共查询到19条相似文献，搜索用时 55 毫秒
1.
利用为期一年的卫星遥感温度（SABER/TIMED）资料重建了120°E子午圈内中间层和低热层大气潮汐各主要频率分量（周日、半日和8小时潮汐）.这些主要频率分量随高度振幅增大，在97 km高度达到显著的振幅；其中迁移性周日潮汐在97 km高度出现极大振幅，然后随高度衰减.本文从考察迁移性成分和非迁移性成分各自在总潮汐中贡献角度出发，着重讨论了那些对形成该子午圈中97 km高度上整体潮汐扰动起控制作用的潮汐成分.结果显示，对周日和半日频率这两种潮汐而言，迁移性成分控制了它们的总体时空分布.在春分季节，迁移性周日潮的控制作用最显著，决定了赤道和两半球热带的活动中心；其中北半球副热带地区的季节变化形势与以往利用武汉（30°N，114°E）流星雷达风测量资料开展分析得到的结果是一致的；其他季节受非迁移性成分明显影响，例如，在本文关注的2005年中，夏至季节受（1，0）模、（1，-3）模和（1，-2）模的共同影响形成了从赤道向南延伸的活动中心，极值中心位于赤道附近，振幅达到了20 K以上，是全年的最大值.受迁移性成分控制，半日潮活动主要出现在两半球热带地区，北半球活动中心位于秋分季节（振幅达到13 K），南半球活动中心位于春分和夏至之间.其他季节受非迁移成分的影响，形成若干分布在两半球的活动中心.在本文关注的40°S～40°N范围内，与周日潮和半日潮相比，8小时潮汐具有显著较低的振幅；另外，虽然迁移性成分在一年中的大部分时间系统地分布在两半球热带地区，但是非迁移成分具有与迁移性成分相当或更大的振幅，在整体上控制了这种潮汐的时空分布. 相似文献
2.
《地球物理学进展》2017,(4)
本文利用中国廊坊站(39.4°N,116.7°E)流星雷达在2012年4月1日至2013年3月31日期间的水平风场观测数据,分析了廊坊上空中间层和低热层(MLT,80~100 km)大气纬向风、经向风潮汐的季节变化特征.研究表明:廊坊MLT区域周日潮汐和半日潮汐波动比较显著,有明显的季节变化特征.周日潮汐振幅在88 km以下为半年变化,极大值位于2-3月和10月,极小值位于冬、夏季;在88 km以上为周年变化,振幅冬末春初最强,夏季最弱.周日潮汐相位在秋、冬季比春、夏季提前.半日潮汐主要呈现半年变化,在5月和9月最强,冬、夏季最弱.半日潮汐相位在春、夏季比秋、冬季提前.此外,廊坊风场潮汐的观测结果与WACCM4模式模拟结果进行比较,结果表明两者的主要特征相似,在细节上有显著区别.与40°N附近其他站点风场潮汐观测结果的比较结果表明中纬度MLT风场潮汐有显著的随经度变化特性. 相似文献
3.
作为一种刻画行星尺度大气波动基本结构的函数，Hough函数为开展有关大气潮汐全球结构的分析提供了具有物理基础的手段，它们也被作为一种数值工具应用于大气模式中以提高数值积分的效率.本文介绍了我们以拉普拉斯潮汐方程为基础，在发展求取Hough函数方面取得的进展，包括对有关计算方案和详细步骤的说明.针对39种分别具有三种主要频率，即周日、半日和1/3日，与此同时纬向波数落在[6，6]区间的潮汐成份，通过计算得到了与每一种成份对应的本征值、本征函数（Hough函数）集合.作为计算结果的示例，本文给出了针对迁移性周日潮和迁移性半日潮开展计算取得结果.这些结果说明这些函数具有正确的空间结构，与此同时还说明相关的本征值计算结果都达到了相当准确的水平.所有这些结果显示当前计算结果已经可以满足普通的应用. 相似文献
4.
本文利用地磁台站和卫星磁场数据,对平流层爆发性增温(Sudden Stratospheric Warming,SSW)期间赤道电集流(Equatorial Electrojet,EEJ)中太阴半日潮汐的经度变化进行了统计学分析.结果显示,SSW期间秘鲁和印度扇区的EEJ中太阴半日潮汐明显增强,且存在显著的经度差异.秘鲁扇区的EEJ中太阴半日潮汐达到峰值的时间要早于印度扇区,进一步分析发现峰值时间的经度差异与太阳活动和准两年振荡相位有关.此外,SSW期间秘鲁扇区EEJ的太阴半日潮汐峰值强度比印度扇区高.对比不同经度带背景磁场的强度与太阴半日潮汐的峰值幅度的关系,可以看出SSW期间EEJ太阴半日潮汐峰值幅度的经度差异与背景磁场强度有关,但也存在其他物理过程的影响. 相似文献
5.
