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基于卷积神经网络预测南海海底地形

大地测量与地球动力学 2024年第3期44卷 287-292页

作者：王怀兵万晓云 Richard Fiifi Annan 中国地质大学(北京)土地科学技术学院北京市100083

针对南海区域,使用3种重力信号(垂线偏差、重力异常、垂直重力梯度异常)训练卷积神经网络模型,并将预测结果与船测数据和国外模型结果进行对比分析。将3种重力信号分成4组数据:重力异常,重力异常与垂直重力梯度异常,重力异常与垂线偏差... 详细信息

针对南海区域,使用3种重力信号(垂线偏差、重力异常、垂直重力梯度异常)训练卷积神经网络模型,并将预测结果与船测数据和国外模型结果进行对比分析。将3种重力信号分成4组数据:重力异常,重力异常与垂直重力梯度异常,重力异常与垂线偏差,以及重力异常、垂线偏差和垂直重力梯度异常。4种组合方式的反演结果与船测水深之间的标准差分别为104.780 m、102.778 m、93.788 m、88.289 m,表明随着不同类型重力数据的加入,水深预测精度明显提高,并且在深度大于2000 m时,反演结果精度提升效果更为显著。将训练集占总数据集的比例分别设置为80%、70%、60%和50%,反演结果与船测水深之间的标准差分别为88.289 m、91.256 m、92.833 m、96.022 m,表明数据量的增多可以有效提高模型学习结果的精度。

关键词：卷积神经网络重力场信息深度学习海底地形频域法

Recovery of the gravity field from GOCE data by using the invariants of gradient tensor

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Science China Earth Sciences 2013年第9期56卷 1193-1199页

作者： YU JinHai wan xiaoyun Key Laboratory of Computational Geodynamics Chinese Academy of Sciences College of Earth Science Graduate University of Chinese Academy of Sciences

The gravity field models GUCAS_EGM and GUCAS_EGM_DL are established from GOCE data (GOCE Level 2 Products from Nov. 1 to Dec. 31, 2009) based on the method of the invariants of the gravity gradient tensor, where GUCAS_EGM is derived after GOCE gravity gradient data are filtered with FIR, and GUCAS_EGM_DL is computed with an additional Durbin-Levison arithmetic apart from FIR. Since this method, different from current programs dealing with GOCE data, is introduced for the first time, some new problems are required to be discussed in advance; for example, how to filter GOCE gravity gradient data, how to compute the invariants of the gradient tensor, and how to deal with the pole gap and so on. In addition, by comparing our models with ones recommended by ESA, it can be seen that the variations of GUCAS_EGM and the models recommended by ESA to EGM08 are almost equivalent, and the variation of GUCAS_EGM_DL to EGM08 is obviously less than ones of the recommended models.

关键词： GOCE invariants of gravity tensor gravity field model

Bathymetry inversion using the deflection of the vertical:A case study in South China Sea

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Geodesy and Geodynamics 2022年第5期13卷 492-502页

作者： xiaoyun wan Bo Liu Xiaohong Sui Richard F.Annan Ruijie Hao Yijun Min School of Land Science and Technology China University of Geosciences(Beijing)Beijing 100083China Qian Xuesen Laboratory of Space Technology Beijing 100094China

The deflection of the vertical is one of the essential products of ***,unlike gravity and vertical gravity gradients,it is seldom used in bathymetry *** this study,an algorithm for bathymetry inversion using the deflection of the vertical is ***,we separately derive the formulas for the bathymetry inversion from the north and east components of the vertical deflection and introduce the data *** a local area in the South China Sea is selected as an example to test the *** bathymetry inversion based on gravity anomaly is also conducted for *** the ship-borne depths are the true values,the error standard deviations(STDs)of the bathymetry derived by north and east components of the vertical deflection are 156.64 m and 165.57 m,*** indicates that the north component has a better performance in bathymetry inversion than the east *** inversion results from the combination of both components show a higher accuracy of bathymetry than that from a single *** difference between the error STD of the combination results and that of the gravity anomaly is less than 0.2 *** experiment’s results also show that the precision of the derived bathymetry can be improved if the parameters of linear regression are adjusted according to water *** summary,among the gravity field products used in this study,the gravity anomaly yielded the best performance in the bathymetry ***,since additional data and computation time are required to derive gravity anomalies from altimetric observations,the vertical defections can still be used as supplements,especially in areas where accurate vertical deflections exist.

