共查询到20条相似文献，搜索用时 31 毫秒
1.
Thermal and chemical evolution of the terrestrial magma ocean 总被引：8，自引：0，他引：8
Yutaka Abe 《Physics of the Earth and Planetary Interiors》1997,100(1-4):27-39
The Earth is likely to have experienced a magma ocean stage during accretion. Thermal and chemical evolution of magma ocean is investigated based on a one-dimensional two-phase-flow heat and mass transfer model. Differentiation at lower mantle pressure depends on the type of magma ocean and surrounding atmosphere. If the magma ocean is formed by the blanketing effect of a solar-type proto-atmosphere, extensive differentiation proceeds at lower mantle pressure. If the magma ocean is formed by the blanketing effect of an impact-induced steam atmosphere, no differentiation at lower mantle pressure is likely. If a very deep magma ocean is formed by a giant impact, whether differentiation proceeds at lower mantle pressure or not depends on grain size, viscosity of melt and/or properties of a transient atmosphere. On the contrary, chemical differentiation likely proceeds at upper mantle pressure irrespective of magma ocean type. A shallow magma ocean can remain for 100 200 My without any heating processes. 相似文献
2.
Summary Procedures of astrodynamics are used to calculate the actual values of the secular variation of the inclination and eccentricity of the Moon's orbit due to ocean tides. The ocean tide data were taken from the resolution of the ocean tide potential into spherical functions[2] based on cotidal maps[1]. 相似文献
3.
Summary From the conservation of the mass of the earth including the hydrosphere it can be concluded that continental growth has been connected with subcrustal flow from the ocean toward the continents. Calculations show that the volume of ocean bottom subsidence nearly equals to the volume of the uplifted continental masses above the level of the primeval ocean bottom. The sea level has not changed appreciably since Precambrian. Change of ocean bottom topography and emergence of continents do not effect global sea level. Transgression and regression are figurative terms and really indicate subsidence resp. uplift of the continental crust blocks around the shoreline. 相似文献
4.
本文分析了投弃式海流电场剖面仪的发展,简介了海流感生电场的基本原理,提出了投弃式海流电场剖面仪的技术方案.根据投弃式海流电场剖面仪的实际需求,研发了XCP海流电场传感器,并通过XCP探头的自旋转(16 r/s),实现了将海流电场信号AM调制并频移至海流电场传感器的超低噪声频段,解决了在高噪声背景下快速测量纳伏级微弱海流电场信号.设计实现了XCP探头前端弱信号处理电路,对海流电场微弱信号进行滤波提取的同时可实现对海流电场同向分量进行硬件电路补偿,在一定程度上克服了XCP探头下沉引起感生电场的强干扰.在XCP探头内部采用SoPC技术实现对海流电场信号、罗盘线圈信号和温度信息的快速测量及其数字化处理,并将数字信息以UART协议及LVDS物理层数传方式发送到XCP浮筒端.开创了长度2 km、直径0.1 mm漆包线动态数据传输技术,解决了XCP探头和XCP浮筒之间的数字化数据传输问题.根据XCP探头所采集的海流电场信号与罗盘线圈信号的同相分量In、正交分量Qn、基线量Bn数据,研究了XCP探测方法,从而计算出了海流的东向与北向相对速度分量VEr、VNr.采用所研发的XCP,在我国南海海域首次采集到海面至海下千米深度的XCP海流电场信息和海洋温度信息. 相似文献
5.
