共查询到17条相似文献，搜索用时 921 毫秒
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研究和实施了由卫星测高数据计算垂线偏差，用莫洛 金斯基（Molodensky）公式反演 大地水准面高，由此求得我国海域大地水准面高. 为了检核，将测高垂线偏差利用逆维宁迈 纳斯（Vening Meinesz）公式反演重力异常，与海上船测重力值进行了外部检核；同时还用 司托克斯（Stokes）公式，将上述反演的重力异常计算大地水准面高，与莫洛金斯基公式直 接解得的相应结果进行比较作为内部检核. 在积分计算中充分应用了FFT的严格公式.由重力和GPS水准数据确定的陆地大地水准面，和主要由卫星测高数据确定的海洋大地水准 面，二者之间一般都存在以系统误差为主的拼接差，本文分析了产生这一现象的主要原因, 并结合我国在陆海大地水准面拼接区重力资料稀疏的实际，提出了新的拼接技术，最后将拟 合参数校正中国全部海域的重 力大地水准面，以最大限度地削弱拼接点和制约测高海洋大地水准面可能存在的系统误差. 相似文献
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本文研究了基于泊松小波径向基函数融合多代卫星测高及多源重力数据精化大地水准面模型的方法.分别以沿轨垂线偏差和大地水准面高高差作为卫星测高观测量,研究了使用不同类型测高数据对于大地水准面建模精度的影响.针对全球潮汐模型在浅水区域及部分开阔海域精度较低的问题,引入局部潮汐模型研究了不同潮汐模型对于大地水准面的影响.数值分析表明:相比于使用沿轨垂线偏差作为测高观测量,基于沿轨大地水准面高高差解算得到的大地水准面模型的精度更高,特别是在海域区域,其精度提高了2.3cm.由于使用沿轨大地水准面高高差作为测高观测量削弱了潮汐模型长波误差的影响,采用不同潮汐模型对大地水准面解算的影响较小.总体而言,船载重力及测高观测数据在海洋重力场的确定中呈现互补性关系,联合两类重力场观测量可以提高局部重力场的建模精度. 相似文献
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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
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雷达卫星测高数据质量是测高在大地测量学、地球物理学和海洋学等领域应用研究的关键。在沿海海域,测高波形受到地形和地球物理环境等污染,测高数据精度低于开阔海域的测高数据。提出了一种新的测高波形重定方法,即多子波参数重定方法（MSPR）,用于改善沿海海域的测高数据质量。由测高数据,利用最小二乘配置法解算沿海重力异常,给出了对应的方差-协方差矩阵。利用MSPR对台湾岛周边海域的Geosat／GM波形数据进行重定,与台湾岛大地水准面进行比较,MSPR重定结果精度要优于常用的β-5参数方法重定结果和GDR数据。利用重定后的测高数据,由最小二乘法计算了台湾岛近海海域的重力异常。与船测重力数据进行比较,由重定数据得到的结果精度优于GDR结果。 相似文献
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为了提高测高重力恢复计算的精度,本文利用新方法计算沿轨测高垂线偏差分量,并在对逆Vening Meinesz公式的FFT算法进行分析的基础上导出了内区效应的计算公式.结果证明内区效应与逆Vening Meinesz公式奇异区内垂线偏差分量的梯度及奇异区面积的大小有关,与重力异常计算点及其附近的奇异区内的垂线偏差无直接关系.最后利用ERS_1卫星测高数据,根据本文提出的方法计算垂线偏差分量,采用本文导出的内区效应公式计算了北大西洋6°×6°区域内区效应对测高重力结果的影响. 相似文献
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在流体静力平衡状态下,海洋Coriolis力和压力梯度平衡就形成地转流,世界上大多数海流都近似为地转流.本文利用卫星测高交叉点方法计算海洋表面地转流速度,分析了利用测高交叉点计算地转流速度的不确定性,上升和下降弧段的海面倾斜在分辨率50 km上可以达到10-7量级,才可能获得优于10 cm/s的地转流速度.在低纬度或者纬度接近卫星轨道倾角的地区,由交叉点方法计算的地转流速度精度低于中纬度地区.以中国台湾东部黑潮为试验区,利用最新的中国台湾周边海域大地水准面模型参考场计算高精度的大地水准面高,利用TOPEX/Poseidon和Jason-1的GDR数据(2002~2005年)计算海面高,然后计算交叉点的动力高,确定交叉点的地转流速度,结果与中国台湾NCOR(National Center for Ocean Research)的流速基本一致. 相似文献
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利用欧空局发布的三组GOCE引力场模型及CNES-CLS 2010平均海面高数据,计算得到了全球的稳态海面地形,进而得到了全球地转流速度图.在此基础上重点对黑潮进行了对比分析.结果表明:GOCE不同组解的稳定性较好,所计算的稳态海面地形的差异基本在厘米量级内,这间接表明了GOCE引力场模型提供的大地水准面的精度达到了厘米量级.此外,通过将GOCE与GRACE相应结果进行对比发现,GOCE可提供更多的局部信息,特别是对于流速快、水流窄的边界流,如黑潮、墨西哥湾流等,GOCE所得结果更加清晰,速度也更精确. 相似文献
10.
