On Deflections of Vertical Determined From HY-2A/GM Altimetry Data in the Bay of Bengal

Ji, Hui; Guo, Jinyun; Zhu, Chengcheng; Yuan, Jiajia; Liu, Xin; Li, Guowei

doi:10.1109/jstars.2021.3129273

Cited by 18 publications

(7 citation statements)

References 46 publications

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“…Vening-Meinesz Formula can be used to determine DOVs from gravity anomalies, so inverse of Vening-Meinesz formula is used to derive gravity anomalies from DOVs with the development of altimetry technology (Hwang, 1998;Ji et al, 2021a).…”

Section: Methods Of Deriving Gravity Anomaliesmentioning

confidence: 99%

SDUST2021GRA: Global marine gravity anomaly model recovered from Ka-band and Ku-band satellite altimeter data

Zhu

Guo

Yuan

et al. 2022

Preprint

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Abstract. With the launch of altimetry satellites with different observation frequencies and different survey missions, it is necessary to integrate multi-satellites altimeter data to establish a new global marine gravity anomaly model. Based on Ka-band SSHs from SARAL/AltiKA and Ku-band SSHs from other satellites (including HY-2A) in geodetic missions and exact repeat missions, the global marine gravity anomaly model of SDUST2021GRA on a 1′×1′ grid is derived. Gridded deflections of vertical (DOVs) are determined from along-track geoid gradients by the least-squares collocation method, in which the noise variances of along-track geoid gradients are obtained by the iteration method for Ka-band geodetic mission and by the SSH crossover discrepancies for other altimetry missions. SDUST2021GRA is recovered from the gridded DOVs by the inverse Vening-Meinesz formula, and analyzed by comparing with the recognized marine gravity anomaly models of DTU17 and SIO V30.1. Final, the accuracy of SDUST2021GRA, DTU17 and SIO V30.1 is assessed by preprocessed shipborne gravity anomalies. In conclusion, the differences between SDUST2021GRA and recognized models are small, indicating the reliability of SDUST2021GRA. The differences are mainly concentrated between -5 mGal and 5 mGal, which accounts for more than 95 % of the total number. Assessed by shipborne gravity, the accuracy of SDUST2021GRA is 2.37 mGal in the global, which is higher than that of DTU17 (2.74 mGal) and SIO V30.1(2.69 mGal). The precision advantage of SDUST2021GRA is mainly concentrated in offshore areas. SDUST2021GRA is concluded to reach an international advanced level for the altimeter-derived marine gravity model, especially in the offshore area. The SDUST2021GRA model are freely available at the site of https://doi.org/10.5281/zenodo.6668159 (Zhu et al., 2022).

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Section: Methods Of Deriving Gravity Anomaliesmentioning

confidence: 99%

SDUST2021GRA: Global marine gravity anomaly model recovered from Ka-band and Ku-band satellite altimeter data

Zhu

Guo

Yuan

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Vening Meinesz formula can be used to determine DOVs from gravity anomalies, so the inverse of Vening Meinesz formula is used to derive gravity anomalies from DOVs with the development of altimetry technology (Hwang, 1998;Ji et al, 2021a). Hwang (1998) derived the inverse Vening Meinesz formula and the kernel function based on the spherical harmonic expansion of disturbing potential (Heiskanen and Moritz, 1967), Green's formula (Meissl, 1971), Laplace surface operator (Courant and Hilbert, 1989), orthogonality relationship of fully normalized spherical harmonics (Heiskanen and Moritz, 1967), and the kernel function by Meissl (1971).…”

Section: Methods Of Deriving Gravity Anomaliesmentioning

confidence: 99%

“…Radar altimeter on HY-2A has performed a geodetic mission for about 4 years. HY-2A has proved to play an important role in determining deflections of vertical (DOV) and recovering gravity anomalies (Rapp, 1979;Zhu et al, 2019;Wan et al, 2020;Ji et al, 2021a;Guo et al, 2022). However, HY-2A-measured altimeter data are rarely used for published global models of gravity anomalies.…”

Section: Introductionmentioning

confidence: 99%

SDUST2021GRA: global marine gravity anomaly model recovered from Ka-band and Ku-band satellite altimeter data

