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	   3D high-resolution altimetry-derived marine gravity data  -  global data derived on the DTU21 mean sea surface 
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The grid files contain the first, second and third derivatives of the disturbing potential on the DTU21 mean sea surface (DTU21_MSS). They are expressed in the LNOF 
(Local North-Oriented Frame). The disturbing potential is obtained as a FVM numerical solution of the satellite-fixed altimetry-gravimetry boundary-value problem (AGBVP), 
for more details see (Čunderlík et al. 2025).


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DATA FORMAT:
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All grid files represent grids with the spacing 1 x 1 arc min that are stored in the ASCII grid file format of the Surfer, Golden Software, LLC (www.goldensoftware.com).
In this ‘.grd’ format, the Surfer header is followed by values at all grid points ordered ‘row-wise’ from west to east (longitude) and then from south to north (latitude).
All grd files are zipped using the 'gzip' program.

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GRID FILES:
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Tx_0m_STU25GRAV.grd.gz	  -    contains the first derivatives in the X direction, units: mGal (correspond to the north-south components of the deflection of vertical) 

Ty_0m_STU25GRAV.grd.gz	  -    contains the first derivatives in the Y direction, units: mGal (correspond to the east-west components of the deflection of vertical)  

Tz_0m_STU25GRAV.grd.gz	  -    contains the first derivatives in the Z direction, units: mGal (gravity disturbances) 


Txx_0m_STU25GRAV.grd.gz	  -    contains the second derivatives in the X direction, units: E  (Txx diagonal components of the gravity disturbing gradients)

Tyy_0m_STU25GRAV.grd.gz	  -    contains the second derivatives in the Y direction, units: E  (Tyy diagonal components of the gravity disturbing gradients)

Tzz_0m_STU25GRAV.grd.gz	  -    contains the second derivatives in the Z direction, units: E  (Tzz diagonal components of the gravity disturbing gradients)


Txy_0m_STU25GRAV.grd.gz	  -    contains the second derivatives in the X and Y directions, units: E  (Txy combined components of the gravity disturbing gradients)

Txz_0m_STU25GRAV.grd.gz	  -    contains the second derivatives in the X and Z directions, units: E  (Txz combined components of the gravity disturbing gradients)

Tyz_0m_STU25GRAV.grd.gz	  -    contains the second derivatives in the Y and Z directions, units: E  (Tyz combined components of the gravity disturbing gradients)


Txxx_0m_STU25GRAV.grd.gz  -    contains the third derivatives in the X direction, units: 10^-13 m/s^2

Tyyy_0m_STU25GRAV.grd.gz  -    contains the third derivatives in the Y direction, units: 10^-13 m/s^2

Tzzz_0m_STU25GRAV.grd.gz  -    contains the third derivatives in the Z direction, units: 10^-13 m/s^2



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REFERENCE:
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Please cite:

Čunderlík R, Macák M, Kollár M, Minarechová Z and Mikula K (2025) 3D high-resolution numerical modelling of altimetry-derived marine gravity data. Journal of Geodesy.