Journal of Geodetic Science最新文献_第9页

Optimal mathematical and statistical models to estimate vertical crustal movements using satellite altimetry and tide gauge data 利用卫星测高和测潮数据估计地壳垂直运动的最佳数学和统计模型

IF 1.3

Journal of Geodetic Science Pub Date : 2019-01-01 DOI: 10.1515/jogs-2019-0014

H. Iz, T. Y. Yang, C. Shum, C. Kuo

{"title":"Optimal mathematical and statistical models to estimate vertical crustal movements using satellite altimetry and tide gauge data","authors":"H. Iz, T. Y. Yang, C. Shum, C. Kuo","doi":"10.1515/jogs-2019-0014","DOIUrl":"https://doi.org/10.1515/jogs-2019-0014","url":null,"abstract":"Abstract Knowledge of vertical crustal movement is fundamental to quantify absolute sea level changes at tide gauge locations as well as for satellite altimetry calibration validations. While GPS measurements at collocated tide gauge stations fulfill this need, currently only few hundred tide gauge stations are equipped with GPS, and their measurements do not span a long period of time. In the past, several studies addressed this problem by calculating relative and geocentric trends from the tide gauge and satellite altimetry measurements respectively, and then difference the two trends to calculate the rate of changes at the tide gauge stations. However, this approach is suboptimal. This study offers an optimal statistical protocol based on the method of condition equations with unknown parameters. An example solution demonstrates the proposed mathematical and statistical models’ optimality in estimating vertical crustal movement and its standard error by comparing them with the results of current methods. The proposed model accounts for the effect of autocorrelations in observed tide gauge and satellite altimetry sea level time series, adjusts observed corrections such as inverted barometer effects, and constraints tide gauge and satellite altimeter measurement to close. The new model can accommodate estimating other systematic effects such as pole tides that are not eliminated by differencing.","PeriodicalId":44569,"journal":{"name":"Journal of Geodetic Science","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84611530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Evaluation of Gravity Data Derived from Global Gravity Field Models Using Terrestrial Gravity Data in Enugu State, Nigeria 利用尼日利亚埃努古州陆地重力数据评估全球重力场模型得出的重力数据

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0015

O. I. Apeh, E. C. Moka, V. Uzodinma

{"title":"Evaluation of Gravity Data Derived from Global Gravity Field Models Using Terrestrial Gravity Data in Enugu State, Nigeria","authors":"O. I. Apeh, E. C. Moka, V. Uzodinma","doi":"10.1515/jogs-2018-0015","DOIUrl":"https://doi.org/10.1515/jogs-2018-0015","url":null,"abstract":"Abstract Spherical harmonic expansion is a commonly applied mathematical representation of the earth’s gravity field. This representation is implied by the potential coeffcients determined by using elements/parameters of the field observed on the surface of the earth and/or in space outside the earth in the spherical harmonic expansion of the field. International Centre for Gravity Earth Models (ICGEM) publishes, from time to time, Global Gravity Field Models (GGMs) that have been developed. These GGMs need evaluation with terrestrial data of different locations to ascertain their accuracy for application in those locations. In this study, Bouguer gravity anomalies derived from a total of eleven (11) recent GGMs, using sixty sample points, were evaluated by means of Root-Mean-Square difference and correlation coeficient. The Root-Mean-Square differences of the computed Bouguer anomalies from ICGEMwebsite compared to their positionally corresponding terrestrial Bouguer anomalies range from 9.530mgal to 37.113mgal. Additionally, the correlation coe_cients of the structure of the signal of the terrestrial and GGM-derived Bouguer anomalies range from 0.480 to 0.879. It was observed that GECO derived Bouguer gravity anomalies have the best signal structure relationship with the terrestrial data than the other ten GGMs. We also discovered that EIGEN-6C4 and GECO derived Bouguer anomalies have enormous potential to be used as supplements to the terrestrial Bouguer anomalies for Enugu State, Nigeria.","PeriodicalId":44569,"journal":{"name":"Journal of Geodetic Science","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85148800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Optimal biased Kriging: Homeogram tapering and applications to geoid undulations in Korea 最优偏置克里格:韩国大地水准面波动的同形图锥形和应用

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0016

B. Schaffrin, T. Bae, Y. Felus

引用次数: 0

Why and how to predict sea level changes at a tide gauge station with prediction intervals 为何及如何在潮汐测量站以预测间隔预测海平面变化

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0012

H. Iz

引用次数: 7

On the geoid and orthometric height vs. quasigeoid and normal height 关于大地水准面和正交高度vs.拟大地水准面和法线高度

