Time Variable Gravity: Contributions of GOCE Satellite Data to Monthly and Bi-monthly GRACE Gravity Estimates

A feasibility study by Pail et al. (Can GOCE help to improve temporal gravity field estimates? In: Ouwehand L (ed) Proceedings of the 4th International GOCE User Workshop, ESA Publication SP-696, 2011b) shows that GOCE (‘Gravity field and steady-state Ocean Circulation Explorer’) satellite gravity gradiometer (SGG) data in combination with GPS derived orbit data (satellite-to-satellite tracking: SST-hl) can be used to stabilize and reduce the striping pattern of a bi-monthly GRACE (‘Gravity Recovery and Climate Experiment’) gravity field estimate. In this study several monthly (and bi-monthly) combinations of GRACE with GOCE SGG and GOCE SST-hl data on the basis of normal equations are investigated. Our aim is to assess the role of the gradients (solely) in the combination and whether already one month of GOCE observations provides sufficient data for having an impact in the combination. The estimation of clean and stable monthly GOCE SGG normal equations at high resolution ( >  d/o 150) is found to be difficult, and the SGG component, solely, does not show significant added value to monthly and bi-monthly GRACE gravity fields. Comparisons of GRACE-only and combined monthly and bi-monthly solutions show that the striping pattern can only be reduced when using both GOCE observation types (SGG, SST-hl), and mainly between d/o 45 and 60.

Grace Hawthorne als Theodora, Rollenbild, London

Signatur des Originals: S 36/F08785

Grace Pedley, Rollenbild, Hüftbild, in: Joan of Arc

Signatur des Originals: S 36/F09498

(Table 1) GRACE-derived mass balance of the Greenland ice sheet 2002-2010

We re-evaluate the Greenland mass balance for the recent period using low-pass Independent Component Analysis (ICA) post-processing of the Level-2 GRACE data (2002-2010) from different official providers (UTCSR, JPL, GFZ) and confirm the present important ice mass loss in the range of -70 and -90 Gt/y of this ice sheet, due to negative contributions of the glaciers on the east coast. We highlight the high interannual variability of mass variations of the Greenland Ice Sheet (GrIS), especially the recent deceleration of ice loss in 2009-2010, once seasonal cycles are robustly removed by Seasonal Trend Loess (STL) decomposition. Interannual variability leads to varying trend estimates depending on the considered time span. Correction of post-glacial rebound effects on ice mass trend estimates represents no more than 8 Gt/y over the whole ice sheet. We also investigate possible climatic causes that can explain these ice mass interannual variations, as strong correlations between GRACE-based mass balance and atmosphere/ocean parallels are established: (1) changes in snow accumulation, and (2) the influence of inputs of warm ocean water that periodically accelerate the calving of glaciers in coastal regions and, feed-back effects of coastal water cooling by fresh currents from glaciers melting. These results suggest that the Greenland mass balance is driven by coastal sea surface temperature at time scales shorter than accumulation.

Del combinado al satélite : Trayectorias, redes y estrategias empresariales del complejo electrónico cordobés

Fil: Berti, Natalia Teresa. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Del combinado al satélite : Trayectorias, redes y estrategias empresariales del complejo electrónico cordobés

Fil: Berti, Natalia Teresa. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Del combinado al satélite : Trayectorias, redes y estrategias empresariales del complejo electrónico cordobés

Fil: Berti, Natalia Teresa. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Global and Regional Sea level budget components from GRACE and radar altimetry (2002-2014)

This dataset contains the result of a joint least squares inversion of GRACE and altimetry data. The results are evaluated in terms of sea level change for the global ocean as well as dedicated areas. In addition, some auxiliary data is provided to enable reproducibility of the results in Rietbroek et al. 2016, and a google Earth kmz file is provided which visualizes the trends derived from the inversion results.