Zhu

Guo

Yuan

et al. 2022

Earth Syst. Sci. Data

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Abstract. With the launch of altimetry satellites with different observation frequencies and different survey missions, it is necessary to integrate multi-satellites altimeter data to establish a new global marine gravity anomaly model. Based on Ka-band sea surface heights (SSHs) from SARAL/AltiKA and Ku-band SSHs from other satellites (including HY-2A) in geodetic missions and exact repeat missions, the global marine gravity anomaly model of SDUST2021GRA on a 1′ × 1′ grid is derived. Gridded deflections of vertical (DOV) are determined from along-track geoid gradients by the least squares collocation method, in which the noise variances of along-track geoid gradients are obtained by the iteration method for Ka-band geodetic mission and by the SSH crossover discrepancies for other altimetry missions. SDUST2021GRA is recovered from the gridded DOVs by the inverse Vening Meinesz formula, and analyzed by comparing with the recognized marine gravity anomaly models of DTU17 and SIO V30.1. Finally, the accuracy of SDUST2021GRA, DTU17, and SIO V30.1 is assessed by preprocessed shipborne gravity anomalies. In conclusion, the differences between SDUST2021GRA and recognized models are small, indicating the reliability of SDUST2021GRA. The differences are mainly concentrated between −5 and 5 mGal, which accounts for more than 95 % of the total number. Assessed by shipborne gravity, the accuracy of SDUST2021GRA is 2.37 mGal globally, which is higher than that of DTU17 (2.74 mGal) and SIO V30.1 (2.69 mGal). The precision advantage of SDUST2021GRA is mainly concentrated in offshore areas. HY-2A-measured altimeter data have an important role on gravity anomaly recovery in areas with complex coastlines and many islands. SDUST2021GRA is concluded to reach an international advanced level for the altimeter-derived marine gravity model, especially in the offshore area. The SDUST2021GRA model data are freely available at https://doi.org/10.5281/zenodo.6668159 (Zhu et al., 2022).

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“…The study area is focused on the BOB (80°E-100°E, 0°N-23°N). This region encompasses the largest delta system and basin in the world, resulting in intricate seafloor topography [19], [20]. The location of the study area and its seafloor topography are plotted in Fig.…”

Section: A Study Areasmentioning

confidence: 99%

Validation of Just-Released SWOT L2 KaRIn Beta Prevalidated Data Based on Restore the Marine Gravity Field and Its Application

Guo,

Wan,

Wang

2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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A part of the pre-processed Beta Ka-band Radar Interferometer (KaRIn) data (September 7 -November 21, 2023) for the Surface Water and Ocean Topography (SWOT) mission has been released. To validate the performance of SWOT L2 KaRIn Beta Pre-Validated data (Beta data), this study conducted various experiments, including inverting the ocean gravity field and seafloor topography from these data. Validating the accuracy of deflections of the vertical (DOV) by DOV products of Scripps Institution of Oceanography (SIO). The RMS of differences of north-south and east-west components is about 1.83 urad and 2.71 urad, respectively. The precision of gravity anomaly (SWOT_GA) is about 5.07 mGal compared with shipborne gravity. The results derived from 1-cycle data are comparable to those obtained from a substantial dataset accumulated by traditional nadir altimeters. The accuracy of seafloor topography inverted from SWOT_GA is about 68 m validated by shipborne depth, which is almost the same as the topography obtained from SIO_GA and SDUST2021GRA. The results of multiple experiments have demonstrated that Beta data can be used to compute high-precision ocean gravity fields and seafloor topography products. This proves the success of the first operational run of KaRIn and the capability of SWOT to support studies related to ocean science. The current evaluation results are based on Beta data. The Pre-Validated data will be more accurate after further calibration, which will lead to higher accuracy of the inverted gravitational field products in the future.

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On Deflections of Vertical Determined From HY-2A/GM Altimetry Data in the Bay of Bengal

Cited by 18 publications

References 46 publications

SDUST2021GRA: Global marine gravity anomaly model recovered from Ka-band and Ku-band satellite altimeter data

SDUST2021GRA: Global marine gravity anomaly model recovered from Ka-band and Ku-band satellite altimeter data

SDUST2021GRA: global marine gravity anomaly model recovered from Ka-band and Ku-band satellite altimeter data

Validation of Just-Released SWOT L2 KaRIn Beta Prevalidated Data Based on Restore the Marine Gravity Field and Its Application

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