scholarly journals Determining dislocation Love numbers using satellite gravity mission observations

2006 ◽  
Vol 58 (5) ◽  
pp. 497-503 ◽  
Author(s):  
Wenke Sun ◽  
Shuhei Okubo ◽  
Takayuki Sugano
Keyword(s):  
Satellite Gravity ◽  
Love Numbers ◽  
Gravity Mission

scholarly journals ANALYSIS OF WATER MASS VARIATION IN WETLANDS REGIONS USING DATA FROM GRACE SATELLITE MISSION: THE PANTANAL CASE

2016 ◽  
Vol 34 (4) ◽  
Author(s):  
Cecilia Cornero ◽  
Ayelen Pereira ◽  
Ana Cristina Oliveira Cancoro de Matos ◽  
María Cristina Pacino
Keyword(s):  
Spatial Scales ◽  
Transport Processes ◽  
Satellite Mission ◽  
Satellite Gravity ◽  
Earth’S Gravity Field ◽  
Paraguay River ◽  
Using Data ◽  
Gravity Recovery ◽  
Gravity Field Models ◽  
Gravity Mission

ABSTRACT. The natural heritage of biodiversity of the Paraguay river basin is subject to potential impacts due to climate change. To monitor these environments at large spatial scales, the satellite gravity mission GRACE (Gravity Recovery and Climate Experiment) provides time-variable Earth’s gravity field models that reflect the variations due to mass transport processes, like continental...Keywords: water storage, satellite gravity mission, river gauge, rainfall. RESUMO. O patrimônio natural de biodiversidade da bacia do rio Paraguai está sujeito a potenciais impactos das mudanças climáticas. Para monitorar esse ambiente em escala espacial, a missão satelital GRACE (Gravity Recovery and Climate Experiment) fornece modelos do campo de gravidade da Terra variáveis no tempo devido ao processo de transporte de massa, como as variações de armazenamento de água...Palavras-chave: armazenamento de água, missão satelital, cotas do nível d’água, precipitação.

scholarly journals Quantifying the resolution level where the GRACE satellites can separate Greenland's glacial mass balance from surface mass balance

2015 ◽  
Vol 9 (1) ◽  
pp. 1315-1343
Author(s):  
J. A. Bonin ◽  
D. P. Chambers
Keyword(s):  
Mass Balance ◽  
Gravity Measurement ◽  
Surface Mass Balance ◽  
Satellite Gravity ◽  
Surface Mass ◽  
Grace Data ◽  
Resolution Level ◽  
Grace Satellites ◽  
Grace Satellite ◽  
Gravity Mission

Abstract. Mass change over Greenland can be caused by either changes in the glacial mass balance (GMB) or the precipitation-based surface mass balance (SMB). The GRACE satellite gravity mission cannot directly separate the two physical causes because it measures the sum of the entire mass column with limited spatial resolution. We demonstrate one theoretical way to indirectly separate SMB from GMB with GRACE, using a least squares inversion technique with knowledge of the location of the glacier. However, we find that the limited 60 × 60 spherical harmonic representation of current GRACE data does not provide sufficient resolution to adequately accomplish the task. We determine that at a maximum degree/order of 90 × 90 or above, a noise-free gravity measurement could theoretically separate the SMB from GMB signals. However, current GRACE satellite errors are too large at present to separate the signals. A noise reduction of a factor of 9 at a resolution of 90 × 90 would provide the accuracy needed for the interannual SMB and GMB to be accurately separated.

scholarly journals Quantifying the resolution level where the GRACE satellites can separate Greenland's glacial mass balance from surface mass balance

2015 ◽  
Vol 9 (5) ◽  
pp. 1761-1772 ◽  
Author(s):  
J. A. Bonin ◽  
D. P. Chambers
Keyword(s):  
Mass Balance ◽  
Gravity Measurement ◽  
Surface Mass Balance ◽  
Satellite Gravity ◽  
Surface Mass ◽  
Grace Data ◽  
Resolution Level ◽  
Grace Satellites ◽  
Grace Satellite ◽  
Gravity Mission

