Seasonal variations in low degree zonal harmonics of the Earth's gravity field from satellite laser ranging observations

1999 ◽  
Vol 104 (B2) ◽  
pp. 2667-2681 ◽  
Author(s):  
Minkang Cheng ◽  
Byron D. Tapley
Keyword(s):  
Gravity Field ◽  
Seasonal Variations ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Earth’S Gravity Field ◽  
Zonal Harmonics ◽  
Low Degree

scholarly journals Accelerated ice mass depletion revealed by low-degree gravity field from satellite laser ranging: Greenland, 1991-2011

2013 ◽  
Vol 40 (17) ◽  
pp. 4662-4667 ◽  
Author(s):  
Koji Matsuo ◽  
Benjamin F. Chao ◽  
Toshimichi Otsubo ◽  
Kosuke Heki
Keyword(s):  
Gravity Field ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Low Degree ◽  
Mass Depletion

Impact of low-degree gravity field estimation in the SLR data processing of spherical satellites at AIUB

2021 ◽  
Author(s):  
Linda Geisser ◽  
Ulrich Meyer ◽  
Daniel Arnold ◽  
Adrian Jäggi ◽  
Daniela Thaller
Keyword(s):  
Gravity Field ◽  
Lower Altitude ◽  
Earth’S Gravity Field ◽  
Low Degree ◽  
Station Coordinates ◽  
Earth Rotation Parameters ◽  
Field Estimation ◽  
University Of Bern ◽  
The University ◽  
The Impact

<p>The Astronomical Institute of the University of Bern (AIUB) collaborates with the Federal Agency for Cartography and Geodesy (BKG) in Germany to develop new procedures to generate products for the International Laser Ranging Service (ILRS). In this framework the SLR processing of the standard ILRS weekly solutions of spherical geodetic satellites at AIUB, where the orbits are determined in 7-day arcs together with station coordinates and other geodetic parameters, is extended from LAGEOS-1/2 and the Etalon-1/2 satellites to also include the LARES satellite orbiting the Earth at much lower altitude. Since a lower orbit experiences a more variable enviroment, e.g. it is more sensitive to time-variable Earth's gravity field, the orbit parametrization has to be adapted and also the low degree spherical harmonic coefficients of Earth's gravity field have to be co-estimated. The impact of the gravity field estimation is studied by validating the quality of other geodetic parameters such as geocenter coordinates, Earth Rotation Parameters (ERPs) and station coordinates. The analysis of the influence of LARES on the SLR solution shows that a good datum definition is important.</p>

GRACE/GRACE-FO mascons and satellite laser ranging: Updates from GSFC

2020 ◽  
Author(s):  
Bryant Loomis ◽  
Michael Croteau ◽  
Terry Sabaka ◽  
Scott Luthcke ◽  
Kenny Rachlin
Keyword(s):  
Computational Cost ◽  
Technical Note ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Normal Equations ◽  
Low Degree ◽  
Damping Parameter ◽  
Variable Gravity ◽  
Trade Study ◽  
Comparable Quality

<p>We present a summary of our recent work on time-variable gravity estimates derived from GRACE/GRACE-FO and satellite laser ranging (SLR). We show the latest results of our monthly mascon solution, with special attention paid to the selection and impact of the damping parameter applied to the regularization matrices. Additionally, we present a new method of regularized mascon estimation from spherical harmonics. Provided that the full normal equations for these coefficients are available, this method allows for a mathematically equivalent mascon estimate to those determined from a single iteration solution from Level-1B observations, but at a fraction of the computational cost. For this we use the ITSG-Grace2018 solution and full normal equations to produce a new mascon solution of comparable quality to current mascon products, and we are in the process of using this rapid approach to perform a trade study of various regularization strategies. Lastly, we present low degree SLR solutions that form the basis of the C20 and C30 solutions provided in Technical Note 14, and present preliminary results of large SLR-derived mascons from 1993 – Present.</p>

scholarly journals Accelerated ice-sheet mass loss in Antarctica from 18-year satellite laser ranging measurements

2016 ◽  
Vol 59 (1) ◽  
Author(s):  
Shuanggen Jin ◽  
Mosta Abd-Elbaky ◽  
Guping Feng
Keyword(s):  
Ice Sheet ◽  
Accurate Estimate ◽  
East Antarctica ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
West Antarctica ◽  
Low Degree ◽  
Ice Sheet Mass Balance ◽  
Good Agreement

<p>Accurate estimate of the ice-sheet mass balance in Antarctic is very difficult due to complex ice sheet condition and sparse in situ measurements. In this paper, the low-degree gravity field coefficients of up to degree and order 5 derived from Satellite Laser Ranging (SLR) measurements are used to determine the ice mass variations in Antarctica for the period 1993–2011. Results show that the ice mass is losing with -36±13 Gt/y in Antarctica, -42±11 Gt/y in the West Antarctica and 6±10 Gt/y in the East Antarctica from 1993 to 2011. The ice mass variations from the SLR 5×5 have a good agreement with the GRACE 5×5, GRACE 5×5 (1&amp;2) and GRACE (60×60) for the entire continent since 2003, but degree 5 from SLR is not sufficient to quantify ice losses in West and East Antarctica, respectively. The rate of ice loss in Antarctica is -28±17 Gt/y for 1993-2002 and -55±17 Gt/y for 2003-2011, indicating significant accelerated ice mass losses since 2003. Furthermore, the results from SLR are comparable with GRACE measurements.</p>

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