关键词： Bathymetry Deflection of the vertical Gravity anomaly Satellite altimetry

An Expression for Gravity Generated by an Anomalous Geological Body and Its Application in Bathymetry Inversion

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Journal of Geodesy and Geoinformation Science 2021年第4期4卷 63-73页

作者： Huan XU Jinhai YU xiaoyun wan Lei LIANG College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China School of Land Science and Technology China University of Geosciences(Beijing)Beijing 100083China Innovation Academy for Precision Measurement Science and Technology Chinese Academy of SciencesWuhan 430077China

The gravity anomaly and vertical gravity gradient due to anomalous geological bodies are mainly computed by numerical methods,so it is difficult and time-consuming to use the gravity-geological method to invert seafloor *** paper addresses this issue by deriving an expression for gravity generated by a cylinder based on a series *** choice of number for terms in the series is estimated by comparing with the numerical method,especially when the depth H=4000m,the accuracy of 1 mGal(1 Gal=10^(-2)m/s^(2))can be achieved when the series are *** expressions can be used to establish the relationships between the shape of an anomalous body and the generated vertical gravity and vertical gravity gradient,***,the potential applications of the expressions in inverting seafloor topography are illustrated by synthetic examples.

关键词： gravity-geological method anomalous geological body vertical gravity anomaly vertical gravity gradient anomaly

Analysis of limitations on recovery of gravity field based on satellite gravity gradient data

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Geodesy and Geodynamics 2021年第1期12卷 31-42页

作者： xiaoyun wan Jinhai Yu Lei Liang Jiangjun Ran Richard Fiifi Annan School of Land Science and Technology China University of Geosciences(Beijing)Beijing100089China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of Geodesy and Earth's Dynamics Institute of Geodesy and Geophysics Chinese Academy of SciencesWuhan430077China Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen518055China

Although satellite gravity gradient data plays a great role in determining short-wavelength part of static gravity field model,accuracy of the long-wavelength part of gravity field model recovered by them are poor,which leads to only a few applications in time-variable gravity *** reason is that some factors limit the accuracy of the gravity field recovered using gradient data,including accuracy of the gravity gradient observations,measurement bandwidth(MBW)of gradiometer,satellite inclination,*** paper aims at analyzing the influence of these limitations on gravity field recovery and discusses the possibility of time-variable gravity field detection by using gravity gradient ***,for arbitrary satellite orbit inclination,we give the frequency distributions of all the components of gravity gradients(***;Tyy;Tzz;Txy;Txz and Tyz,).The results show that the maximum frequency of each component of the gravity gradients is the same,i.e.l=Ts(l is degree of the gravity field model,Ts is the orbital periods),and it is not influenced by the inclination of the satellite ***,the paper gives a theory proof to explain why only the low orders of the coefficients are influenced by polar *** polar gaps are experimented by a numerical test with inclination of 45°.Finally,considering that the measurement bandwidth can be expanded and accuracy of gradient observations can be improved by superconducting gravity gradiometer(SGG)compared to gradiometer used in Gravity field and steadystate Ocean Circulation Explorer(GOCE),the possibility of detecting time-variable gravity using gravity gradient observations is *** results show that the SGG creates errors in MBW with magnitude of 0.014 m E,which is smaller than the magnitude of the time-variable gravity gradient signals(i.e.,0.02 m E)derived from Gravity Recovery and Climate Experiment(GRACE)gravity field *** indicates the potential of SGG in time-variable gravity de