气压和温度对南极中山站重力场观测的影响研究 总被引：4，自引：1，他引：3
对南极中山站1998-12-26-2000-01-01的气压、温度和重力场潮汐及非潮汐变化观测资料进行了综合对比与相关分析,研究了气压和温度变化对重力场观测的影响.结果表明,在南极中山站,重力场和气压变化存在很强的相关性,气压变化对重力场的影响非常大,且随频率的增加呈减少的趋势气压在长周期、周日、半日和1/3日频段的平均重力导纳值分别为-1.6834,-1.5304,-0.9450,-0.8791μGal/hPa,与中、低纬度地区的同类观测结果之间存在很大的差异,具有明显的"反变气压计"效应.重力场和温度变化的相关性随时间不同存在较大的差异,温度对重力场观测的影响主要反应在长周期频段,温度的平均重力导纳值为0.6296μGal/℃,对重力场高频(包括周日、半日和1/3日潮汐频段)扰动的贡献极小.气压和温度改正后,潮汐各频段的标准偏差有不同程度的下降,周日和半日频段的标准偏差从6.63μGal和1.41μGal分别下降到2.11μGal和1.13μGal,各重力潮波的观测精度都有提高;重力残差的振幅谱在各频段,特别是在长周期频段明显降低. 相似文献
6.
利用阿德莱德（35°S，138°E）和武汉（30.6°N，114.5°E）的流星雷达观测数据首次给出了80~100 km高度上周期为12.66太阳时的大气太阴半日潮汐（N2潮）的季节、高度、年度变化及其与周期为12.42太阳时的大气太阴半日潮汐（M2潮）的对比分析.分析结果表明：武汉和阿德莱德的N2潮和M2潮均有明显的季节、高度和年度变化.N2潮与M2潮的幅度比值大于其引力势之比0.191，在某些年份的不同季节和高度上，N2潮的幅度甚至大于M2潮的幅度.大多幅度之比接近或超过N2潮和M2潮引力势之比的2倍.中低热层的大气太阴N2潮汐值得关注. 相似文献
7.
本文应用中国大陆两条经度链和两条纬度链上共37个地电场台站的观测数据,研究了地电场日变化的时/频域特征,结果认为,绝大多数台站的日变化表现为两次起伏的半日波,紧临午前午后出现;按FFT振幅谱由大到小,其主要周期成分依次为12.4/12、8、24 h等,与潮汐调和分量周期一致;纬度效应主要表现为沿经度链的日变化幅度与纬度高/低有关,日变化相位差与当地时差吻合;Loyd季节的J季节日变化幅度最大、E季节其次、D季节最小.讨论了产生日变化主要周期成分的可能原因,认为月日引潮力引起的地面涡旋电流强度变化和太阳风引起的空间电磁活动共同产生了地电日变化的半日波周期成分. 相似文献
8.
采用二维可压缩大气中重力波非线性传播的数值模式, 研究了重力波与潮汐之间的非线性相互作用. 结果表明, 重力波在潮汐背景中传播时, 先后在z = 75~85, z = 90~110和z = 15~130 km 3个高度上发生不稳定. 垂直波长首先由12 km变成27 km左右, 新生成的长波逐渐被压缩并再次生成20 km左右的长波. 长波和短波出现的高度分别对应于反向和同向背景风场区域的高度. 在重力波主要的破碎区域(90~110 km)以上, 仍有部分重力波继续上传. 重力波在上传过程中除了对背景风场加速之外, 还增大了潮汐的振幅, 特别是在重力波发生不稳定之后, 对潮汐振幅的放大作用更加明显. 相似文献
9.
