Grids of vertical gravity gradients and gravity anomalies at ground level (SPW)

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Model Characteristics
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Combined data grids at ground level (10 km altitude) from the space-wise approach (SPW), 
with error estimates. 
Gravity anomalies and radial gravity gradients on a 1/6 degree grid. 
Gradients and anomalies  are computed from GOCE data, a GRACE global model and 
airborne/ground gravity data over polar areas for the available time span 
(indicated in the product). 
 
Input 
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Externally calibrated GOCE GG (EGG_NOM_2_); GRF to IRF attitude quaternions (EGG_IAQ_1b); 
Precise Science Orbit (SST_PSO_2), which also includes the EFRF to IRF quaternions. 
In addition, a state-of-the-art a priori global gravity field model including GRACE data, 
terrestrial and airborne gravity data over polar areas and several ancillary products 
are used.

Algorithm 
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Contribution from GRACE model have been removed from GOCE and external gravity data. 
Data are divided into equal-area patches of 24x24 degrees with a 2deg overlap. 
Empirical covariance functions are calculated with EMPCOV and an analytic representation 
determined with COVFIT. 
Grid values and error estimates of the output functionals are computed through least 
squares collocation using GEOCOL with a resolution of 1/6 degree at an altitude of 10 km.

Additional information can be found at 
GRC updated model information