Nicolas Reul Severine Fournier Jaqueline Boutin Olga Hernandez Christophe Maes Bertrand Chapron Gaël Alory Yves Quilfen Joseph Tenerelli Simmon Morisset Yann Kerr Susanne Mecklenburg Steven Delwart 《Surveys in Geophysics》2014,35(3):681-722
While it is well known that the ocean is one of the most important component of the climate system, with a heat capacity 1,100 times greater than the atmosphere, the ocean is also the primary reservoir for freshwater transport to the atmosphere and largest component of the global water cycle. Two new satellite sensors, the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius SAC-D missions, are now providing the first space-borne measurements of the sea surface salinity (SSS). In this paper, we present examples demonstrating how SMOS-derived SSS data are being used to better characterize key land–ocean and atmosphere–ocean interaction processes that occur within the marine hydrological cycle. In particular, SMOS with its ocean mapping capability provides observations across the world’s largest tropical ocean fresh pool regions, and we discuss from intraseasonal to interannual precipitation impacts as well as large-scale river runoff from the Amazon–Orinoco and Congo rivers and its offshore advection. Synergistic multi-satellite analyses of these new surface salinity data sets combined with sea surface temperature, dynamical height and currents from altimetry, surface wind, ocean color, rainfall estimates, and in situ observations are shown to yield new freshwater budget insight. Finally, SSS observations from the SMOS and Aquarius/SAC-D sensors are combined to examine the response of the upper ocean to tropical cyclone passage including the potential role that a freshwater-induced upper ocean barrier layer may play in modulating surface cooling and enthalpy flux in tropical cyclone track regions. 相似文献
6.
7.
—The Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) is used to investigate the mutual response of a tropical squall line and the ocean. Simulated squall line compares well with the observations, and consists of counterrotating vortices, and has a bow shape bulge toward the leading edge. In addition to these features, which are also shown in the previous numerical simulations, the unique results from the coupled simulation indicate that the air–sea interaction processes within the squall line are important. They affect both the atmosphere and the ocean locally. Simulated upper ocean displays significant response to the squall line with upwelling and baroclinicity. Depth of the ocean mixed layer in the coupled simulation becomes modified due to feedback processes. Ocean temperature acts as a destabilizing factor, and the salinity as a stabilizing factor. Surface turbulent fluxes from the coupled simulation are about 10% less than that of the uncoupled simulation. The SST in the coupled simulation decreases by about 0.21°C. Predicted squall line in the coupled simulation is weaker as compared to the uncoupled simulation. This is reflected in terms of differences in surface fluxes, cloud water, rain water and vertical velocities between the two simulations. 相似文献
8.
地震背景噪声特性及噪声源的分布研究逐渐成为深化背景噪声层析成像的关键问题.海岛地区由于特殊的地理位置,其背景噪声具有相对独特的特征.地脉动（约0.003~1 Hz）是地震背景噪声中能量最强的分量,其激发与特性被认为与海浪运动和固体地球之间的相互作用有关,但海岛地区地脉动特征与海洋波浪场之间的关系尚未被充分研究.本文利用西北太平洋海岛地震台站的连续记录数据、波浪浮标的实测数据以及WAVEWATCH-Ⅲ海浪模式的数值模拟结果,通过地震学和海洋学的交叉,分析海岛地区地脉动信号的时频特性及其与海洋波浪场之间的相关性,从海洋学角度对地脉动信号的特征及激发进行探讨与解释.结果表明,海岛地区地脉动信号相对于内陆地区更强,并具有明显且稳定的季节性变化特征：高频地脉动信号（0.12~0.32 Hz）在夏秋季节（5月-10月）相对较弱,而在冬春季节（11月-次年4月）相对较强,与北半球海洋活动季节性变化相一致.此外,海岛地区地脉动主要受周边海域波浪场影响,与周边海域波浪能功率密度及实测和数值模拟所得的有效波高均具有很好的互相关性.该研究结果同时表明可进一步发展利用地脉动观测数据反演海表波浪场的可能,为海洋科学研究中海表波浪场连续观测数据的获取提供地震学上的支持. 相似文献
9.