采用武汉台超导重力仪(SG C032)14年多的长期连续观测资料,研究了固体地球对二阶和三阶引潮力的响应特征,精密测定了重力潮汐参数,系统研究了最新的固体潮模型和海潮模型在中国大陆的有效性.采用最新的8个全球海潮模型计算了海潮负荷效应,从武汉台SG C032的观测中成功分离出63个2阶潮汐波群和15个3阶潮汐波群信号,3阶潮波涵盖了周日、半日和1/3日三个频段.重力潮汐观测的精度非常高,标准偏差达到1.116 nm·s-2,系统反映了非流体静力平衡、非弹性地球对2阶和3阶引潮力的响应特征.结果表明,现有的武汉国际重力潮汐基准在半日频段非常精确,但在周日频段存在比较明显的偏差,需要进一步精化.对于中国大陆的大地测量观测,固体潮可以采用Dehant等考虑地球内部介质非弹性和非流体静力平衡建立的固体潮理论模型或Xu 等基于全球SG观测建立的重力潮汐全球实验模型作为参考和改正模型,海潮负荷效应应该采用Nao99作为改正模型. 相似文献
10.
利用武汉地区2006年1月11～15日的Radiosonde加密观测数据，本文讨论了当地对流层与低平流层（25 km以内）温度、纬向风与经向风周日潮汐变化的振幅与相位（振幅最大值对应的时间）的变化，同时与其他地区统计平均的结果进行了比较. 发现风场振幅的变化与统计平均的结果存在较大差异，这归结于当地冬季对流层内强烈变化而低平流层内相对稳定的风场；温度在23 km以上存在稳定的周日变化，气压在更大的范围内存在与温度类似的周日变化，这使得在23 km以上大气密度的周日变化十分微弱，在各个高度上近似为一个常数. 相似文献
11.
A short general explanation of tidal forces and tidal effects is given. The influences of Earth tides and ocean tides on the Earth's rotation vector are presented. Today, the theoretical models for periodic variations in the Earth's rotation and in polar motion can be compared with precise measurements done by modern space techniques. Secular changes of the Earth's rotation due to interactions within the Earth-Moon-system are also discussed. 相似文献
12.
Richard W. Zurek 《Pure and Applied Geophysics》1985,123(6):902-920
The relationships between the linearized meteorological variables as expressed in geometric height and in log-pressure coordinates are derived from the assumptions of classical atmospheric tidal theory. While the horizontal velocity components are the same to first-order in the two coordinate systems, a linearized vertical velocity differencew-H
0 occurs because of the periodic vertical displacement of the constant pressure surfaces due to time-dependent, hydrostatic density perturbations; a linearized temperature differenceT- also results when these displacements occur in the presence of a zero-order vertical gradient of temperature. Both of these differences can be expressed in terms of the tidal geopotential field. For a given tidal mode, both differences are generally proportional to the square root of the ratio of the tidal mode's equivalent depth and the atmospheric scale height; the temperature difference is also proportional to the background temperature lapse rate. It is further shown that the two classical tidal vertical structure equations commonly derived in their respective geometric height and log-pressure coordinate systems are in fact identical to first-orderas long as the same thermotidal forcing function is used. Expressions for the zonal-mean components of the tidal bilinear fluxes, formed by zonally averaging the product of two longitudinally varying, linearized tidal fields, are also derived for the two coordinate systems. For the bilinear fields the largest relative differences (a few tens of percent) are for the tidal zonal-mean forcing per unit mass of the zonal wind. For Earth and Mars, differences between the tidal vertical velocity fields are generally less than 25% but may be significantly larger in the Martian atmosphere during one of its episodic planetary-scale dust storms. Tidal temperature differences are generally smaller. 相似文献
13.
14.
L. Li D. A. Barry C. Cunningham F. Stagnitti J. -Y. Parlange 《Advances in water resources》2000,23(8):176
Previous studies on tidal dynamics of coastal aquifers have focussed on the inland propagation of oceanic tides in the cross-shore direction, a configuration that is essentially one-dimensional. Aquifers at natural coasts can also be influenced by tidal waves in nearby estuaries, resulting in a more complex behaviour of head fluctuations in the aquifers. We present an analytical solution to the two-dimensional depth-averaged groundwater flow equation for a semi-infinite aquifer subject to oscillating head conditions at the boundaries. The solution describes the tidal dynamics of a coastal aquifer that is adjacent to a cross-shore estuary. Both the effects of oceanic and estuarine tides on the aquifer are included in the solution. The analytical prediction of the head fluctuations is verified by comparison with numerical solutions computed using a standard finite-difference method. An essential feature of the present analytical solution is the interaction between the cross- and along-shore tidal waves in the aquifer area near the estuary’s entry. As the distance from the estuary or coastline increases, the wave interaction is weakened and the aquifer response is reduced, respectively, to the one-dimensional solution for oceanic tides or the solution of Sun (Sun H. A two-dimensional analytical solution of groundwater response to tidal loading in an estuary, Water Resour Res 1997;33:1429–35) for two-dimensional non-interacting tidal waves. 相似文献
15.
