Study on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models

Lenczuk, Artur; Leszczuk, Grzegorz; Kłos, Anna; Kosek, W.; Bogusz, Janusz

doi:10.1515/jag-2020-0017

Cited by 10 publications

(7 citation statements)

References 48 publications

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“…For GLDAS, values up to 5 cm are noted for northern Europe and Asia, and may be caused by seasonal water changes in high latitudes, which are overestimated in the GLDAS hydrological model [44]; this was already presented by [45] for vertical displacements caused by TWS. For WGHM, the amplitude differences are significant additionally for the equator regions (Central Africa, Southern Asia), where we obtained values in the 10-15 cm range.…”

Section: Comparison Of Tws Changes Between Grace/-fo and Hydrological...mentioning

confidence: 94%

Autoregressive Reconstruction of Total Water Storage within GRACE and GRACE Follow-On Gap Period

et al. 2022

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For 15 years, the Gravity Recovery and Climate Experiment (GRACE) mission have monitored total water storage (TWS) changes. The GRACE mission ended in October 2017, and 11 months later, the GRACE Follow-On (GRACE-FO) mission was launched in May 2018. Bridging the gap between both missions is essential to obtain continuous mass changes. To fill the gap, we propose a new approach based on a remove–restore technique combined with an autoregressive (AR) prediction. We first make use of the Global Land Data Assimilation System (GLDAS) hydrological model to remove climatology from GRACE/GRACE-FO data. Since the GLDAS mis-models real TWS changes for many regions around the world, we further use least-squares estimation (LSE) to remove remaining residual trends and annual and semi-annual oscillations. The missing 11 months of TWS values are then predicted forward and backward with an AR model. For the forward approach, we use the GRACE TWS values before the gap; for the backward approach, we use the GRACE-FO TWS values after the gap. The efficiency of forward–backward AR prediction is examined for the artificial gap of 11 months that we create in the GRACE TWS changes for the July 2008 to May 2009 period. We obtain average differences between predicted and observed GRACE values of at maximum 5 cm for 80% of areas, with the extreme values observed for the Amazon, Alaska, and South and Northern Asia. We demonstrate that forward–backward AR prediction is better than the standalone GLDAS hydrological model for more than 75% of continental areas. For the natural gap (July 2017–May 2018), the misclosures in backward–forward prediction estimated between forward- and backward-predicted values are equal to 10 cm. This represents an amount of 10–20% of the total TWS signal for 60% of areas. The regional analysis shows that the presented method is able to capture the occurrence of droughts or floods, but does not reflect their magnitudes. Results indicate that the presented remove–restore technique combined with AR prediction can be utilized to reliably predict TWS changes for regional analysis, but the removed climatology must be properly matched to the selected region.

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Section: Comparison Of Tws Changes Between Grace/-fo and Hydrological...mentioning

confidence: 94%

Autoregressive Reconstruction of Total Water Storage within GRACE and GRACE Follow-On Gap Period

et al. 2022

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“…Previous studies compared hydrological models with GRACE gravity field variations but not with this diversity of models and not at these inter‐annual and large spatial scales (Jin & Feng, 2013; Lenczuk et al., 2020; Liu et al., 2019). At inter‐annual and decadal scales, hydrological models compared with GRACE solution are underestimating the hydrological signal on river basins and regarding climate modes (Pfeffer, Cazenave, & Barnoud, 2022; Pfeffer, Cazenave, Blazquez, et al., 2022; Scanlon et al., 2018).…”

Section: Data Presentationmentioning

confidence: 99%

Uncertainty of Low‐Degree Space Gravimetry Observations: Surface Processes Versus Earth's Core Signal

et al. 2023

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Space gravity measurements have been mainly used to study the temporal mass variations at the Earth's surface and within the mantle. Nevertheless, mass variations due to the Earth's core might be observable in the gravity field variations as measured by Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow‐On satellites. Earth's core dynamical processes inferred from geomagnetic field measurements are characterized by large‐scale patterns associated with low spherical harmonic degrees of the potential fields. To study these processes, the use of large spatial and inter‐annual temporal filters is needed. To access gravity variations related to the Earth's core, surface effects must be corrected, including hydrological, oceanic or atmospheric loading (Newtonian attraction and mass redistribution). However, these corrections for surface processes add errors to the estimates of the residual gravity field variations enclosing deep Earth's signals. As our goal is to evaluate the possibility to detect signals of core origin embedded in the residual gravity field variations, a quantification of the uncertainty associated with gravity field products and geophysical models used to minimize the surface process signatures is necessary. Here, we estimate the dispersion for GRACE solutions as about 0.34 cm of equivalent water height (EWH) or 20% of the total signal. Uncertainty for hydrological models is as large as 0.89–2.10 cm of EWH. We provide estimates of Earth's core signals whose amplitudes are compared with GRACE gravity field residuals and uncertainties. The results presented here underline how challenging is to get new information about the dynamics of the Earth's core via high‐resolution, high‐accuracy gravity data.

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“…This contribution is extremely important when accounting for the contribution of freshwater fluxes to the global ocean (Schmied et al, 2020). Previous studies compared hydrological models with GRACE gravity field variations but not with this diversity of models and not at these inter-annual and large spatial scales (Lenczuk et al, 2020;Jin & Feng, 2013;Liu et al, 2019). At inter-annual and decadal scales, hydrological models compared with GRACE solution are underestimating the hydrological signal on river basins and regarding climate modes (Scanlon et al, 2018;Pfeffer et al, 2021Pfeffer et al, , 2022.…”

Section: Hydrologymentioning

confidence: 99%

Uncertainty of low-degree space gravimetry observations: surface processes versus internal signal

Lecomte

Rosat²,

Mandea

et al. 2023

Preprint

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Space gravity measurements have been mainly used to study the temporal mass variations at the Earth’s surface and within the mantle. Nevertheless, mass variations due to the Earth’s core might be observable in the gravity field variations as measured by GRACE(-FO) satellites. Earth’s core dynamical processes inferred from geomagnetic field measurements are characterized by large-scale patterns associated with low spherical harmonic degrees of the potential fields. To study these processes, the use of large spatial and inter-annual temporal filters is needed. To access gravity variations related to the Earth’s core, surface effects must be corrected, including hydrological, oceanic or atmospheric loading (Newtonian attraction and mass redistribution). However, these corrections for surface processes add errors to the estimates of the residual gravity field variations enclosing deep Earth’s signals. As our goal is to evaluate the possibility to detect signals of core origin embedded in the residual gravity field variations, a quantification of the uncertainty associated with gravity field products and geophysical models used to minimise the surface process signatures is necessary. Here, we estimate the dispersion for GRACE solutions as about 0.34 cm of Equivalent Water Height (EWH) or 20% of the total signal. Uncertainty for hydrological models is as large as 0.89 to 2.10 cm of EWH. We provide estimates of Earth’s core signals whose amplitudes are compared with GRACE gravity field residuals and uncertainties. The results presented here underline how challenging is to get new information about the dynamics of the Earth’s core via high-resolution, high-accuracy gravity data.

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Study on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models

Cited by 10 publications

References 48 publications

Autoregressive Reconstruction of Total Water Storage within GRACE and GRACE Follow-On Gap Period

Autoregressive Reconstruction of Total Water Storage within GRACE and GRACE Follow-On Gap Period

Uncertainty of Low‐Degree Space Gravimetry Observations: Surface Processes Versus Earth's Core Signal

Uncertainty of low-degree space gravimetry observations: surface processes versus internal signal

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