This review concentrates on the uncertainties surrounding interpretation of sea floor impedance measurements. Oceanic motionally induced signals prove to be noise generators which limit the low frequency range of usable signals. At high frequencies the screening by a thick ocean and by the sediments and rocks of layer two present insuperable barriers to detection of poorly conducting rocks in the depth range 2 to 30 km below the sea bottom by usual methods. The conductivity of this layer is important for the interpretation of all ocean impedance measurements because it determines the width of a boundary zone at the continental margins of the ocean. If the conductivity is as low as 10–5 S/m the bounding zone begins to fill the whole ocean. It is suggested that use of an active, manmade EM source can provide signals at the sea bottom capable of resolving the uncertainty. 相似文献
10.
莫霍面和居里面是认识深部过程重要的地质与地球物理界面.为了进一步理解南海深部构造活动与洋盆扩张的关系,本文以OBS剖面和深反射地震剖面作为约束,对卫星测高重力异常进行海水、沉积层影响校正,采用最小曲率位场分离方法消除局部密度体的重力影响,获取了反映莫霍面起伏的重力异常,并利用双界面模型重力场快速反演方法计算得到了南海地区莫霍面深度值.通过与居里面起伏的对比研究,发现南海莫霍面和居里面整体均表现为"洋盆浅、周缘深"的菱形特征,两者在洋陆转换区呈现明显的窄梯级带特征,反映了南海扩张期岩石圈的强烈伸展减薄、南北向构造拉张作用等深部构造过程.洋盆莫霍面和居里面的西南向楔形形态是对南海由东向西渐进式扩张的深部构造响应.洋盆南部莫霍面浅于北部,这与扩张中心逐渐向南迁移的特征一致,而洋盆居里面南深北浅的特征则可能与洋盆的简单剪切扩张方式以及洋盆北部的岩浆活动更活跃有关.南海地区莫霍面和居里面呈现交错叠置关系,南、北陆缘表现为明显的深部构造差异,说明南海为非对称式扩张.北部陆缘区居里面深度浅于莫霍面,而洋盆区和南部陆缘区居里面深于莫霍面,这与南、北陆缘性质的差异和南部陆缘复杂的中-新生代俯冲碰撞等构造演化相关,而洋盆区居里面深于莫霍面的现象推测与大洋上地幔橄榄岩蛇纹石化导致的岩石磁性增强有关. 相似文献
11.
混合是海洋中普遍存在的一种海水运动形式,对多个海洋学分支的研究具有重要的影响.随着物理海洋学的研究重心从大尺度向中小尺度现象过渡,近年来混合问题的研究重心也逐渐转向了中小尺度现象.内波与中尺度涡都是非常重要的中小尺度物理海洋学现象,对海洋能量在不同尺度中的级联发挥着重要的作用.本文基于地震海洋学研究了海洋混合参数的提取方法,并以南海内波和地中海涡旋为例进行了计算和分析.结果显示,南海内波在200~600m深度范围内所引起的混合可达10-2.79 m2·s-1左右,比大洋的统计结果10-5 m2·s-1高出两个数量级以上.而地中海涡旋所引起的湍流混合率可达10-3.44 m2·s-1左右,与大洋统计结果相比高出1.5个数量级左右,并且地中海涡旋下边界的混合要强于上边界,这一特征与前人的研究一致,另外涡旋上边界之上以及侧边界的外侧也具有非常高的混合率. 相似文献
12.
大陆上用重力数据和GPS水准数据确定(似)大地水准面,海洋上用卫星测高数据确定(似)大地水准面.由于沿海地区和近岸海域往往缺少完好的重力数据,近岸海域卫星测高数据质量相对较差,两类大地水准面在陆海相接区域精度偏低且存在拼合差.纯几何方法拟合陆海局部区域大地水准面,不能顾及大地水准面的物理特性,拟合结果不稳定.顾及到大地水准面的物理特性,依据其在局部所应满足的数学物理方程,拟合陆海局部区域大地水准面问题,转化为Laplace第一边值问题.讨论了有限元法衔接陆海局部区域大地水准面的数学思想,给出了相应的数学模型. 相似文献
13.