Abstract. Mass change over Greenland can be caused by either changes in the glacial dynamic mass balance (DMB) or the surface mass balance (SMB). The GRACE satellite gravity mission cannot directly separate the two physical causes because it measures the sum of the entire mass column with limited spatial resolution. We demonstrate one theoretical way to indirectly separate cumulative SMB from DMB with GRACE, using a least squares inversion technique with knowledge of the location of the glaciers. However, we find that the limited 60 × 60 spherical harmonic representation of current GRACE data does not provide sufficient resolution to adequately accomplish the task. We determine that at a maximum degree/order of 90 × 90 or above, a noise-free gravity measurement could theoretically separate the SMB from DMB signals. However, current GRACE satellite errors are too large at present to separate the signals. A noise reduction of a factor of 10 at a resolution of 90 × 90 would provide the accuracy needed for the interannual cumulative SMB and DMB to be accurately separated.

scholarly journals Attitude Determination for GRACE-FO: Reprocessing the Level-1A SC and IMU Data

2021 ◽  
Vol 14 (1) ◽  
pp. 126
Author(s):  
Fan Yang ◽  
Lei Liang ◽  
Changqing Wang ◽  
Zhicai Luo
Keyword(s):  
Kalman Filter ◽  
Attitude Determination ◽  
Angular Acceleration ◽  
Sensor Data ◽  
Combination Method ◽  
Measurement Unit ◽  
Filter Method ◽  
Satellite Gravity ◽  
Range Rate ◽  
Gravity Mission

The satellite gravity mission GRACE(-FO) has not yet reached its designed baseline accuracy. Previous studies demonstrated that the deficiency in the sensor system or the related signal processing might be responsible, which in turn motivates us to keep revising the sensor data processing, typically the spacecraft’s attitude. Many efforts in the past have been made to enhance the attitude modeling for GRACE, for instance, the latest release reprocesses the attitude by fusing the angular acceleration with the star camera/tracker (SC) measurements, which helps to reduce the error in Level-2 temporal gravity fields. Therefore, in addition to GRACE, revising GRACE-FO attitude determination might make sense as well. This study starts with the most original raw GRACE-FO Level-1A data including those from three SCs and one IMU (Inertial Measurement Unit) sensors, and manage to generate a new publicly available Level-1B attitude product called HUGG-01 covering from June 2018 to December 2020, using our independently-developed software. The detailed treatment of individual payload is present in this study, and an indirect Kalman filter method is introduced to fuse the multiple sensors to acquire a relatively stable and precise attitude estimation. Unlike the direct SC combination method with a predefined weight as recommended in previous work, we propose an involvement of each SC measurement in the Kalman filter to enable a dynamic weight adjustment. Intensive experiments are further carried out to assess the HUGG-01, which demonstrate that the error level of HUGG-01 is entirely within the design requirement, i.e., the resulting KBR pointing variations are well controlled within 1 mrad (pitch), 5 mrad (roll) and 1 mrad (yaw). Moreover, comparisons with the official JPL-V04 attitude product demonstrate an equivalent performance in the low-to-middle spectrum, with even a slightly lower noise level (in the high spectrum) than JPL-V04. Further analysis on KBR range-rate residuals and gravity recovery on Jan 2019 indicates that, i.e., RMS of the difference (HUGG-01 minus JPL-V04) for the range rate is less than 3.234×10−8 m/s, and the amplitude of geoid height difference is approximately 0.5 cm. Both differences are below the sensitivity of the state-of-the-art satellite gravity mission, demonstrating a good agreement between HUGG-01 and JPL-V04.

