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

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>

Contribution of satellite laser ranging to combined gravity field models

2012 ◽  
Vol 49 (3) ◽  
pp. 556-565 ◽  
Author(s):  
A. Maier ◽  
S. Krauss ◽  
W. Hausleitner ◽  
O. Baur
Keyword(s):  
Gravity Field ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Gravity Field Models

scholarly journals A hybrid approach for recovering high-resolution temporal gravity fields from satellite laser ranging

2020 ◽  
Vol 95 (1) ◽  
Author(s):  
Anno Löcher ◽  
Jürgen Kusche
Keyword(s):  
Gravity Field ◽  
Spatial Resolution ◽  
Hybrid Approach ◽  
Greenland Ice Sheet ◽  
Time Frame ◽  
Empirical Orthogonal Functions ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Orthogonal Functions ◽  
Gravity Fields

AbstractA new approach to recover time-variable gravity fields from satellite laser ranging (SLR) is presented. It takes up the concept of lumped coefficients by representing the temporal changes of the Earth’s gravity field by spatial patterns via combinations of spherical harmonics. These patterns are derived from the GRACE mission by decomposing the series of monthly gravity field solutions into empirical orthogonal functions (EOFs). The basic idea of the approach is then to use the leading EOFs as base functions in the gravity field modelling and to adjust the respective scaling factors straightforward within the dynamic orbit computation; only for the lowest degrees, the spherical harmonic coefficients are estimated separately. As a result, the estimated gravity fields have formally the same spatial resolution as GRACE. It is shown that, within the GRACE time frame, both the secular and the seasonal signals in the GRACE time series are reproduced with high accuracy. In the period prior to GRACE, the SLR solutions are in good agreement with other techniques and models and confirm, for instance, that the Greenland ice sheet was stable until the late 1990s. Further validation is done with the first monthly fields from GRACE Follow-On, showing a similar agreement as with GRACE itself. Significant differences to the reference data only emerge occasionally when zooming into smaller river basins with strong interannual mass variations. In such cases, the approach reaches its limits which are set by the low spectral sensitivity of the SLR satellites and the strong constraints exerted by the EOFs. The benefit achieved by the enhanced spatial resolution has to be seen, therefore, primarily in the proper capturing of the mass signal in medium or large areas rather than in the opportunity to focus on isolated spatial details.

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