G. A. Zherebtsov V. A. Kovalenko S. I. Molodykh O. A. Rubtsova 《Geomagnetism and Aeronomy》2009,49(8):1264-1270
The scenario of climatic changes in the 20th century has been presented in the scope of the developed model concerning the
effect of solar activity on the parameters of the climatic system governing the energy flux, outgoing from the Earth into
space in the high-latitude regions. The regularities of changes in the circulation in the atmosphere and ocean are discussed.
Specific attention is paid to the causes of a “cold snap” in 1940–1976 in the Northern Hemisphere and the nature of an anomalous
increase in the heat content in the Earth climatic system (ocean) in 1969–1980. It has been indicated that these phenomena
result from changes in the circulation in the atmosphere and ocean (specifically, a change in the thermohaline circulation
in the Northern Atlantic), heat exchange between the ocean and the atmosphere and cryosphere. 相似文献
14.
On the electrical conductivity of the oceanic lithosphere 总被引：1，自引：0，他引：1
Charles S. Cox 《Physics of the Earth and Planetary Interiors》1981,25(3):196-201
15.
ShangFeng Zhang ChangMin Zhang MingYi Hu WenPing Gong ChuanTao Xiao AiHua Liu Dong Lü 《中国科学D辑(英文版)》2009,52(1):143-151
The base level during the deposition of Jurassic in the Qiangtang Basin shows a complete cycle from rising to falling. The base level change is closely connected with tectonic evolution of the basin, especially connected with Bangonghu-Nujiang ocean evolution process in the formation and evolution of the basin. It is also affected by climate. The Jurassic strata correspond to a long-term base level cycle sequence. The sequence is in fact a non-complete symmetrical cycle, consisting of rising hemicycle and falling hemicycle. It can be divided into 6 intermediate-term base level cycle sequences, including 2 carbonate sequences, 3 mixture sedimentary sequences of carbonate and clastic rocks and one clastic sedimentary sequence. Depositional filling characteristics during base level change show that Bangonghu-Nujiang ocean spreads in Toarcian-Bajocian ages, and is at the height of spreading of Bangonghu-Nujiang ocean in Bathonian-Oxfordian ages. In that process, sea area became smaller because of the dry climate. Eventually, marine depositional filling is ended with the subduction and collision of Bangonghu-Nujiang ocean. 相似文献
16.
A numerical model (two horizontal dimensions, vertically integrated) is used to investigate the generation of long ocean waves, ranging from 20 min to almost 2 h, at Buenos Aires continental shelf. The domain includes the Río de la Plata estuary and the continental shelf together and extends from 33.5° to 40.5°S latitude, and from 51° to 63°W longitude. Sea-level oscillations are modeled by forcing with passage of atmospheric cold fronts and atmospheric gravity waves. Both forcing mechanisms, which have been present during high activity lapses of long ocean waves, are mathematically implemented. After several numerical simulations, it is concluded that the pressure and wind fields associated to cold fronts do not generate long ocean waves in the area, though they do produce disturbances with periods longer than the tidal ones. On the other hand, it is so concluded that atmospheric gravity waves are an effective mechanism to force long ocean waves. Results obtained show that generation of long ocean waves is highly sensitive depending on the propagation direction and the phase speed of the atmospheric gravity waves. The long ocean wave event detected during the large-amplitude gravity-wave event of 13 October 1985 is successfully simulated. Finally, all our results suggest that atmospheric gravity waves are a highly effective mechanism forcing for the generation of long ocean waves in Buenos Aires coastal waters. 相似文献
17.