scholarly journals ANALYSIS OF WATER MASS VARIATIONS AT WETLANDS REGIONS FROM GRACE: THE PANTANAL CASE

2018 ◽  
Vol 35 (4) ◽  
pp. 307
Author(s):  
Cecilia Cornero ◽  
AYELEN PEREIRA ◽  
MARÍA CRISTINA PACINO
Keyword(s):  
Water Mass ◽  
Spatial Scales ◽  
Water Storage ◽  
Transport Processes ◽  
Satellite Gravity ◽  
The North ◽  
Paraguay River ◽  
Gravity Recovery ◽  
Gravity Mission

ABSTRACT. The natural heritage of biodiversity of the Paraguay river basin is subject to potential impacts due to climate change. To monitor these environments at large spatial scales, the satellite gravity mission GRACE (Gravity Recovery and Climate Experiment) provides time-variable Earth’s gravity field models that reflect the variations due to mass transport processes, like continental water storage changes. The purpose of this work is to analyze the spatial and temporal water storage changes for period 2003-2014 using the Equivalent Water Height (EWH) derived from the GRACE solutions in the Pantanal region, one of the most biologically rich environments of the planet. The comparison with EWH and river gauge data at different stations distributed over the Pantanal area was carried out. In order to validate the satellite results, the correlation analysis between the water mass changes and river gauge measurements was obtained, and also the phase differences were analyzed. High correlations were detected at the north, and lower ones towards the south of the Pantanal. The EWH were also contrasted with soil moisture and rainfall data models. The results showed a good agreement between the signals for the area under study.Keywords: water storage, satellite gravity mission, river gauge, rainfall. RESUMO. O patrimônio natural de biodiversidade da bacia do rio Paraguai está sujeito a potenciais impactos das mudanças climáticas. Para monitorar esse ambiente em escala espacial, a missão satelital GRACE (Gravity Recovery and Climate Experiment) fornece modelos do campo de gravidade da Terra variáveis no tempo devido ao processo de transporte de massa, como as variações de armazenamento de água continentais. O objetivo deste artigo é analisar a variabilidade espacial e temporal de armazenamento de água para o período 2003-2014 através da altura equivalente d’água (EWH) derivada das soluções deGRACE na região do Pantanal, um dos ambientes biologicamente mais ricos do planeta. Comparações dos dados de EWH e alturas d’água in-situ foram feitas para diferentes estações distribuídas na região do Pantanal. Com a finalidade de validar os resultados de satélite, foi feita a análise de correlação entre as mudanças de massa d’água e as medições das réguas linimétricas fixadas nas margens dos rios. As diferenças de fase também foram analisadas. Ao Norte do Pantanal foram detectadas altas correlações entre as duas alturas (EWH versus in-situ), e baixas em direção ao sul. O EWH também foi validado com modelos de umidade do solo e precipitação. Os resultados mostraram uma boa concordância entre os sinais para a área em estudo. Palavras-chave: armazenamento de água, missão satelital, cotas do nível d’água, precipitação.

scholarly journals Satellite gravity and the mass balance of the antarctic ice sheet

1998 ◽  
Vol 44 (147) ◽  
pp. 207-213 ◽  
Author(s):  
C. R. Bentley ◽  
J. M. Wahr
Keyword(s):  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Satellite Gravity ◽  
Antarctic Ice Sheet ◽  
Level Change ◽  
Gravity Measurements ◽  
The Antarctic ◽  
Gravity Mission

