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The recovery of Earth’s global gravity field from GOCE observations

The recovery of Earth’s global gravity field from GOCE observations

Leaders:  Prof. Dr.-Ing. Jürgen Müller
Email:  wuhu@ife.uni-hannover.de
Team:  Dr.-Ing. Hu Wu
Year:  2011
Sponsors:  Stipendium
Lifespan:  2011-2016
Is Finished:  yes

The ESA’s GOCE (Gravity field and steady-state Ocean Circulation Explorer) mission was the first to jointly apply SGG (satellite gravity gradiometry) and SST-hl (satellite-to-satellite high-low tracking) techniques to map the Earth’s gravity field. It delivered hundreds of millions of observations in four years’ lifetime, from 2009 to 2013. My Ph.D work is to recover a global gravity field model that is described by 62,997 spherical harmonic coefficients (up to degree/order 250) from the huge amount of GOCE observations. To achieve the goal, I developed a fortran-based software platform. It mainly includes modules for:

  • data screening: outlier detection, non-gravity reduction, dealing with data gaps, down-sampling, numerical differentiator, etc.;

  • numerical modelling: functional modelling for the SGG (gravity gradients) and SST-hl (precise kinematic orbit) data, stochastic modelling for colour noise, least-squares adjustment, filtering and regularization;

  • validation: analysis of post-fit residuals, analysis of the recovered models in the spectral and spatial domain.

 

In addition, parallel computing libraries openmp, mpi and the optimization library mkl have been tested and applied for the large-scale matrix computation. Our recovered model is named as IfE_GOCE05s, which shows comparable accuracy and resolution with the GOCE official solutions. 

  1. Hu Wu (2016). Gravity field recovery from GOCE observations. Wissenschaftliche Arbeiten der Fachrichtung Geodäsie und Geoinformatik der Leibniz Universität Hannover, Nr. 324, Hannover, 2016 (identisch mit: Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften, Reihe C, Nr. 777, München, 2016)

  2. Hu Wu, Jürgen Müller, Phillip Brieden (2017). The GOCE-only global gravity field model IfE_GOCE05s. GFZ Data Services. http://doi.org/10.5880/icgem.2017.006

Data: The IfE_GOCE05s model can be downloaded from the ICGEM website.