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0011

L. Sjöberg

{"title":"On the geoid and orthometric height vs. quasigeoid and normal height","authors":"L. Sjöberg","doi":"10.1515/jogs-2018-0011","DOIUrl":"https://doi.org/10.1515/jogs-2018-0011","url":null,"abstract":"Abstract The geoid, but not the quasigeoid, is an equipotential surface in the Earth’s gravity field that can serve both as a geodetic datum and a reference surface in geophysics. It is also a natural zero-level surface, as it agrees with the undisturbed mean sea level. Orthometric heights are physical heights above the geoid,while normal heights are geometric heights (of the telluroid) above the reference ellipsoid. Normal heights and the quasigeoid can be determined without any information on the Earth’s topographic density distribution, which is not the case for orthometric heights and geoid. We show from various derivations that the difference between the geoid and the quasigeoid heights, being of the order of 5 m, can be expressed by the simple Bouguer gravity anomaly as the only term that includes the topographic density distribution. This implies that recent formulas, including the refined Bouguer anomaly and a difference between topographic gravity potentials, do not necessarily improve the result. Intuitively one may assume that the quasigeoid, closely related with the Earth’s surface, is rougher than the geoid. For numerical studies the topography is usually divided into blocks of mean elevations, excluding the problem with a non-star shaped Earth. In this case the smoothness of both types of geoid models are affected by the slope of the terrain,which shows that even at high resolutions with ultra-small blocks the geoid model is likely as rough as the quasigeoid model. In case of the real Earth there are areas where the quasigeoid, but not the geoid, is ambiguous, and this problem increases with the numerical resolution of the requested solution. These ambiguities affect also normal and orthometric heights. However, this problem can be solved by using the mean quasigeoid model defined by using average topographic heights at any requested resolution. An exact solution of the ambiguity for the normal height/quasigeoid can be provided by GNSS-levelling.","PeriodicalId":44569,"journal":{"name":"Journal of Geodetic Science","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90977748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Assessment of sparse GNSS network for network RTK 稀疏GNSS网络的网络RTK评价

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0014

H. Koivula, J. Kuokkanen, Simo Marila, S. Lahtinen, Tuukka Mattila

引用次数: 4

Sea level accelerations at globally distributed tide gauge stations during the satellite altimetry era 卫星测高时代全球分布的潮汐计站的海平面加速度

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0013

H. Iz, C. Shum, C. Kuo

引用次数: 12

Fast computation of sine/cosine series coefficients of associated Legendre function of arbitrary high degree and order 快速计算任意高阶相关勒让德函数的正弦/余弦级数系数

IF 1.3

Journal of Geodetic Science Pub Date : 2018-12-01 DOI: 10.1515/jogs-2018-0017

T. Fukushima

引用次数: 1

Geodesic equations and their numerical solution in Cartesian coordinates on a triaxial ellipsoid 三轴椭球上直角坐标系下的测地线方程及其数值解

IF 1.3

Journal of Geodetic Science Pub Date : 2018-11-08 DOI: 10.1515/jogs-2019-0001

G. Panou, R. Korakitis

引用次数: 9

The changing mass of glaciers on the Tibetan Plateau, 2002–2016, using time-variable gravity from the GRACE satellite mission 2002-2016年青藏高原冰川质量变化，使用GRACE卫星任务的时变重力

IF 1.3

Journal of Geodetic Science Pub Date : 2018-11-01 DOI: 10.1515/jogs-2018-0010

Alyson K. Beveridge, C. Harig, F. Simons

{"title":"The changing mass of glaciers on the Tibetan Plateau, 2002–2016, using time-variable gravity from the GRACE satellite mission","authors":"Alyson K. Beveridge, C. Harig, F. Simons","doi":"10.1515/jogs-2018-0010","DOIUrl":"https://doi.org/10.1515/jogs-2018-0010","url":null,"abstract":"Abstract The Tibetan Plateau is the largest region of high elevation in the world. The source of water for a number of important rivers, the Himalayan region is vital to the billions of inhabitants of the Asian continent. Over the last fifty years, the climate in the region has warmed more rapidly than anywhere else at the same latitude. Causes and effects, and the geographical details of these alarming warming trends are as yet not fully known. One way of assessing the effects of climate change in this area is to measure the change in glacier volume in the region, but estimates made on the basis of different techniques have not been conclusive to date, and remain difficult to reconcile. We examine the temporal behavior of the mass flux integrated over four distinct groupings of Tibetan glaciers using satellite gravimetry from the Gravity Recovery and Climate Experiment (GRACE). We use a technique known as spatio-spectral localization using spherical Slepian functions to convert global spherical harmonic expansions of the time-dependent geopotential into monthly estimates of mass changes over the Tibetan Plateau. Subsequent reductions are aimed at interpreting this mass change as due to gains or losses in ice mass. We find that (ice) mass has been decreasing on the Tibetan Plateau between 2002 and 2016 but with significant spatial variability throughout the region. Specifically, in the regions of Himalaya, Pamir, Qilian, and Tien Shan, glaciers have been losing ice mass at a rate of −11±3, −1±2, +8±2, and −6±1 Gt/yr, respectively, over the last decade.","PeriodicalId":44569,"journal":{"name":"Journal of Geodetic Science","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88096122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5