共查询到18条相似文献，搜索用时 343 毫秒
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海潮模型的比较及海潮对地球自转变化的影响 总被引：2，自引：0，他引：2
近年来,由于卫星测高工作的开展,提供了丰富准确的观测资料,产生出许多新的海潮模型。这些海潮模型的相互比较为研究海洋的精细结构、海潮的动力学、地球动力学提供了依据。另一方面,由现代空间技术和新方法来监测地球自转中的高频变化研究领域也有长足的进展。用这些技术可检测出地球自转中的周日和半日变化,从而激发地球自转的变化。一般来说,海潮影响地球自转的高频变化有两种不同的激发机制。地球的惯性张量的变化即质量项 相似文献
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初步处理了TOPEX／POSEIDON卫星在1992年10月至1995年3月的海洋测高资料，提出了测高数据赋加面积权。进一步分析了海平面上升速率及财年项振幅和相位随纬度变化情况，揭示和证实了海平面与ENSO事件和地球自转的相关性。 相似文献
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简要说明了天文地球动力学范畴内所研究的潮汐现象，包括由日月引潮力引起的固体潮、海洋潮、大气潮和由于地球自转轴的极移引起的极潮，以及这些潮汐对地球自转和地球自转的测量产生的效应。重点阐述中国天文学界在这一领域里的研究成果。这些研究涉及潮汐影响地球自转的机制，也就是各种潮汐效应与极移、自转速率变化和章动的关系，包括构建这类关系的理论模型，分析潮汐对它们的影响，利用中国古代丰富的天象记录计算地球自转的长期减慢，计算弹性或滞弹地球的洛夫数，依据某一地球模型计算潮汐效应或章动序列等等。研究也涉及在测量地球自转参数的不同技术中各种潮汐效应对测量结果产生的影响及其改正，并涉及与潮汐有关的观测方法的优化和数据处理过程的改进。最后介绍了中国学者所发现的脉冲星的周期和周期变率测量中的潮汐效应，尽管它们的量级甚微，但不容忽视。 相似文献
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用球谐函数方法（SHM）计算了由Schwiderski海潮图和日本海海潮图引起的M2,S2,K1和O1各分潮波的综合海潮负荷参数.计算中采用了Pagiatakis（1990）地球模型的负荷Love数.结果表明SHM具有更高的计算效率和计算精度．为了真正实现±毫米的VLBI地壳运动测定精度和±0.1微伽的绝对重力测量精度,对未来海潮图模型,特别是日本海的海潮图模型的精度要求作了讨论．计算结果还表明不同地球模型的负荷Love数对计算的测站位移之差为0.7毫米,在目前测量精度下尚可以不作考虑.中国近海的海潮M2波对台北,上海,Daejeon,Okinawa,和Kagosima站的径向和水平分量位移影响可分别达±22．4～±1．0毫米和±05-±5.5毫米,表明中国近海高精度的海潮图模型对东亚测站的地壳运动高精度测量是十分重要的． 相似文献
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滞弹地球自转速率的潮汐变化 总被引：5，自引：0，他引：5
本文根据勒夫数和负荷载夫数的数值扰动原理，利用ｈａｎｄｌｅｒ摆动的理论周期作为滞弹吸收带模型参数估计的约束条件，讨论了地幔滞弹性对有效勒夫数ｋ的直接影响，以及滞弹地球对平均海潮的响应所产生的间接扰动，分析了它们对带谐潮尺度因子ｋ／Ｃ的影响，由此定义了一个具有动力学海潮、滞弹地幔和液核地球的世界时ＵＴ１潮汐变化序列，与天文新技术观测结果相比较表明，高频带谐潮变化的理论值与实测值是一致的。频散效应对低 相似文献
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本通过分析1996.0至1990.0年期间分布于太平洋海域的88个验潮站所观测到的海平面变化（SLC）资料序列，以及国际地球自转服务的日长变化（△LOD）资料序列，初步研究了海平面变化与地球自转的关系。实测资料的分析结果表明，在年限时间尺度上，日长变化与东太平洋赤道带区域的海平面变化成正相关，而与西太平洋区域的海平面变化成负相关。根据海平面变化具有位相超前的现象，证实海平面的变化可能对地球自转速率产生激发贡献。近30年的资料分析表明，太平洋的平均海平面正以每年1.8毫米的速率上升。通过本研究工作使我们认识到海平面变化的观测数据是深入革球自转研究的一种重要资料源。 相似文献
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TOPEX卫星测高资料监测平均海平面变化 总被引：4，自引：0，他引：4
利用头两年的TOPEX卫星测高资料初步测定了全球平均海平面和上海邻近海域海平面上升速率分别为1.6mm/yr和2.1mm/yr，这与验潮站资料测得的结果相近，而且比后有更高的精度。 相似文献
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TOPEX/POSEIDON is a joint American/French ocean topography experiment. It was launched by an Ariane launch vehicle on August 10, 1992 to study and map ocean circulation. The primary functions of the navigation subsystem of the TOPEX/POSEIDON project are to establish and maintain a pre-designed reference orbit, and to measure, monitor, and predict the satellite ground track continuously. To fulfill these functions, trajectory analysis is required to design and generate all trajectory related products. This paper is concerned with the trajectory functions of TOPEX/POSEIDON navigation. It describes various activities of this support function. 相似文献
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Burša Milan Kenyon Steve Kouba Jan Müller Achim Raděj Karel Vatrt Viliam Vojtíšková Marie Vítek Vojtěch 《Earth, Moon, and Planets》1999,84(3):163-176
The TOPEX/POSEIDON (T/P) satellite altimeter data from January 1, 1993to October 24, 1999 (cycles 11–261) was used for investigating
thelong-term variations in the geoidal geopotential W0 and/orin the geopotential scale factor R0 = GM/W0 (GM is theadopted geocentric gravitational constant). The mean valuesdetermined for the whole period covered are: W0 =(62 636 856.161 ± 0.002) m2 s-2, R0 =(6 363 672.5448 ± 0.0002) m. The actual accuracy is limited bythe altimeter calibration error (2–3 cm) and it isestimated
to be about ± 0.5 m2 s-2 (± 5 cm).The yearly variations of the above mean values are at the formalerror level. No long-term trend in W0, representing the oceanvolume change, was found for the seven years period 1993–9 on thebasis of T/P altimeter (AVISO) data.
