Terrestrial water storage variations and their effect on polar motion

Śliwińska, Justyna; Wińska, Małgorzata; Nastula, Jolanta

doi:10.1007/s11600-018-0227-x

Cited by 19 publications

(25 citation statements)

References 75 publications

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“…In this study, the reference series are GAO and the evaluated series are GSMAM, GRACE + SLR and HAM + SLAM. There is a better consistency of GSMAM series with GAO for the case of χ 2 component, which has been already reported in previous research (e.g., [7,12,[15][16][17]30,55]), and is tightly related to the continent-ocean distribution. The values given in Table 1 reveal that CSR RL06, ITSG 2018 and CNES RL04 solutions provide the highest correlation coefficients with GAO and the most satisfactory relative explained variance values for both χ 1 and χ 2 .…”

Section: Overall Comparison Of Gsmam Seriessupporting

confidence: 82%

“…The role of atmospheric and oceanic mass distribution on the global balance of Earth's angular momentum, described as atmospheric and oceanic angular momentum (AAM and OAM, respectively), is well established [7][8][9][10][11][12][13]. However, the role of the continental hydrosphere, referred to as hydrological angular momentum (HAM) or the hydrological excitation, is less clear as indications from different hydrological models do not agree well with each other [14][15][16][17][18]. Moreover, other geophysical effects, such as the consequences of co-and post-seismic deformations associated with large earthquakes [19], and the coupling between the Earth's core and the lower mantle [20,21], are often not considered in a rigorous way.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating Gravimetric Polar Motion Excitation Estimates from the RL06 GRACE Monthly-Mean Gravity Field Models

et al. 2020

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Over the last 15 years, the Gravity Recovery and Climate Experiment (GRACE) mission has provided measurements of temporal changes in mass redistribution at and within the Earth that affect polar motion. The newest generation of GRACE temporal models, are evaluated by conversion into the equatorial components of hydrological polar motion excitation and compared with the residuals of observed polar motion excitation derived from geodetic measurements of the pole coordinates. We analyze temporal variations of hydrological excitation series and decompose them into linear trends and seasonal and non-seasonal changes, with a particular focus on the spectral bands with periods of 1000–3000, 450–1000, 100–450, and 60–100 days. Hydrological and reduced geodetic excitation series are also analyzed in four separated time periods which are characterized by different accuracy of GRACE measurements. The level of agreement between hydrological and reduced geodetic excitation depends on the frequency band considered and is highest for interannual changes with periods of 1000–3000 days. We find that the CSR RL06, ITSG 2018 and CNES RL04 GRACE solutions provide the best agreement with reduced geodetic excitation for most of the oscillations investigated.

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Section: Overall Comparison Of Gsmam Seriessupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Evaluating Gravimetric Polar Motion Excitation Estimates from the RL06 GRACE Monthly-Mean Gravity Field Models

et al. 2020

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“…The correlations between seasonal GAO and seasonal HAM from ITSG 2018 did not depend on the time period considered (Figure 3). Similar to amplitude and phase agreement shown in Figures 1 and 2 and results shown in previous works [26,[28][29][30]32,37,55], visibly better correlations were obtained for χ 2 . This was also observed for almost all hl-SST solutions.…”

Section: Seasonal Variationssupporting

confidence: 91%

“…Notably, the newest solutions from ITSG (GRACE AB ITSG v3 and Combined v3) visibly overestimated amplitudes of GAO in χ 2 , whereas GRACE AB CAS underestimated amplitudes of GAO in χ 2 . In general, better phase agreement with GAO was obtained for χ 2 component and this was also observed in previous works, e.g., in References [26,[28][29][30]32,37,55]. This resulted from spatial distribution of land and ocean that determine χ 2 to be more sensitive to mass changes over land, and χ 1 to be more sensitive to mass changes over ocean, ice, and glaciers.…”