精化大地水准面中的几个问题 总被引：5，自引：0，他引：5
根据近年来精化大地水准面的研究结果，对人们比较关系的５个方面的问题加以综述和探讨：（１）大地水准面的定义；（２）精化大地水准面的作用；（３）由似大地水准面改化为大地水准面；（４）海面地形对大地水准面的影响及其改正；（５）高程异常中的零阶及其误差。 相似文献
11.
Free-Air Anomalies (FAA) for the Norwegian marine area including some parts of the North Sea, the Norwegian Sea and the Barents
Sea are computed from satellite altimetry data. A total of 84 cycles of ERS2 along-track data, 25 cycles of ENVISAT along-track
data and high density ERS1 data during its geodetic mission are used. The new geopotential model from the Gravity Recovery
and Climate Experiment (GRACE) mission, GGM02S (Tapely et al., 2005) is used to compute the long wavelength contributions
of the geoid and the FAA. To correct data for mean dynamic topography, the available Levitus climatology model (Levitus and
Boyer, 1994) is used. Corrected data are then used to compute along-track gradients in each cycle-pass to suppress the orbital
and the atmospheric errors below the noise level of the altimeter. Resulted gradients are then stacked and the east-west and
the north-south components of the deflection of verticals are computed where ascending and descending tracks meet each other.
Finally, the inverse Vening-Meinesz formula is implemented on the gridded deflections to compute FAA. Results are then compared
with available marine and airborne data. Standard deviations of ± 4.301 and ± 6.159 mGal in comparison with airborne and marine
FAA were achieved. Thereafter, the derived anomalies are combined with marine and airborne FAA together with the land FAA
to compute a fine resolution geoid for Norway and the surrounding marine areas. This geoid is evaluated over sea and land
with the synthetic geoid (the geoid derived from the mean sea surface by subtracting the mean dynamic topography) and Global
Positioning System (GPS)-levelling and the standard deviations of the differences are ± 20.9 and ± 12.8 cm respectively.
ali.soltanpour@ntnu.no, hossein.nahavandchi@ntnu.no, kourosh.ghazavi@ntnu.no 相似文献
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A method for splitting sea surface height measurements from satellite altimetry into geoid undulations and sea surface topography is presented. The method is based on a combination of the information from altimeter data and a dynamic sea surface height model. The model consists of geoid undulations and a quasi-geostrophic model for expressing the sea surface topography. The goal is the estimation of those values of the parameters of the sea surface height model that provide a least-squares fit of the model to the data. The solution is accomplished by the adjoint method which makes use of the adjoint model for computing the gradient of the cost function of the least-squares adjustment and an optimization algorithm for obtaining improved parameters. The estimation is applied to the North Atlantic. ERS-1 altimeter data of the year 1993 are used. The resulting geoid agrees well with the geoid of the EGM96 gravity model. 相似文献
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Transformation between gravimetric and GPS/levelling-derived geoids using additional gravity information 总被引：1，自引：0，他引：1
The transformation from the gravimetric to the GPS/levelling-derived geoid using additional gravity information for the covariance function of geoid height differences has been investigated in a test area in south-western Canada. A “corrector surface” model, which accounts for datum inconsistencies, long-wavelength geoid errors, vertical network distortions and GPS errors, has been constructed using least-squares collocation. The local covariance function of geoid height differences is usually obtained from residual values between the GPS/levelling and gravimetric geoid heights after the elimination of all known systematic distortions. If additional gravity data (in the form of gravity anomalies) are available, the covariance function of geoid height differences can be determined by the following steps: (1) transforming the GPS/levelling-derived geoid heights into gravity