Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE

Wahr, John; Molenaar, Mery; Bryan, Frank O.

doi:10.1029/98jb02844

Cited by 1,826 publications

(1,892 citation statements)

References 33 publications

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“…Over the ocean, changes in the time-varying gravitational field reflect temporal variations of the OBP field. The conversion from gravitational field to OBP has been explained by Wahr et al (1998). Of particular interest to the polar research field is the orbit of the GRACE satellites (i.e., 898 of inclination), which allows for essentially full coverage over the Arctic Ocean, and better temporal resolution for high-latitude regions, where mass distribution changes in the ocean, along with mass changes because of glacier melt and hence sea level rise, are of major concern to climate change.…”

Section: Introductionmentioning

confidence: 99%

“…Ocean mass transport may be used to study overturning flow variations (Roussenov et al 2008), mass exchange between ocean basins (Hughes and Stepanov 2004;Stepanov and Hughes 2006;Chambers and Willis 2009), and freshwater changes in the ocean (Morison et al 2007(Morison et al , 2012. On a broader scale, changes in mass, and therefore changes in OBP, are directly related to water mass exchanges among the ocean, cryosphere, and hydrosphere (Wahr et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Arctic Ocean Circulation Patterns Revealed by GRACE

et al. 2014

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Measurements of ocean bottom pressure (OBP) anomalies from the satellite mission Gravity Recovery and Climate Experiment (GRACE), complemented by information from two ocean models, are used to investigate the variations and distribution of the Arctic Ocean mass from 2002 through 2011. The forcing and dynamics associated with the observed OBP changes are explored. Major findings are the identification of three primary temporal-spatial modes of OBP variability at monthly-to-interannual time scales with the following characteristics. Mode 1 (50% of the variance) is a wintertime basin-coherent Arctic mass change forced by southerly winds through Fram Strait, and to a lesser extent through Bering Strait. These winds generate northward geostrophic current anomalies that increase the mass in the Arctic Ocean. Mode 2 (20%) reveals a mass change along the Siberian shelves, driven by surface Ekman transport and associated with the Arctic Oscillation. Mode 3 (10%) reveals a mass dipole, with mass decreasing in the Chukchi, East Siberian, and Laptev Seas, and mass increasing in the Barents and Kara Seas. During the summer, the mass decrease on the East Siberian shelves is due to the basin-scale anticyclonic atmospheric circulation that removes mass from the shelves via Ekman transport. During the winter, the forcing mechanisms include a large-scale cyclonic atmospheric circulation in the eastern-central Arctic that produces mass divergence into the Canada Basin and the Barents Sea. In addition, strengthening of the Beaufort high tends to remove mass from the East Siberian and Chukchi Seas. Supporting previous modeling results, the month-to-month variability in OBP associated with each mode is predominantly of barotropic character.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Arctic Ocean Circulation Patterns Revealed by GRACE

et al. 2014

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“…Devido às mudanças no geóide serem consequências das variações de massas e efeitos de sobrecargas, pode-se expressá-las como: A formulação da EWT bem como o filtro Gaussiano foi apresentada por Wahr et al (1998), e pode ser resumida na seguinte expressão:…”

Section: Figura 1 -Região De Estudos E Estações Analisadas (Triângulounclassified

Análise de deformação por variação do geopotencial: estudo de caso para o terremoto maule (Mw 8,8) com base em dados mensais da missão Grace

Castro

Ferreira²,

Freitas

2012

Bol. Ciênc. Geod.

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RESUMOO Chile é um laboratório natural de estudos de Geodinâmica em vista da amplitude e variedade de eventos tectônicos. Um caso notável de deformação produzida é a decorrente do evento sísmico com magnitude 8,8w M = , denominado de terremoto do Maule. Este teve epicentro localizado a 60 km ao Sul de Constitución, região que já apresentava consideráveis velocidades obtidas por intermédio de medições GNSS. Vários estudos relacionados com o sinal geofísico gerado pelo terremoto foram realizados, principalmente explorados por intermédio deresultados GNSS e InSAR, somente um estudo com base em gravimetria. No entanto, tais estudos evidenciaram dificuldades relativas às séries temporais analisadas. Destaque-se que a maior parte das séries de posicionamento GNSS foram descontinuadas pelo evento e portanto só existem séries ou antes ou depois do evento. Neste estudo apresenta-se uma alternativa independente para a quantificação da deformação vertical da crosta com base nas variações do potencial anômalo fornecidas pelos coeficientes de

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“…On a monthly timescale, changes in gravity observed from space are mainly caused by changes in the mass of surface water (Wahr and Molenaar 1998). Due to the mission design and satellite orbit (polar orbit at an altitude of 500 km), Earth gravity changes are delivered as monthly spherical harmonic coefficients at the Earth surface with a spatial resolution around 300 km by the three data centers responsible for the GRACE mission (Geoforschungszentrum Postdam, GFZ; Center for Space Research at University of Texas, CSR; Jet Propulsion Laboratory, JPL; Wahr and Molenaar 1998;Jacob et al 2012;Sakumura et al 2014). The most recent gravity field from GRACE is the Level 2 Release 05 (RL05), which includes de-aliasing processing.…”

Section: Glacier Mass Change From Spaceborne Gravity Observationsmentioning

confidence: 99%

Observation-Based Estimates of Global Glacier Mass Change and Its Contribution to Sea-Level Change

Marzeion¹,

Champollion²,

Haeberli³

et al. 2017

Space Sciences Series of ISSI

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Glaciers have strongly contributed to sea-level rise during the past century and will continue to be an important part of the sea-level budget during the twenty-first century. Here, we review the progress in estimating global glacier mass change from in situ measurements of mass and length changes, remote sensing methods, and mass balance modeling driven by climate observations. For the period before the onset of satellite observations, different strategies to overcome the uncertainty associated with monitoring only a small sample of the world's glaciers have been developed. These methods now yield estimates generally reconcilable with each other within their respective uncertainty margins. Whereas this is also the case for the recent decades, the greatly increased number of estimates obtained from remote sensing reveals that gravimetry-based methods typically arrive at lower mass loss estimates than the other methods. We suggest that strategies for better interconnecting the different methods are needed to ensure progress and to increase the temporal and spatial detail of reliable glacier mass change estimates.

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Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE

Cited by 1,826 publications

References 33 publications

Arctic Ocean Circulation Patterns Revealed by GRACE

Arctic Ocean Circulation Patterns Revealed by GRACE

Análise de deformação por variação do geopotencial: estudo de caso para o terremoto maule (Mw 8,8) com base em dados mensais da missão Grace

Observation-Based Estimates of Global Glacier Mass Change and Its Contribution to Sea-Level Change

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