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

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