anomalies; (2) forming differences between the computed in step 1 and given gravity anomalies; (3) determining the parameters of the local covariance function of the gravity anomaly differences; (4) constructing an analytical covariance model for the geoid height differences from the covariance function of the gravity anomaly differences using the parameters derived in step 3. The advantage of the proposed method stems from the great number of gravity data used to derive the empirical covariance function. A comparison with the least-squares adjustment shows that the standard deviation of the residuals of the predicted geoid height differences with respect to the control point values decreases by 2.4 cm. 相似文献
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Estimation of ocean circulation is investigated via assimilation of satellite measurements of the dynamic ocean topography (DOT) into the global finite-element ocean model (FEOM). The DOT was obtained by means of a geodetic approach from carefully cross-calibrated multi-mission altimeter data and GRACE gravity fields. The spectral consistency was achieved by consistently filtering both, the sea surface and the geoid. The filter length is determined by the spatial resolution of the gravity field and corresponds to approximately 241 km half width for the GRACE-based gravity field model ITG-Grace03s.The assimilation of the geodetic DOT was performed by employing a local singular evolutive interpolated Kalman (SEIK) filter in combination with the method of weighting of observations. It is shown that this approach leads to a successful assimilation technique that reduced the RMS difference between the model and the data from 16 cm to 5 cm during one year of assimilation. The ocean model returns an optimized mean dynamic ocean topography. The effects of assimilation on transport estimates across several hydrographic World Ocean Circulation Experiment (WOCE) sections show improvements compared to the FEOM run without data assimilation. As a result of the assimilation, DOT estimates are available in the polar or coastal regions where the geodetic estimates from satellite data alone are not adequate. Furthermore, more realistic features of the ocean can be seen in these areas compared to those obtained using the filtered data fields. 相似文献
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Collinear and cross-over adjustment of Geosat ERM and Seasat altimeter data in the Mediterranean Sea 总被引：1，自引：0，他引：1
The computation of mean sea surface heights from a set of collinear Geosat ERM altimeter data tracks was carried out in a collinear adjustment, where 1 cy/rev cosine and sine coefficients for each track are estimated, so the differences between the collinear tracks are minimized. Then bias/tilt cross-over adjustments of stacked Geosat and Seasat altimetry were carried out. The problems with the free surface in the cross-over adjusted altimetric surface were treated using the absolute sea surface heights relative to the geoid model OSU89B. In a combined adjustment of the two altimeter data sets using cross-over and height informations simultaneously a RMS of the cross-overs of 0.080 m and a RMS of the sea surface heights relative to OSU89B of 0.611 m were obtained. 相似文献
16.
对ＧＥＯＳＡＴ测高卫星在中国近海区域（０°－３５°Ｎ,１０５°－１２７°Ｅ）以及１２７°－１３５°Ｅ内６个ＥＲＭ周期（１９８７年１月１日－４月１２日）的地球物理数据记录（ＧＤＲ）中的数据进行了编辑和预处理．根据卫星弧段的实际长度选取了混合轨道误差模型,并采用最小二乘技术对上升弧段与下降弧段交叠点处的不符值进行了平差计算．处理结果表明,所选用的方法可以大大地消除径向轨道误差的影响,使交叠点处的不符值由原来的５６ｃｍ（ＲＭＳ）降低到现在的２４ｃｍ（ＲＭＳ）在此基础上,构造出６个１°×１°的中国近海海平面及其平均海平面．该平面被称为＂测高大地水准面＂与美国Ｏｈｉｏ州立大学的ＯＳＵ９１Ａ重力场模型的大地水准面相比,两者具有同等量级的精度及一致的形态。 相似文献
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由于卫星观测技术的发展，现在已能利用测高大地水准面简捷可靠地研究海底构造与动力问题. 根据Geosat T2/ERM、Topex/Poseidon 和ERS 1/2测高数据给定的0°N ～45°N、100°E～150°E范围内4′×4′大地水准面，采用全球地形/均衡的重力位效应改正，计算布格、格莱尼和均衡大地水准面. 由格莱尼大地水准面反演Moho面埋深，再从均衡大地水准面起伏推算小尺度地幔流应力场. 结果表明，菲律宾海和南海显示了与磁条带、扩张脊对应或斜交的高频成分大地水准面起伏条带. 各边缘海盆的Moho面埋深有往南变浅的趋势，与菲律宾海各海盆的Moho面埋深大致相当，说明琉球—台湾—菲律宾岛弧两侧的构造动力强度基本相近. 从各种构造特征和大、中、小尺度的地幔流应力场的驱动机制，可以证明岛弧内侧的边缘海具有不同于大洋、大陆的独特构造动力格局和特征. 相似文献