No sea surface topography modelwas used in the solution.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Michael Tsimplis Marta Marcos Samuel Somot Bernard Barnier 《Global and Planetary Change》2008,63(4):325-332
Sea level trends and inter-annual variability in the Mediterranean Sea for the period 1960–2000 is explored by comparing observations from tide gauges with sea level hindcasts from a barotropic 2D circulation model, and two full primitive equation 3D ocean circulation models, a regional one and the Mediterranean component of a global one,. In the 2D model, 50% of the sea level variance was found to result from the wind and atmospheric pressure forcing. In the 3D models, 20% of the sea level variance was explained by the steric effects. The sea level residuals at the tide gauges locations, calculated by subtraction of the 2D model output from the sea level observations are significantly correlated (r = 0.4) with the steric signals from the 3D models. After the removal of the atmospheric and the steric contributions the tide-gauge sea level records indicate a period where sea level was stable (1960–1975) and a period where sea level was rising (1975–2000) with rates in the range 1.1–1.8 mm/yr. A part of the residual trend can be explained by the contribution of local land movements (0.3 mm/yr) while its major part indicates a global signal, probably mass addition, appearing after 1975. 相似文献
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海洋卫星测高技术的新进展 总被引：1，自引：0，他引：1
主要介绍９０年代发射的新一代海洋测高卫星。ＴＯＰＥＸ／ＰＯＳＥＩＤＯＮ卫星和ＥＲＳ－１卫星的情况。在简要说明这两颗测高卫星的主要任务和星载科学研究仪器之后，叙述了轨道选择的原理和精密轨道确定的情况，并介绍了最近国外利用ＴＯＰＥＸ／ＰＯＳＥＩＤＯＮ资料进行的海洋学研究和成果以及未来的测高计划。 相似文献
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Ernst J. O. Schrama 《Earth, Moon, and Planets》2004,94(1-2):143-163
Purpose of this article is to demonstrate the effect of background geophysical corrections on a follow-on gravity mission.
We investigate the quality of two effects, tides and atmospheric pressure variations, which both act as a surface load on
the lithosphere. In both cases direct gravitational attraction of the mass variations and the secondary potential caused by
the deformation of the lithosphere are sensed by a gravity mission. In order to assess the current situation we have simulated
GRACE range-rate errors which are caused by differences in present day tide and atmospheric pressure correction models. Both
geophysical correction models are capable of generating range-rate errors up to 10 μm/s and affect the quality of the recovered temporal and static gravity fields. Unlike missions such as TOPEX/Poseidon where
tides can be estimated with the altimeter, current gravity missions are only to some degree capable of resolving these (geo)physical
limitations. One of the reasons is the use of high inclination low earth orbits without a repeating ground track strategy.
The consequence is that we will face a contamination of the gravity solution, both in the static and the time variable part.
In the conclusions of this paper we provide suggestions for improving this situation, in particular in view of follow-on gravity
missions after GRACE and GOCE, which claim an improved capability of estimating temporal variations in the Earth’s gravity
field. 相似文献
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Richard Greenberg Gregory V. Hoppa Gwen Bart Terry Hurford 《Celestial Mechanics and Dynamical Astronomy》2003,87(1-2):171-188
The ice crust of Europa probably floats over a deep liquid-water ocean, and has been continually resurfaced by tectonic and thermal processes driven by tides. Tidal working causes rotational torque, surface stress, internal heating, and orbital evolution. The stress patterns expected on such a crust due to reorientation of the tidal bulge by non-synchronous rotation and due to orbital eccentricity, which introduces periodic ('diurnal') variations in the tide, are shown as global maps. By taking into account the finite rate of crack propagation, global maps are generated of cycloidal features and other distinctive patterns, including the crack shapes characteristic of the wedges region and its antipode on the sub-Jovian hemisphere. Theoretical maps of tidal stress and cracking can be compared with observed tectonics, with the possibility of reconstructing the rotational history of the satellite. 相似文献
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In this paper the tidal phenomena on the Earth are concisely specified, including solid tides, ocean tides and atmospheric tides due to the luni-solar tide-generating force, and the Earth pole tide due to the motion of the Earth's rotation axis (polar motion); as well as their effects on the Earth rotation. The outcomes of scientific researches of Chinese astronomers on these topics are described in some detail. These researches deal with the mechanisms responsible for tidal effects on the earth rotation, and on the measurements of the Earth rotation parameters. Finally, the effects discovered by Chinese researchers on the measurements of the period and change in period of pulsars are discussed. These effects are very small in magnitude but not negligible. 相似文献