Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan
We investigated the Fourier transform-based downward continuation (DWC) of airborne gravity anomalies around Taiwan assisted by topographic information. The topographic data are from the latest collections of elevations and ocean depths. The DWC employs a remove-compute-restore (RCR) procedure in wh...
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2010-01-01
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doaj-cc3b420082ca4ada9dc9a3955289564f2020-11-25T00:20:30ZengChinese Geoscience UnionTerrestrial, Atmospheric and Oceanic Sciences1017-08392311-76802010-01-0121461510.3319/TAO.2009.07.09.01(T)938Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in TaiwanYu-Shen Hsiao Cheinway HwangWe investigated the Fourier transform-based downward continuation (DWC) of airborne gravity anomalies around Taiwan assisted by topographic information. The topographic data are from the latest collections of elevations and ocean depths. The DWC employs a remove-compute-restore (RCR) procedure in which the topography is removed prior to computation and then restored to achieve stable solutions. The topographic gravity effect is evaluated point-wise using the Gaussian quadrature. A Gaussian filter with an optimal smoothing parameter reduces the noise-amplifying effect of DWC. Use of topography in DWC leads to improvements of 3 to 6 mgal of gravity on land. Surface and downward continued gravity anomalies are used to determine geoidal heights by least squares collocation (LSC) in a similar RCR procedure through the same topographic data. The accuracy of the geoidal heights at Taiwan¡¦s first-order leveling benchmarks is improved by 1 to 2 cm due to inclusion of downward continued airborne gravity. http://tao.cgu.org.tw/images/attachments/v213p615.pdf GeoidDownward continuationGravity anomalyLeast-squares collocationTopography |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yu-Shen Hsiao Cheinway Hwang |
spellingShingle |
Yu-Shen Hsiao Cheinway Hwang Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan Terrestrial, Atmospheric and Oceanic Sciences Geoid Downward continuation Gravity anomaly Least-squares collocation Topography |
author_facet |
Yu-Shen Hsiao Cheinway Hwang |
author_sort |
Yu-Shen Hsiao Cheinway Hwang |
title |
Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan |
title_short |
Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan |
title_full |
Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan |
title_fullStr |
Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan |
title_full_unstemmed |
Topography-Assisted downward Continuation of Airborne Gravity: An Application for Geoid Determination in Taiwan |
title_sort |
topography-assisted downward continuation of airborne gravity: an application for geoid determination in taiwan |
publisher |
Chinese Geoscience Union |
series |
Terrestrial, Atmospheric and Oceanic Sciences |
issn |
1017-0839 2311-7680 |
publishDate |
2010-01-01 |
description |
We investigated the Fourier transform-based downward continuation (DWC) of airborne gravity anomalies around Taiwan assisted by topographic information. The topographic data are from the latest collections of elevations and ocean depths. The DWC employs a remove-compute-restore (RCR) procedure in which the topography is removed prior to computation and then restored to achieve stable solutions. The topographic gravity effect is evaluated point-wise using the Gaussian quadrature. A Gaussian filter with an optimal smoothing parameter reduces the noise-amplifying effect of DWC. Use of topography in DWC leads to improvements of 3 to 6 mgal of gravity on land. Surface and downward continued gravity anomalies are used to determine geoidal heights by least squares collocation (LSC) in a similar RCR procedure through the same topographic data. The accuracy of the geoidal heights at Taiwan¡¦s first-order leveling benchmarks is improved by 1 to 2 cm due to inclusion of downward continued airborne gravity. |
topic |
Geoid Downward continuation Gravity anomaly Least-squares collocation Topography |
url |
http://tao.cgu.org.tw/images/attachments/v213p615.pdf
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work_keys_str_mv |
AT yushenhsiaocheinwayhwang topographyassisteddownwardcontinuationofairbornegravityanapplicationforgeoiddeterminationintaiwan |
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1725367157633581056 |