A mascon approach to assess ice sheet and glacier mass balances and their uncertainties from GRACE data

Schrama, Ernst; Wouters, Bert; Rietbroek, Roelof

doi:10.1002/2013jb010923

Cited by 120 publications

(117 citation statements)

References 69 publications

(132 reference statements)

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“…Leakage error in GRACE estimates can also be reduced by using high-resolution mascon solutions that are derived either directly from GRACE satellite range and range rate measurements (Rowlands et al 2005;Luthcke et al 2013) or from GRACE spherical harmonic solutions (Jacob et al 2012;Schrama et al 2014). Please note that forward modeling can be regarded as a mascon approach using GRACE spherical harmonic solutions and is solved in the spatial domain, as compared to the spherical harmonic domain (e.g., Jacob et al 2012).…”

Section: Uncertainties In Grace Tws Storage Changesmentioning

confidence: 99%

Groundwater Storage Changes: Present Status from GRACE Observations

et al. 2015

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Satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) provide quantitative measurement of terrestrial water storage (TWS) changes with unprecedented accuracy. Combining GRACE-observed TWS changes and independent estimates of water change in soil and snow and surface reservoirs offers a means for estimating groundwater storage change. Since its launch in March 2002, GRACE time-variable gravity data have been successfully used to quantify long-term groundwater storage changes in different regions over the world, including northwest India, the High Plains Aquifer and the Central Valley in the USA, the North China Plain, Middle East, and southern Murray-Darling Basin in Australia, where groundwater storage has been significantly depleted in recent years (or decades). It is difficult to rely on in situ groundwater measurements for accurate quantification of large, regional-scale groundwater storage changes, especially at long timescales due to inadequate spatial and temporal coverage of in situ data and uncertainties in storage coefficients. The now nearly 13 years of GRACE gravity data provide a successful and unique complementary tool for monitoring and measuring groundwater changes on a global and regional basis. Despite the successful applications of GRACE in studying global groundwater storage change, there are still some major challenges limiting the application and interpretation of GRACE data. In this paper, we present an overview of GRACE applications in groundwater studies and discuss if and how the main challenges to using GRACE data can be addressed.

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Section: Uncertainties In Grace Tws Storage Changesmentioning

confidence: 99%

Groundwater Storage Changes: Present Status from GRACE Observations

et al. 2015

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“…We interpolate SMB and D onto a gridded map of EWH with a resolution of 1 • of arc for the GrIS and surrounding areas. To account for leakage from outside the GrIS, as occurs for data products obtained from GRACE, we apply the annual mass change estimates from Schrama et al (2014) for all the major glacier areas (GrIS excluded). We convolve the gridded mass distribution over the Earth's surface and obtain the potential coefficients in response to this distribution up to d/o 60.…”

Section: A2 the Gris Simulationmentioning

confidence: 99%

Improved GRACE regional mass balance estimates of the Greenland ice sheet cross-validated with the input–output method

Schrama

Wal

et al. 2016

The Cryosphere

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Abstract. In this study, we use satellite gravimetry data from the Gravity Recovery and Climate Experiment (GRACE) to estimate regional mass change of the Greenland ice sheet (GrIS) and neighboring glaciated regions using a least squares inversion approach. We also consider results from the input-output method (IOM). The IOM quantifies the difference between the mass input and output of the GrIS by studying the surface mass balance (SMB) and the ice discharge (D). We use the Regional Atmospheric Climate Model version 2.3 (RACMO2.3) to model the SMB and derive the ice discharge from 12 years of high-precision ice velocity and thickness surveys.We use a simulation model to quantify and correct for GRACE approximation errors in mass change between different subregions of the GrIS, and investigate the reliability of pre-1990s ice discharge estimates, which are based on the modeled runoff. We find that the difference between the IOM and our improved GRACE mass change estimates is reduced in terms of the long-term mass change when using a reference discharge derived from runoff estimates in several subareas. In most regions our GRACE and IOM solutions are consistent with other studies, but differences remain in the northwestern GrIS. We validate the GRACE mass balance in that region by considering several different GIA models and mass change estimates derived from data obtained by the Ice, Cloud and land Elevation Satellite (ICESat). We conclude that the approximated mass balance between GRACE and IOM is consistent in most GrIS regions. The difference in the northwest is likely due to underestimated uncertainties in the IOM solutions.

