冰冻处理与新鲜的材料效果最好,用海水室内培养后效果较差。 相似文献
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港口工程影响下莱州湾西南侧海域水动力演化特征 总被引：3，自引：1，他引：2
河流输沙、水深地形演变、大型海洋工程的建设均会对海洋水动力产生明显影响。本文基于MIKE21数值模型,对不同时期水深岸线条件下莱州湾西南侧海域的水动力演变特征及潍坊港建设对水动力的影响进行研究。结果表明,1984~2007年,黄河现行河口东南侧高流速区位置向SE向移动,莱州湾湾口及西南侧海域流速增大,增大幅度在10 cm/s左右。潍坊港10 km引堤工程的建设导致引堤端头处流速增大10~20 cm/s,引堤两侧流速减小15~20 cm/s,流向偏转量在10°~40°;潍坊港扩建工程的建设导致防波堤端头处流速增大5~20 cm/s,两侧海域流速减小5~20 cm/s,流向偏转5°~20°。黄河口沙嘴的形成对其南侧海域形成有效掩护,而潍坊港工程的建设对其两侧海域起到一定的掩护作用,导致该海域有效波高显著减小,水动力强度减弱。 相似文献
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This paper describes the first reported high-resolution remote measurements of sea-ice velocities during the summer Arctic pack-ice breakup, made with a high-frequency (HF) radar system (CODAR, for Coastal Ocean Dynamics Applications Radar) located on Cross Island, Alaska. Each 36-min observation also gives the positions of the ice edge, the moving ice, and the open water, with an azimuthal and distance resolution of5deg and 1.2 km, respectively, to a range of 15 km. The statistical uncertainties in speed are typically 2-4 cm/s. The ice breakup was observed over a two-day period starting with low ice velocity and no open water and ending with ice and current velocities of approximately 40 cm/s. The position of the ice edge is verified by a simultaneous synthetic aperture radar (SAR) image. To compare the ice, current, and wind velocities, a uniform velocity model was fitted to the measurements of radial velocity. The speed of both ice and current under free drift conditions was found to lie between 2 and 5 percent of the wind speed and the direction within20deg of the wind direction. 相似文献
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Velocity structures and transports of the Kuroshio and the Ryukyu current during fall of 2000 estimated by an inverse technique 总被引：7，自引：0，他引：7
An inverse calculation using hydrographic section data collected from October to December 2000 yields velocity structure and
transports of the Kuroshio in the Okinawa Trough region of the East China Sea (ECS) and south of central Japan, and of the
Ryukyu Current (RC) southeast of the Ryukyu Islands. The results show the Kuroshio flowing from the ECS, through the Tokara
Strait (TK), with a subsurface maximum velocity of 89 cm s−1 at 460 dbar. In a section (TI) southeast of Kyushu, a subsurface maximum velocity of 92 cm s−1 at 250 dbar is found. The results also show the RC flowing over the continental slope from the region southeast of Okinawa
(OS) to the region east of Amami-Ohshima (AE) with a subsurface maximum velocity of 67 cm s−1 at 400 dbar, before joining the Kuroshio southeast of Kyushu (TI). The volume transport around the subsurface velocity maximum
southeast of Kyushu (TI) balances well with the sum of those in TK and AE. The temperature-salinity relationships found around
these velocity cores are very similar, indicating that the same water mass is involved. These results help demonstrate the
joining of the RC with the Kuroshio southeast of Kyushu. The net volume transport of the Kuroshio south of central Japan is
