Date (Creation)

2022-04-29

Date (Revision)

2022-04-29

Date (Publication)

2022-04-29

Date (released)

2022-04-29

Edition

1.0

Unique resource identifier

https://doi.org/10.5285/930b782e-dfd2-4b7a-9a88-7cd03c024080

Codespace

doi

Unique resource identifier

GB/NERC/BAS/PDC/01642

Codespace

https://data.bas.ac.uk/

Unique resource identifier

NE/R000654/1

Codespace

award

Other citation details

Please cite this item as: Heorton, H. (2022). UCL CPOM CryoSat2 derived Dynamic Ocean Topography 2011-2021 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/930b782e-dfd2-4b7a-9a88-7cd03c024080

Credit

No credit.

Status

Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
University College London	Heorton, Harold		Author
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Point of contact

Maintenance and update frequency

As needed

Maintenance note

Completed

Global Change Master Directory (GCMD) Science Keywords

• EARTH SCIENCE > Oceans > Sea Surface Topography

Theme

• Antarctic

• Ocean

• surface currents

Place

• Arctic

• Antarctica

GEMET - INSPIRE themes, version 1.0

• Oceanographic geographical features

Access constraints

Other restrictions

Other constraints

no limitations to public access

Access constraints

Other restrictions

Other constraints

no limitations

Use constraints

License

Other constraints

Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

Data released under Open Government Licence V3.0:

Use constraints

Other restrictions

Other constraints

None.

Unique resource identifier

url

Codespace

url

Association Type

Cross reference

Unique resource identifier

url

Codespace

url

Association Type

Larger work citation

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Spatial representation type

Text, table

Language

English

Character set

UTF8

Topic category

• Environment
• Oceans

Begin date

2011-01-01

End date

2020-04-30

Supplemental Information

It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk.

Title

European Petroleum Survey Group (EPSG) Geodetic Parameter Registry

Date (Publication)

2008-11-12

Cited responsible party

Organisation name	Individual name	Electronic mail address	Role
European Petroleum Survey Group		EPSGadministrator@iogp.org	Publisher

Unique resource identifier

urn:ogc:def:crs:EPSG::3031

Version

6.18.3

Hierarchy level

Dataset

Statement

Methodology:

We take UCL CPOM processed CryoSat2 altimetry measurements of sea surface elevation, from the open ocean or from cracks within the sea ice cover. These records are from 4 satellite modes, LRM, SAR Ocean, SAR lead and SARIN lead. We take the UCL13 Mean Sea Surface product to calculate Sea Level Anomaly (SLA) for all 4 modes. We then calculate a monthly mean offset between, in order, LRM to SAR ocean, SAR ocean to SAR lead, SAR lead to SARIN lead, from coincident measurements on a 100 km resolution grid to remove mode bias' compared to the LRM mode SLA. We then use the GOCO03s geoid to calculate the dynamic ocean topography, then removing the bias from the SLA calculation. The DOT is smoothed over a 100 km Guassian kernel, with gradients to this field giving the surface monthly geostrophic currents. Data quality filtering is under taken at every step of the processing.

Data collection:

CryoSat2 LRM, SAR and SARIN mode radar altimeter.

Data quality:

This is a level 2 gridded data product that has gone under extensive data quality filtering.

Individual elevation measurements are filtered to be for the specific surface type (see above).

When gridding the elevation measurements we first trim off the lowest and highest 20th percentiles before calculating the mean.

The gridded data product has many missing values for land points where the data is inapplicable.

When smoothing the DOT surface we ignore all grid cells in the 1st and 99th precentile and leave these masked similar to a land point. These outlying cells can occur due to satellite altimeter encountering small islands not found in the land mask.

As we apply bias correction to the different satellite modes we have to be careful that the satellite was operating in its standard configuration. For example some months have data points in LRM mode where we usually expect SAR mode. These tracks have to be removed. This was performed manually.

Metadata

File identifier

930b782e-dfd2-4b7a-9a88-7cd03c024080 XML

Metadata language

English

Character set

UTF8

Hierarchy level

Dataset

Hierarchy level name

dataset

Date stamp

2022-04-29

Metadata standard name

ISO 19115 Geographic Information - Metadata

Metadata standard version

ISO 19115:2003(E)

Metadata author

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		polardatacentre@bas.ac.uk	Point of contact