AbstractChanges in the Earth’s gravity field with time have important applications to a broad range of disciplines. Any process that involves a large enough horizontal redistribution of mass, either within the Earth or on or above its surface, is potentially detectable. In particular, when ice sheets grow or shrink, gravity changes as mass is redistributed in the solid earth and between the oceans and the ice sheets. The sources of global sea-level rise (about 2 mm a−1 over the last century) and in particular the contribution of the Antarctic ice sheet thereto are not well understood. Gravity measurements can help to diminish this uncertainty.The technology currently exists to measure gravity with high accuracy by a dual-satellite mission in which the distance between the satellites is precisely monitored. We estimate from recent studies that temporal changes in the gravity field as determined by a satellite gravity mission lasting 5 years at an orbital height of 400 km would be sensitive to changes in the overall mass of the Antarctic ice sheet to a precision corresponding to better than 0.01 mm a−1 of sea-level change. However, the effects of three other phenomena that could each produce a temporally varying gravity signal with characteristics comparable to that caused by a change in Antarctic ice—postglacial rebound, inter-annual variability in snowfall, and atmospheric pressure trends — also need to be evaluated. Postglacial rebound could be partly separated from ice-mass changes with the aid of global positioning system campaigns and numerical models of rebound that use improved determinations of mantle viscosity also provided by the gravity mission. Determination of inter-annual ice-mass changes will be aided by measurements of moisture-flux divergence around the perimeters of the ice sheets and direct observations of inter-annual changes by the gravity satellite itself. The removal of pressure effects over Antarctica will become more effective as the number of automatic weather stations in the interior of the continent increases.Even after corrections are made for these factors, the uncertainties they cause limit the accuracy in the détermination of the contribution of the Antarctic ice sheet to sea-level change to about 0.5 mm a−1. However, there is a strong complementarity between gravity measurements and the surface-height measurements that will be produced by NASA’s laser altimeter mission early next century. Together, they should be able to determine that contribution to an accuracy of about 0.1 mm a−1.

scholarly journals Satellite gravity and the mass balance of the antarctic ice sheet

1998 ◽  
Vol 44 (147) ◽  
pp. 207-213 ◽  
Author(s):  
C. R. Bentley ◽  
J. M. Wahr
Keyword(s):  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Satellite Gravity ◽  
Antarctic Ice Sheet ◽  
Level Change ◽  
Gravity Measurements ◽  
The Antarctic ◽  
Gravity Mission

AbstractChanges in the Earth’s gravity field with time have important applications to a broad range of disciplines. Any process that involves a large enough horizontal redistribution of mass, either within the Earth or on or above its surface, is potentially detectable. In particular, when ice sheets grow or shrink, gravity changes as mass is redistributed in the solid earth and between the oceans and the ice sheets. The sources of global sea-level rise (about 2 mm a−1over the last century) and in particular the contribution of the Antarctic ice sheet thereto are not well understood. Gravity measurements can help to diminish this uncertainty.The technology currently exists to measure gravity with high accuracy by a dual-satellite mission in which the distance between the satellites is precisely monitored. We estimate from recent studies that temporal changes in the gravity field as determined by a satellite gravity mission lasting 5 years at an orbital height of 400 km would be sensitive to changes in the overall mass of the Antarctic ice sheet to a precision corresponding to better than 0.01 mm a−1of sea-level change. However, the effects of three other phenomena that could each produce a temporally varying gravity signal with characteristics comparable to that caused by a change in Antarctic ice—postglacial rebound, inter-annual variability in snowfall, and atmospheric pressure trends — also need to be evaluated. Postglacial rebound could be partly separated from ice-mass changes with the aid of global positioning system campaigns and numerical models of rebound that use improved determinations of mantle viscosity also provided by the gravity mission. Determination of inter-annual ice-mass changes will be aided by measurements of moisture-flux divergence around the perimeters of the ice sheets and direct observations of inter-annual changes by the gravity satellite itself. The removal of pressure effects over Antarctica will become more effective as the number of automatic weather stations in the interior of the continent increases.Even after corrections are made for these factors, the uncertainties they cause limit the accuracy in the détermination of the contribution of the Antarctic ice sheet to sea-level change to about 0.5 mm a−1. However, there is a strong complementarity between gravity measurements and the surface-height measurements that will be produced by NASA’s laser altimeter mission early next century. Together, they should be able to determine that contribution to an accuracy of about 0.1 mm a−1.

Sign in / Sign up

Export Citation Format

Share Document