Time-Variable Gravity from Satellites

Wahr, John

doi:10.1016/b978-0-444-53802-4.00065-8

Cited by 12 publications

(8 citation statements)

References 145 publications

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“…For more information on the GRACE mission, the gravity recovery process and the derivation of water storage anomalies from the spherical harmonic coefficients, we refer the reader to the reviews from Wouters et al (2014) or Wahr (2015) and the references therein. The gridded product used in this study is the GRACE Tellus dataset (available at http://grace.jpl.nasa.gov).…”

Section: Grace Datamentioning

confidence: 99%

“…It is thus important to monitor changes in land water storage, as well as the underlying processes leading to their variations in space and time. The Gravity Recovery and Climate Experiment (GRACE), launched in 2002, constitutes an essential tool for such analyses, as was demonstrated in a wealth of studies (Tapley et al 2004a;Wahr et al 2004;Rodell et al 2004;Andersen et al 2005;Velicogna and Wahr 2006;Güntner et al 2007a;Ramillien et al 2008;Zaitchik et al 2008;Rodell et al 2009;Chen et al 2010a;Houborg et al 2012;Sasgen et al 2012;Gardner et al 2013;Wouters et al 2014;Reager et al 2014;Famiglietti 2014;Chen et al 2015;Wahr 2015). After more than a decade of observations, the GRACE mission has resulted in an unprecedented view on global water storage variability, with a great diversity in terms of temporal scales, ranging from long-term trends to short-lived deviations from the seasonal cycle.…”

Section: Introductionmentioning

confidence: 99%

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Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes

Humphrey

Gudmundsson

Seneviratne

2016

Remote Sensing and Water Resources

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Throughout the past decade, the Gravity Recovery and Climate Experiment (GRACE) has given an unprecedented view on global variations in terrestrial water storage. While an increasing number of case studies have provided a rich overview on regional analyses, a global assessment on the dominant features of GRACE variability is still lacking. To address this, we survey key features of temporal variability in the GRACE record by decomposing gridded time series of monthly equivalent water height into linear trends, inter-annual, seasonal, and subseasonal (intra-annual) components. We provide an overview of the relative importance and spatial distribution of these components globally. A correlation analysis with precipitation and temperature reveals that both the inter-annual and subseasonal anomalies are tightly related to fluctuations in the atmospheric forcing. As a novelty, we show that for large regions of the world high-frequency anomalies in the monthly GRACE signal, which have been partly interpreted as noise, can be statistically reconstructed from daily precipitation once an adequate averaging filter is applied. This filter integrates the temporally decaying contribution of precipitation to the storage changes in any given month, including earlier precipitation. Finally, we also survey extreme dry anomalies in the GRACE record and relate them to documented drought events. This global assessment sets regional studies in a broader context and reveals phenomena that had not been documented so far.

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Section: Grace Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes

Humphrey

Gudmundsson

Seneviratne

2016

Remote Sensing and Water Resources

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“…The GRACE US-German twin satellite mission provides estimates of month-to-month changes in the gravitational field of the Earth mainly based on precise K-band microwave measurements of the distance between two low-flying satellites (Wahr, 2009) (Petit and Luzum, 2010) and oceans (Savcenko and Bosch, 2012), as well as due to non-tidal variability in the atmosphere and oceans ) from the observations, the resulting gravity changes mainly represent mass transport phenomena in the Earth system, which are -apart from long-term trends -almost exclusively related to the global water cycle.…”

Section: Tws Estimates From Gracementioning

confidence: 99%

Validation of terrestrial water storage variations as simulated by different global numerical models with GRACE satellite observations

Zhang

Dobslaw

Stacke

et al. 2017

Hydrol. Earth Syst. Sci.

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Abstract. Estimates of terrestrial water storage (TWS) variations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are used to assess the accuracy of four global numerical model realizations that simulate the continental branch of the global water cycle. Based on four different validation metrics, we demonstrate that for the 31 largest discharge basins worldwide all model runs agree with the observations to a very limited degree only, together with large spreads among the models themselves. Since we apply a common atmospheric forcing data set to all hydrological models considered, we conclude that those discrepancies are not entirely related to uncertainties in meteorologic input, but instead to the model structure and parametrization, and in particular to the representation of individual storage components with different spatial characteristics in each of the models. TWS as monitored by the GRACE mission is therefore a valuable validation data set for global numerical simulations of the terrestrial water storage since it is sensitive to very different model physics in individual basins, which offers helpful insight to modellers for the future improvement of large-scale numerical models of the global terrestrial water cycle.

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“…The Earth's constantly changing mass distribution varies its gravity field over time (Wahr and Schubert, 2007). Large-scale mass variations are generated by huge mass redistributions over large areas, such as conventions in the core and in the mantle, tectonic processes, earthquakes and volcano activity, tidal deformations of crust and oceans, circulations in the atmosphere and in the oceans, the hydrologic cycle, cryospheric processes, de-glaciation or the global sea level rise.…”

Section: Introductionmentioning

confidence: 99%

Comparison of seasonal hydrologic variations in the La Plata basin from GRACE monthly solutions with in situ gauge water level data

Kiss¹

2016

Acta Geodynamica Et Geomaterialia

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Seasonal hydrologic variations have been determined in the La Plata basin from GRACE monthly solutions for a time span of less than 6 years. The results have been compared to tide gauge water level data along several rivers of the La Plata basin. Annual and semi-annual curves have been fitted both to the GRACE water storage variation series and to the tide gauge water level series, correlations between the original series and the curves have been determined, relationship of the amplitudes and phases have been investigated. The aim of the comparison is to detect time delay between the seasonal cycle of precipitation (related to GRACE) and runoff (observed by tide gauges). The time delay may deliver information on water storage, such as groundwater aquifers, soil moisture or canopy interception. As for the results, by the comparison of the annual phases, 11-13 days of time delay between GRACE data and tide gauge data has been detected.

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Time-Variable Gravity from Satellites

Cited by 12 publications

References 145 publications

Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes

Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes

Validation of terrestrial water storage variations as simulated by different global numerical models with GRACE satellite observations

Comparison of seasonal hydrologic variations in the La Plata basin from GRACE monthly solutions with in situ gauge water level data

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