estimated to be 64∼79 Sv (1 Sv ≡ 106 m3s−1), of which 27 Sv are supplied by the Kuroshio from the ECS and 13 Sv are supplied by the RC from OS. The balance (about 24∼39
Sv) is presumably supplied by the Kuroshio recirculation south of Shikoku, Japan. 相似文献
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利用非结构网格海洋环流模式(FVCOM),研究了浙闽沿岸潮余流的空间变化及其生成机制。结果表明,浙闽沿岸的潮余流具有明显的水平二维特征。根据潮余流的流速和方向,浙闽沿岸的潮余流可分为3个区域,自东北向西南,依次为区域I、区域II和区域III。区域I和区域III的潮余流较强,前者流速为0.6~2.5 cm/s,方向沿等深线指向西南;后者流速为0.5~1.5 cm/s,方向沿等深线指向东北。区域II的潮余流较弱,均小于0.6 cm/s,方向自岸向海逆时针旋转,离岸较近区域方向指向西南,离岸较远区域方向指向东北。结合浙闽沿岸的潮余流和海底地形进行分析,发现潮余流与地形β效应ddx1H成正比,这与前人研究获得的海底地形对潮流的整流机制相符合,表明浙闽沿岸海域陡峭的海底地形对潮流有明显的整流作用。 相似文献
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通过分析2018–2019年粤西阳江沿岸流海域多站点周年观测水文气象实测资料,发现2019年春季和夏季阳江沿岸流海域存在激流现象。研究结果表明:（1）2019年5月5日凌晨6时,观测站点2 m水深处流速达到164.7 cm/s,9 m水深处流速达到127.6 cm/s。2019年8月1日凌晨4时至5时,阳江沙扒海域2 m水深处流速达到161.8 cm/s,9 m水深处流速达到156.6 cm/s。（2）粤西沿岸流阳江20～30 m水深海域春夏季突发性强流具有典型的激流特征。激流在涨急时刻发生在海洋表层,持续2～4 h。（3）在西南风与东北风转换期间,粤西沿岸海域容易形成海水幅聚带,近岸海域海平面上升,外海海域海平面下降,强劲的自岸向外水平压强梯度力导致近岸海水加强向西运动,从而产生激流。 相似文献
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围海建设对天津近海水动力环境的影响研究 总被引：1，自引：0，他引：1
基于FVCOM三维水动力模型研究了围填海建设对天津近海海域水动力的影响。结果表明:针对近岸海域的围填建设,围填造陆对天津近海海域的潮流场有一定的影响,围填建设区北部和南部区域流速增大,右侧区域流速减小,流速变化在-30～20cm/s之间,平均变化率为30.4%,流向变化在-50°～40°之间;余流场变化幅度较大,在1～17.9cm/s之间。 相似文献
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Motohiko Kashima Shiro Imawaki Shin-Ichiro Umatani Hiroshi Uchida Yuji Hashibe Hiroshi Ichikawa Masao Fukasawa 《Journal of Oceanography》2003,59(3):291-301
Theoretically, the geostrophic approximation holds for the low-frequency flow field, but no detailed examination has been
done on how well the estimated geostrophic velocity corresponds with the observed velocity. Intensive surveys were carried
out during 1993–1995 in the Kuroshio and its recirculation regions south of Shikoku, Japan, including repeated hydrographic
surveys and direct current measurements at nominal depths of 700, 1500 and 3000 m. For these depth intervals, vertical differences
of estimated geostrophic velocity are compared with those of observed velocity. For the intermediate layer (between 700 and
1500 m depths), the slope of the regression line is 0.99, correlation coefficient is 0.98, and the root-mean-square of difference
from geostrophic balance is 2.8 cm/s which is close to the estimated error of 2.1 cm/s. For the deep layer (between 1500 and
3000 m depths), the corresponding values are 0.82, 0.93, 1.2 cm/s and 2.0 cm/s, respectively. The results indicate that the
estimated geostrophic velocity compares well with the observed velocity in these regions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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本文利用三维数值模型(ROMS-Co Si NE)分析了整个加利福尼亚流系水平流场的季节性演变过程,研究了美国加州中部海域流场垂直结构的季节性变化特征,并探讨了其动力学机制。研究发现:(1)数值模型能够较为准确的模拟流场的季节性变化,与浮标观测数据以及前人的研究结果符合良好;(2)从表层到200m,加利福尼亚潜流向高纬度扩张,近岸上升流急流则向高纬度撤退,加州南部海域的中尺度涡更显著;(3)在加州中部海域,近岸急流的最大值(约15cm/s)发生在夏季,位于近岸的表层海域;加利福尼亚潜流最大值(约4cm/s)发生于冬季,出现在离岸100km的125m处;加利福尼亚流在春季达到全年最大值(约5cm/s),流轴位于离岸(400—600km)的表层海水。加利福尼亚流系的流场具有显著的季节性变化,研究进一步表明这主要受地转关系调控。 相似文献