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“…Global mean sea level provides an excellent metric to monitor global change, and ample studies exist which attempt to close the global mean sea-level budget in terms of the different contributions (12-15). Unfortunately, the components of the sea-level budget still exhibit significant differences across studies depending on the chosen corrections, datasets, methods, and time periods (16,17).Understanding sea-level rise requires a well-established monitoring network, preferably covering long timespans. Besides important historic measurements from reprocessed tide gauge measurements (18), spaceborn techniques have become increasingly important over the last decades.…”

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confidence: 99%

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confidence: 99%

Revisiting the contemporary sea-level budget on global and regional scales

Rietbroek

Brunnabend

Kusche

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Dividing the sea-level budget into contributions from ice sheets and glaciers, the water cycle, steric expansion, and crustal movement is challenging, especially on regional scales. Here, Gravity Recovery And Climate Experiment (GRACE) gravity observations and sea-level anomalies from altimetry are used in a joint inversion, ensuring a consistent decomposition of the global and regional sea-level rise budget. Over the years 2002-2014, we find a global mean steric trend of 1.38 ± 0.16 mm/y, compared with a total trend of 2.74 ± 0.58 mm/y. This is significantly larger than steric trends derived from in situ temperature/salinity profiles and models which range from 0.66 ± 0.2 to 0.94 ± 0.1 mm/y. Mass contributions from ice sheets and glaciers (1.37 ± 0.09 mm/y, accelerating with 0.03 ± 0.02 mm/y 2 ) are offset by a negative hydrological component (−0.29 ± 0.26 mm/y). The combined mass rate (1.08 ± 0.3 mm/y) is smaller than previous GRACE estimates (up to 2 mm/y), but it is consistent with the sum of individual contributions (ice sheets, glaciers, and hydrology) found in literature. The altimetric sea-level budget is closed by coestimating a remaining component of 0.22 ± 0.26 mm/y. Well above average sea-level rise is found regionally near the Philippines (14.7 ± 4.39 mm/y) and Indonesia (8.3 ± 4.7 mm/y) which is dominated by steric components (11.2 ± 3.58 mm/y and 6.4 ± 3.18 mm/y, respectively). In contrast, in the central and Eastern part of the Pacific, negative steric trends (down to −2.8 ± 1.53 mm/y) are detected. Significant regional components are found, up to 5.3 ± 2.6 mm/y in the northwest Atlantic, which are likely due to ocean bottom pressure variations.lobal sea-level rise has been identified as one of the major threats associated with global climate change (1, 2). However, from the perspective of assessment-and decision-making, regional estimates of sea-level rise are even more important to formulate meaningful adaptation plans on a national or international level. Besides the magnitude of the total sea-level rise itself, identifying dominant drivers, and their corresponding uncertainties, may also prove beneficial for projection studies.Historical records from tide gauges indicate a sea-level rate of about 1.7 mm/y over the period 1900-2009, where it must be noted that tide gauges indicate an acceleration (0.009-0.017 mm/y 2 ) over the last century (3-5). Besides the steric expansion of sea water due to temperature changes, the ongoing melting and ablation of ice sheets in Greenland and Antarctica and other land glaciers cause the sea level to rise. Hydrological mass variability on land and reservoir construction have been found to cause a negative trend (6-9). Furthermore, meltwater, precipitation, or evaporation result in regional salinity changes, leaving steric signatures in sea level once the barotropic component has been compensated (10). For an observer at the coast, crustal movement, caused by glacial isostatic adjustment (GIA), tectonics, or local subsidence may also significantly affect the r...

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A mascon approach to assess ice sheet and glacier mass balances and their uncertainties from GRACE data

Cited by 120 publications

References 69 publications

Groundwater Storage Changes: Present Status from GRACE Observations

Groundwater Storage Changes: Present Status from GRACE Observations

Improved GRACE regional mass balance estimates of the Greenland ice sheet cross-validated with the input–output method

Revisiting the contemporary sea-level budget on global and regional scales

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