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Onshore and offshore free-air gravity of the New Zealand Region

A gravity map of the New Zealand region has been created from onshore observations and satellite altimetry.

Onshore gravity is free-air Gravity Anomaly from the GNS database ( http://dx.doi.org/10.21420/DRDW-VC7 2). Data were processed as described in the Terrestrial gravity section of McCubbine et al. (2017). Offshore gravity (and onshore outside of mainland NZ) is Free Air Gravity Anomaly

Sandwell and Smith 1 minute land and ocean gravity grid v29 (2020).

Simple

Date (Creation)
2020-07-27
Cited responsible party
Organisation name Individual name Electronic mail address Role

GNS Science

Point of contact
Purpose

This resource is a map layer used in conjunction with E Tūhura - Explore Zealandia (TEZ). TEZ is an interactive web-based GIS tool that allows users to discover and access a wide range of geoscience data.

Credit

GNS Science

Credit

Sandwell, D. T., Harper, H., Tozer, B. & Smith, W. H. F. (2019). Gravity field recovery from geodetic altimeter missions. Advances in Space Research. https://doi.org/10.1016/j.asr.2019.09.0 11

Credit

McCubbine, J. C., Stagpoole, V., Caratori Tontini, F., Amos, M., Smith, E. & Winefield, R., 2017. Gravity anomaly grids for the New Zealand region, New Zealand Journal of Geology and Geophysics. http://dx.doi.org/10.1080/00288306.2017.134669 2

Status
On going
Point of contact
Organisation name Individual name Electronic mail address Role

GNS Science

resources@gns.cri.nz

Point of contact
Maintenance and update frequency
As needed
Metadata author
Organisation name Individual name Electronic mail address Role

GNS Science

Point of contact
Keywords
  • Gravity surveys

Keywords
  • Position

Keywords
  • New Zealand

Keywords
  • gravimetry

Keywords
  • satellite derived gravity

Keywords
  • Free-air anomaly

Classification
Unclassified
Use constraints
Other restrictions
Other constraints

For publications, please include the following references:

Sandwell, D. T., Harper, H., Tozer, B. & Smith, W. H. F. (2019). Gravity field recovery from geodetic altimeter missions. Advances in Space Research. https://doi.org/10.1016/j.asr.2019.09.0 11

McCubbine, J. C., Stagpoole, V., Caratori Tontini, F., Amos, M., Smith, E. & Winefield, R., 2017. Gravity anomaly grids for the New Zealand region, New Zealand Journal of Geology and Geophysics. http://dx.doi.org/10.1080/00288306.2017.134669 2

Spatial representation type
Grid
Denominator
200000
Distance
1   1 minute
Language
English
Geographic identifier
EPSG:4326
N
S
E
W
thumbnail


Begin date
2020-07-27
End date
2020-07-27
Distribution format
Name Version

NetCDF

CF-1.5

OnLine resource
Protocol Linkage Name

WWW:LINK-1.0-http--link

WWW:LINK-1.0-http--link

https://data.gns.cri.nz/tez/
Hierarchy level
Model
Other

Gravity grid

Statement

Onshore gravity is free-air Gravity Anomaly from the GNS database ( http://dx.doi.org/10.21420/DRDW-VC7 2). Data were processed as described in the Terrestrial gravity section of McCubbine et al. (2017). Any observation with a recorded height more than ±10 m different from the height determined from an 8 m DEM have not been used in the gridding. Onshore gravity is in terms of the IGSN71 reference gravity.

Offshore gravity (and onshore outside of mainland NZ) is Free Air Gravity Anomaly

Sandwell and Smith 1 minute land and ocean gravity grid v29 (2020). Latitudes +/- 80 deg.

Format: GMT netCDF (32-bit float) pixel registration.

Downloaded from ftp://topex.ucsd.edu/pub/global_grav_1min/grav_29.1.nc on July 23, 2020 by Brook Tozer .

Ocean data is derived from satellite altimetry.

Land data from EGM2008 global gravity model.


Onshore point data and offshore satellite derived data are combined by first removing all offshore data within 10 km of the coast and then interpolating between the coastline and 10 km offshore. Note gravity values in this strip (0-10 km from the coast) are likely to contain large errors. This is done to ensure a smooth transition in the anomalies across the coast as the near shore satellite data has large errors due to tidal and other effects.


Onshore and offshore components originally created at 1 arc minute, combined dataset gridded at 15 arc seconds.


Copyright information:

Version release notes: ftp://topex.ucsd.edu/pub/global_grav_1min/README_V29.txt

Method used: ftp://topex.ucsd.edu/pub/global_grav_1min/grav_29.1.nc


References

McCubbine, J. C., Stagpoole, V., Caratori Tontini, F., Amos, M., Smith, E. & Winefield, R., 2017. Gravity anomaly grids for the New Zealand region, New Zealand Journal of Geology and Geophysics. http://dx.doi.org/10.1080/00288306.2017.134669 2


Sandwell, D. T., Harper, H., Tozer, B. & Smith, W. H. F. (2019). Gravity field recovery from geodetic altimeter missions. Advances in Space Research. https://doi.org/10.1016/j.asr.2019.09.0 11

Metadata

File identifier
2d0934f9-9fd9-4a76-a4d2-9eeae8ebc32e XML
Metadata language
English
Character set
UTF8
Hierarchy level
Model
Hierarchy level name

Model

Date stamp
2020-07-27T15:38:30
Metadata standard name

ISO 19115:2003/19139

Metadata standard version

1.0

Metadata author
Organisation name Individual name Electronic mail address Role

GNS Science

datamanagement@gns.cri.nz

Point of contact

GNS Science

Brook Tozer and Vaughan Stagpoole

Point of contact
 
 

Overviews

overview

Spatial extent

N
S
E
W
thumbnail


Keywords

Free-air anomaly New Zealand Position gravimetry satellite derived gravity

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