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基于天津港主航道连续观测点31 d的实测海流资料,利用调和分析对主航道潮流和余流特征进行研究,同时结合同步风速资料研究风对表层余流的影响。结果表明:(1)航道附近属于弱流海区,表层平均流速为31.4 cm/s,流速总体上由表至底逐渐减小,流速方向大致集中在NW—SE向。(2)观测海域潮流以正规半日往复潮占主导,优势分潮为M2,浅水分潮较为显著,涨潮流流速大于落潮流流速。(3)观测期间表层平均余流流速为2.8~13.8 cm/s,随着深度增加余流流速逐渐减小,方向大多为NW向。该站表层余流受风的影响显著,东南风将使余流方向偏向西北。 相似文献
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雨生红球藻的细胞周期初探 总被引：15，自引：2，他引：13
于１９９７年在青岛利用显微镜连续观察技术研究了雨生红球藻的细胞繁殖方式和动力学。结果表明,该藻细胞周期分为流动和不动２个阶段。每一阶段主要以无性生殖产生孢子的方式完成增殖。正常条件下游动细胞主要产生２、４个,偶尔产生２、４个,偶尔产生８个游动孢子,游孢子从孢子囊释放后为游动细胞。环境不适时流动细胞以及流动孢子失去鞭毛转入不动阶段。不动细胞主要形成４、８个,偶尔也能形成２０多个不动孢子,该过程不一定 相似文献
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Observations and analyses of floc size and floc settling velocity in coastal salt marsh of Luoyuan Bay, Fujian Province, China 总被引：1，自引：0，他引：1
In coastal environments, fine-grain sediments often aggregate into large and porous flocs. ElectroMagnetic Current Meters (EMCM) and Laser In Situ Scattering and Transmissometry (LISST-ST) have been deployed within a Spartina alterniflora marsh of the Luoyuan Bay in Fujian Province, China, to measure the current velocity, the floc size and the settling velocity between 15 and 22 January 2008. During the observations, the near-bed water was collected in order to obtain the suspended sediment concentration (SSC) and constituent grain size. Data show that: (1) the nearbed current velocities vary from 0.1 to 5.6 cm/s in the central Spartina alterniflora marsh and 0.1–12.5 cm/s at the edge; (2) the SSCs vary from 47 to 188 mg/dm 3 . The mean grain size of constituent grains varies from 7.0 to 9.6 μm, and the mean floc sizes (MFS) vary from 30.4 to 69.4 μm. The relationship between the mean floc size and settling velocity can be described as: w s =ad b , in which w s is the floc settling velocity (mm/s), a and b are coefficients. The floc settling velocity varies from 0.17 to 0.32 mm/s, with a mean value of 0.26 mm/s, and the floc settling velocity during the flood tide is higher than that during the ebb tide. The current velocity and the SSC are the main factors controlling the flocculation processes and the floc settling velocity. 相似文献
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M. Ergin 《Geo-Marine Letters》1995,15(1):51-58
The uppermost 5–6 cm of the sediments (between 8 and 2248 m water depths) were studied to understand the effects of varying redox conditions on the Mn distribution in the recent sediments of the Black Sea. It was found that most Mn concentrations are consistent with the average abundance in crustal and/or sedimentary rocks. There exist no important differences between Mn concentrations in oxic (shallower water; <70 m) and anoxic (deeper water; 120 m) sediments. Previously reported Mn-enrichment above the Black Sea oxic/anoxic interface, due to the peculiar redox cycling, shows no significant contribution of Mn to the bottom sediments. A marked relationship between total Mn concentrations and clay/mud contents at shelf depth along the southern Black Sea margin indicates increased accumulation of Mn in association with the fine-grained particles and eastward water circulation. 相似文献