Earth gravity grid at 10 arc-minute resolution

Earth gravity grid at 10 arc-minute resolution

The grid is grid-node registered and stored in netCDF with CF-compliant metadata. The gravity values are derived from the EIGEN-6C4 spherical harmonic model. Here “gravity” refers to the combined gravitational and centrifugal accelerations.

The data are calculated uniformly at 10 km above the WGS84 ellipsoid.

Original source: EIGEN-6C4 model

Pre-processing: Source code for preparation of the original dataset for redistribution in Ensaio

import pygmt
import xarray as xr

import ensaio

Download and cache the data and return the path to it on disk.

Out:

/home/runner/work/_temp/cache/ensaio/v1/earth-gravity-10arcmin.nc

Load the netCDF grid with xarray.

<xarray.DataArray 'gravity' (latitude: 1081, longitude: 2161)>
array([[980106.5 , 980106.5 , 980106.5 , ..., 980106.5 , 980106.5 ,
        980106.5 ],
       [980108.25, 980108.25, 980108.25, ..., 980108.25, 980108.25,
        980108.25],
       [980108.8 , 980108.8 , 980108.8 , ..., 980108.75, 980108.75,
        980108.8 ],
       ...,
       [980153.8 , 980153.75, 980153.6 , ..., 980153.94, 980153.8 ,
        980153.8 ],
       [980160.44, 980160.44, 980160.44, ..., 980160.44, 980160.44,
        980160.44],
       [980157.5 , 980157.5 , 980157.5 , ..., 980157.5 , 980157.5 ,
        980157.5 ]], dtype=float32)
Coordinates:
  * longitude  (longitude) float64 -180.0 -179.8 -179.7 ... 179.7 179.8 180.0
  * latitude   (latitude) float64 -90.0 -89.83 -89.67 -89.5 ... 89.67 89.83 90.0
    height     (latitude, longitude) float32 1e+04 1e+04 1e+04 ... 1e+04 1e+04
Attributes:
    Conventions:     CF-1.8
    title:           Gravity acceleration (EIGEN-6C4) at a constant geometric...
    crs:             WGS84
    source:          Generated from the EIGEN-6C4 model by the ICGEM Calculat...
    license:         Creative Commons Attribution 4.0 International Licence
    references:      https://doi.org/10.5880/icgem.2015.1
    long_name:       gravity acceleration
    description:     magnitude of the gravity acceleration vector (gravitatio...
    units:           mGal
    actual_range:    [974748.6 980201.9]
    icgem_metadata:  generating_institute: gfz-potsdam\ngenerating_date: 2021...


Make a PyGMT pseudo-color map of the grid in a Mollweide projection.

fig = pygmt.Figure()
fig.basemap(
    region="g",
    projection="W15c",
    frame=True,
)
fig.grdimage(data, cmap="viridis", shading="+nt0.5")
fig.colorbar(frame='af+l"gravity [mGal]"')
fig.coast(shorelines=True, resolution="c", area_thresh=1e4)
fig.show()
earth gravity

Out:

<IPython.core.display.Image object>

Total running time of the script: ( 0 minutes 19.279 seconds)

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