As is known, the secular deceleration of the Earth's diurnal rotation is explained mainly by the tidal friction in the ocean. Below we consider this mechanism in some detail, taking into account also elastic deformations of the mantle under the action of ocean loading and the interaction between the tide-generating body, ocean tidal wave, liquid outer core, and solid inner core. It is shown that elastic displacements of the core-mantle boundary under the action of ocean loading are of about the same amplitude and phase as the elastic loading displacements of the Earth's outer surface. As a result, side by side with the mechanism of secular deceleration of diurnal rotation of the mantle, there are also (1) the opposite mechanism of secular acceleration of diurnal rotation of the outer liquid core and of the solid inner core and (2) the mechanism of excitation of differential rotation in the liquid core. Taking these effects into account, we compare theoretical and modern observed data on the eastward drift of the solid inner core. It is shown that the best agreement may be obtained if the turbulent viscosity of the liquid core is about 2 × 10
3
Poise 相似文献
18.
AbstractA general linearized wave equation for a stratified rotating fluid is derived and applied to obtain a dispersion relation for waves of short latitudinal extent in a thin shell of fluid. Long period wave solutions in three ocean models are compared: (1) for a stratified ocean with both components of the rotation vector; (2) for a stratified ocean without the horizontal component of rotation, and finally, (3) for a homogeneous ocean without horizontal rotation. The inclusion of the horizontal component of the Earth's rotation is found to have no noticeable effect on the dispersion relation of long period waves; its only influence is the introduction of a vertical phase shift in the motions. The origin of this phase shift is found in the tendency of the motions to satisfy the Taylor-Proudman theorem. The phase shift is of possible oceanographic relevance only for bottom-trapped buoyancy waves in a relatively weak stratification. The differences between the three ocean models are also discussed with the help of graphs of the numerically integrated dispersion relations. The relative influences of shell thinness and stratification in inhibiting the influence of the horizontal component of the earth's rotation are also briefly discussed. 相似文献
19.
Direct injection of CO(2) into the deep ocean is receiving increasing attention as a way to mitigate increasing atmospheric CO(2) concentration. To assess the potential impact of the environmental change associated with CO(2) sequestration in the ocean, we studied the lethal and sub-lethal effects of raised CO(2) concentration in seawater on adult and early stage embryos of marine planktonic copepods. We found that the reproduction rate and larval development of copepods are very sensitive to increased CO(2) concentration. The hatching rate tended to decrease, and nauplius mortality rate to increase, with increased CO(2) concentration. These results suggest that the marine copepod community will be negatively affected by the disposal of CO(2). This could decrease on the carbon export flux to the deep ocean and change the biological pump. Clearly, further studies are needed to determine whether ocean CO(2) injection is an acceptable strategy to reduce anthropogenic CO(2). 相似文献
20.
CFC-11是评估全球海洋环流模式的一个重要工具,海水中溶解的CFC-11被用来分析全球海洋模式的通风模拟.本文在中国气象局国家气候中心发展的40层全球海洋环流模式(MOM4_L40)增加了示踪物CFC-11模块,然后利用该模式研究了CFC-11在全球海洋中的分布,并评估了模式的通风能力.对CFC-11的海表浓度、柱总含量以及大洋剖面的垂直浓度分布和渗透深度进行了分析,结果表明,与观测相比,模式较好地再现了CFC-11在海洋表面的水平分布特征,CFC-11主要储存区位于西北大西洋、副热带北太平洋及南大洋,其浓度分布与温度分布梯度相反.沿三个大洋的5个剖面的CFC-11垂直分布模拟也与观测基本吻合.模式模拟的CFC-11分布情况与全球平均经向流函数吻合,在南大洋模拟效果更加接近观测值,深海模拟效果较好,渗透深度接近观测.同时,模拟与观测相比也存在偏差.比如在北大西洋主要的存储区域,模式低估了CFC-11的吸收,这与高纬的CFC-11向低纬过度输送有关,可能是受温盐环流和强迫资料的影响.总体来说,MOM_L40模式模拟大洋吸收的CFC-11总量是理想的,通过模拟被动示踪物CFC-11很好地再现了海洋的通风能力. 相似文献