关键词： Gravity gradients Gradiometer measurement bandwidth Frequency analysis Polar gaps Time-variable gravity field

Sea surface height measuring using InSAR altimeter

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Geodesy and Geodynamics 2017年第4期8卷 278-284页

作者： Xiaohong Sui Running Zhang Falin Wu Yang Li xiaoyun wan DFH Satellite Co. Ltd Beijing 100094 China Qian Xuesen Laboratory of Space Technology Beijing 100094 China Beijing Institute of Spacecraft System Engineering Beijing 100094 China Beihang University Beijing 100083 China

Satellite altimetry has been widely used in measuring ocean topography from space. The conventional altimeter system is the nadir radar altimeter system which has the limitations of one-dimensional measurement and is unable to get both high temporal and spatial resolution. The InSAR altimetry system using InSAR altimeter instead of nadir radar altimeter is an improvement which can get both high cross-track and along-track resolution and wide swath. However, the conventional SAR interferometry only can achieve meter level height accuracy. This paper focuses on a method of radar echo-tracking for InSAR altimeter system in order to correct the slant range measurements and finally to improve the height measurement accuracy to several centimeters＇ level. Radar slant range （from observed pixels to radar antenna） estimation error affects the height measurement accuracy badly, nevertheless not considered in the conventional SAR interferometry. The proposed method is ameliorated based on the traditional echo-model used in nadir radar altimeter system, focusing on the echo signals from observed pixels with different incident angles. Simulations of sea surface height measurements are performed in the last part of this paper, and the conclusions are drawn that, with corrected slant range, the accuracy of InSAR altimetry can be much better than the conventional SAR interferometry.

关键词： InSAR altimeter Nadir radar altimeter Sea surface height Echo-tracking

GRACE observed mass loss in the middle and lower Yangtze basin

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Geodesy and Geodynamics 2019年第2期10卷 157-162页

作者： Jiangjun Ran Natthachet Tangdamrongsub Junchao Shi Changqing wang Lihui wang xiaoyun wan Institute of Geodesy and Geophysics Chinese Academy of Sciences School of Engineering University of Newcastle Information Center Ministry of Water Resources Qian Xuesen Laboratory of Space Technology

Anthropogenic architectures have a significant impact to the environment. The Three Gorges Dam(TGD),as the largest dam in the world, is a typical example, and has influenced the mass anomalies transported by the flow downstream in the Yangtze River since June 2003. However, the evidence of TGD influence on downstream mass transportation is not documented. In this study, we analyze the monthly gravity solutions from GRACE to investigate the downstream mass variations of Yangtze River. From our results,the considerable mass loss is detected in the downstream of TGD. By comparing our estimations with the in situ water level data of TGD, we find that the mass variations derived from GRACE at Datong station decreases shortly after the impoundment of TGD. This confirms a strong connection between ***, by comparing with the in situ sediment load and river discharge at Yichang and Datong gauging stations, we find that the sediment load data shows a similar mass loss signature while the river discharge of both stations has stay at a relative stable level. This indicates that further study is still needed to understand the mechanism better.

关键词： GRACE Mass loss The Yangtze River basin Sediment load River discharge

Education Research on Children's Art from the Perspective of Psychology

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Education Research on Children's Art from the Perspective of...

Research on Calligraphy Teaching of Primary School Students from the Perspective of Psychology

3rd International Conference on Culture, Education and Economic Development of Modern Society (ICCESE 2019)

作者： xiaoyun wan Leshan Normal University

Education activity of children's art is an important means for children to know themselves and the world, and a bridge connecting children with the outside world. Education activity of children's art and children's physical and mental development benefit and promote each other in the two-way construction. Children need art education, and appropriate art education activities will promote the harmonious development of children's physical and mental health.

关键词： children art psychology aesthetic ability emotional expression

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Research on Calligraphy Teaching of Primary School Students ...