The resonances of tides in the coupled open ocean and shelf are modeled by a mechanical analogue consisting of a damped driven larger mass and spring (the open-ocean) connected to a damped smaller mass and spring (the shelf). When both masses are near resonance, the addition of even a very small mass can significantly affect the oscillations of the larger mass. The influence of the shelf is largest if the shelf is resonant with weak friction. In particular, an increase of friction on a near-resonant shelf can, perhaps surprisingly, lead to an increase in ocean tides. On the other hand, a shelf with large friction has little effect on ocean tides. Comparison of the model predictions with results from numerical models of tides during the ice ages, when lower sea levels led to a much reduced areal extent of shelves, suggests that the predicted larger tidal dissipation then is related to the ocean basins being close to resonance. New numerical simulations with a forward global tide model are used to test expectations from the mechanical analogue. Setting friction to unrealistically large values in Hudson Strait yields larger North Atlantic M2 amplitudes, very similar to those seen in a simulation with the Hudson Strait blocked off. Thus, as anticipated, a shelf with very large friction is nearly equivalent in its effect on the open ocean to the removal of the shelf altogether. Setting friction in shallow waters throughout the globe to unrealistically large values yields even larger open ocean tidal amplitudes, similar to those found in simulations of ice-age tides. It thus appears that larger modeled tides during the ice ages can be a consequence of enhanced friction in shallower water on the shelf in glacial times as well as a reduced shelf area then. Single oscillator and coupled oscillator models for global tides show that the maximum extractable power for human use is a fraction of the present dissipation rate, which is itself a fraction of global human power consumption. 相似文献
16.
气压变化及其对地壳形变和深井水位的影响 总被引：2，自引：0，他引：2
根据北京塔院地区1984和1985年的微气压计记录采用频谱分析和调和分析两种方法得出了大气潮谱的详细结构;用负荷勒甫数代替潮汐勒甫数,仿照固体潮的有关公式,导出了大气潮引起的地壳应变和地倾斜公式;使用北京塔院井的水位观测资料结合当地的气压资料,分析了气压变化对深井水位的影响.理论计算和实测资料的分析结果基本相符,特别是两种结果都得出S2大气潮引起的体膨胀约为S2固体潮体膨胀的20％. 相似文献
17.
根据北京塔院地区1984和1985年的微气压计记录采用频谱分析和调和分析两种方法得出了大气潮谱的详细结构;用负荷勒甫数代替潮汐勒甫数,仿照固体潮的有关公式,导出了大气潮引起的地壳应变和地倾斜公式;使用北京塔院井的水位观测资料结合当地的气压资料,分析了气压变化对深井水位的影响.理论计算和实测资料的分析结果基本相符,特别是两种结果都得出S_2大气潮引起的体膨胀约为S_2固体潮体膨胀的20％. 相似文献
18.
Lunar and solar atmospheric tidal oscillations have been determined with satisfactory accuracy from 17 years 11 months of mean sea-level barometric pressure observations taken at Nandi, Fiji. In many respects, the results are consistent with previous tidal determinations in the south-west Pacific region, although these are few and widely scattered. However, the mean annual amplitude of the lunar tide at Nandi, as determined in this study, 88 b, is much greater than might have been expected from currently available global amplitude maps. Nevertheless, the probable correctness of this result has been confirmed by the analysis of nearly 6 years of similar data from Nausori (130 km E.S.E. of Nandi), which yielded a mean annual lunar amplitude of 88 b, compared with a Nandi amplitude of 83 b for a closely corresponding period. 相似文献
19.
V. V. Alekseenko Yu. M. Gavrilyuk D. M. Gromushkin D. D. Dzhappuev A. U. Kudzhaev V. V. Kuzminov O. I. Mikhailova Yu. V. Stenkin V. I. Stepanov 《Izvestiya Physics of the Solid Earth》2009,45(8):709-718
The results of the long-term recording of thermal neutron flux near the Earth’s surface with the use of an unshielded scintillation thermal-neutron detector are presented. The data obtained indicate the presence of periodic variations in the thermal neutron flux with the lunar diurnal and the lunar monthly periods. A hypothesis about the existence in the Earth’s crust of radon-neutron tidal variations in the concentration of thermal neutrons, correlated with the Moon’s phases and which have the gravitational origin, is formulated and confirmed experimentally. A simple mathematical model is proposed, which satisfactorily describes the observed variations. The case of the anomalous behavior of thermal neutrons is presented, which correlates with the high local seismic activity. 相似文献