Section: Seasonal Variationssupporting

confidence: 84%

“…2019, 11, 1784 4 of 19 to quantify mass-related PM excitation. The GRACE monthly solutions, based on precise range-rate measurements between two satellites (ll-SST), have been widely used for this purpose following extensive research in recent years [25][26][27][28][29][30][31]. Special interest has been placed on HAM, as AAM and OAM are well established [32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

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Determining and Evaluating the Hydrological Signal in Polar Motion Excitation from Gravity Field Models Obtained from Kinematic Orbits of LEO Satellites

Śliwińska

Nastula

2019

Remote Sensing

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This study evaluates the gravity field solutions based on high-low satellite-to-satellite tracking (hl-SST) of low-Earth-orbit (LEO) satellites: GRACE, Swarm, TerraSAR-X, TanDEM-X, MetOp-A, MetOp-B, and Jason 2, by converting them into hydrological polar motion excitation functions (or hydrological angular momentum (HAM)). The resulting HAM series are compared with the residuals of observed polar motion excitation (geodetic residuals, GAO) derived from precise geodetic measurements, and the HAM obtained from the GRACE ITSG 2018 solution. The findings indicate a large impact of orbital altitude and inclination on the accuracy of derived HAM. The HAM series obtained from Swarm data are found to be the most consistent with GAO. Visible differences are found in HAM obtained from GRACE and Swarm orbits and provided by different processing centres. The main reasons for such differences are likely to be different processing approaches and background models. The findings of this study provide important information on alternative data sets that may be used to provide continuous polar motion excitation observations, of which the Swarm solution provided by the Astronomical Institute, Czech Academy of Sciences, is the most accurate. However, further analysis is needed to determine which processing algorithms are most appropriate to obtain the best correspondence with GAO.

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Assessing the impact of corrections included in the GRACE Level-3 data on gravimetric polar motion excitation estimates

Śliwińska

Nastula

2023

J Geod

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Between 2002 and 2017, the Gravity Recovery and Climate Experiment (GRACE) mission provided datasets of temporal variations of the Earth’s gravity field, among others in the form of maps of terrestrial water storage (TWS) changes (Level-3 datasets). This paper examines the impact of several corrections included in the GRACE Level-3 data on the estimated series of hydrological plus cryospheric angular momentum (HAM/CAM). We tested the role of removing the glacial isostatic adjustment (GIA) signal, adding degree-1 coefficients of geopotential (DEG1 correction), replacing the degree-2 zonal coefficient with a more accurate estimate from satellite laser ranging (C20 correction), and restoring ocean bottom pressure geopotential coefficients (GAD). The contribution of improved separation of land and ocean signals by using the Coastal Resolution Improvement (CRI) filter was also assessed. We examined the change in agreement between HAM/CAM and the hydrological plus cryospheric signal in geodetically observed excitation (geodetic residuals, GAO) when the corrections are applied. The results show that including GIA, DEG1, C20, and GAD corrections in the GRACE data increases HAM/CAM trends and reduces overall HAM/CAM variability. The exploitation of corrections slightly heightens consistency between HAM/CAM and GAO for χ1 and χ2 in the non-seasonal spectral band and for χ1 in the seasonal spectral band. The results from this study demonstrate how the different corrections combine to make the overall improvement in agreement between HAM/CAM and GAO and which corrections are most valuable.

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Terrestrial water storage variations and their effect on polar motion

Cited by 19 publications

References 75 publications

Evaluating Gravimetric Polar Motion Excitation Estimates from the RL06 GRACE Monthly-Mean Gravity Field Models

Evaluating Gravimetric Polar Motion Excitation Estimates from the RL06 GRACE Monthly-Mean Gravity Field Models

Determining and Evaluating the Hydrological Signal in Polar Motion Excitation from Gravity Field Models Obtained from Kinematic Orbits of LEO Satellites

Assessing the impact of corrections included in the GRACE Level-3 data on gravimetric polar motion excitation estimates

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