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Gridded SAM and ENSO coefficients derived from satellite altimeter data over the Antarctic Ice Sheet, 2002-2020

The data result from an analysis of gridded satellite altimetry time series of ice surface elevation for the Antarctic Ice Sheet. Multiple linear regression is performed, including parameters associated with the cumulative sum of each of the Southern Annular Mode (SAM) and El Nino/Southern Oscillation (ENSO). The gridded data include the original data and the derived parameters and statistical values. Four grids are provided. Two grids are from separate regressions performed on data after applying one of two different spatial smoothing filters (10 km and 200 km Gaussian functions). Two further grids are from regressions after subtracting one of two firn densification models from the 10 km-smoothed altimetry data.

Simple

Identification info

Date (Publication)
2024-04-24T00:00:00

Resource provider

Institute for Marine and Antarctic Studies (IMAS)
Private Bag 129
Hobart
Tasmania
7001
Australia

Author

School of Geography, Planning, and Spatial Sciences, University of Tasmania - King, Matt
ORCiD ID >

Oceans and Cryosphere, University of Tasmania - Christoffersen, Poul
ORCiD ID >

Credit
Australian Centre for Excellence in Antarctic Science
Credit
This work was supported by the ARC Australian Centre for Excellence in Antarctic Science (Project ID SR200100008)
Status
Completed

Author

School of Geography, Planning, and Spatial Sciences, University of Tasmania - King, Matt
ORCID ID >

Topic category
  • Climatology, meteorology, atmosphere

Extent

N
S
E
W


Temporal extent

Time period
2002-01-01 2020-12-31
Maintenance and update frequency
Not planned
Keywords (Theme)
  • ice
  • ice sheet
  • satellite altimetry
  • GRACE gravimetry
  • Southern Annular Mode (SAM)
  • El Nino Southern Oscillation (ENSO)
Global Change Master Directory Earth Science Keywords, Version 8.5
  • EARTH SCIENCE | CRYOSPHERE | GLACIERS/ICE SHEETS | GLACIER MASS BALANCE/ICE SHEET MASS BALANCE
  • EARTH SCIENCE | CLIMATE INDICATORS
  • EARTH SCIENCE | CLIMATE INDICATORS | CRYOSPHERIC INDICATORS | GLACIAL MEASUREMENTS | GLACIER ELEVATION/ICE SHEET ELEVATION
AODN Discovery Parameter Vocabulary
  • ice elevation
AODN Instrument Vocabulary
  • altimeter
AODN Geographic Extents Vocabulary
  • Continents | Continents | Antarctica
Australian and New Zealand Standard Research Classification (ANZSRC): Fields of Research
  • GEOMATIC ENGINEERING
  • Geomorphology and Regolith and Landscape Evolution
  • Glaciology

Resource constraints

Other constraints
This dataset is hosted by the University of Tasmania, on behalf of the Australian Centre for Excellence in Antarctic Science. This research was supported by the Australian Research Council Special Research Initiative, Australian Centre for Excellence in Antarctic Science (Project Number SR200100008).

Resource constraints

Linkage
https://licensebuttons.net/l/by/4.0/88x31.png

License Graphic

Title
Creative Commons Attribution 4.0 International License
Alternate title
CC-BY
Edition
4.0


>

Website
https://creativecommons.org/licenses/by/4.0/

License Text

Other constraints
Cite data as: King, M & Christoffersen, P (2024). Gridded SAM and ENSO coefficients derived from satellite altimeter data over the Antarctic Ice Sheet, 2002-2020 [Data set]. Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS). https://doi.org/10.25959/MKAIS-D424
Language
English
Character encoding
UTF8

Content Information

Content type
Physical measurement

Identifier

Code
ice elevation
Identifier
http://vocab.nerc.ac.uk/collection/P06/current/ULAA
Name
Metres

Distribution Information

Distribution format
  • netcdf

OnLine resource
DATA ACCESS - satellite altimetry data (3.54 GB zipped) [direct download]

Resource lineage

Statement
We make use of an existing gridded altimeter product (Nilsson et al. 2023) at 1920 m horizontal resolution and covering the period from April 1985 to December 2020 (Nilsson et al. 2022). We spatially down-sample this to 5 km horizontal resolution. To facilitate comparison with space gravimetry data we only make use of data from 2002 to the end of the record. The dataset contains monthly ice-sheet elevation-change data derived from a range of radar and laser altimeter missions; over the study period these are ERS-2, Envisat and CryoSat-2 and ICESat and ICESat-2. To reduce spatial noise we apply a Gaussian smoother with widths specified in later sections. For these, width is defined at the half height of the Gaussian function, consistent with the definition commonly used in GRACE data smoothing. We also use the existing COST-G RL01 Level-3 50 km gridded ice-mass change per surface area GRACE and GRACE-FO V0002 dataset obtained from http://gravis.gfz-potsdam.de/antarctica. We make use of data from March 2002 to December 2020, with the end point chosen to match the end of the altimetry dataset. The data are spaced approximately monthly and with a data gap of ~12 months between GRACE and GRACE-FO from mid-2017 to mid-2018. We compare the altimeter and GRACE data primarily with SAM and ENSO indices, with additional comparison to Amundsen Sea Low (ASL) indices in the Amundsen Sea region. For the ASL indices, we make use of both the absolute center pressure (ASLP) and longitude (ASLλ) within the ASL Index version 3.20210820-era5 based on monthly ERA5 reanalysis data. For SAM, we make use of the Marshall station index. For ENSO, we make use of the Nino3.4 index based on the HadISST1 dataset (Rayner 2003) and use a 6-month lag. We normalised each index with the mean and standard deviation computed over 1971-1999 inclusive, then cumulatively summed them, limited them to the data period, and then renormalized to produce SAMΣ, ENSOΣ, ASLPΣ, and ASLλΣ. We use ordinary linear least squares to solve for coefficients related to a constant, trend, harmonic terms for 1 and 2 cycles per year, and one for each of the SAM and ENSO terms.
Hierarchy level
Dataset
Hierarchy level
Dataset

Metadata

Metadata identifier
urn:uuid/cf3f6302-de8b-449b-80fb-cc757dcc454f

Language
English
Character encoding
UTF8

Distributor

IMAS Data Manager - Data Officer
Institute for Marine and Antarctic Studies
Private Bag 129
Hobart
Tasmania
7001
Australia
Institute for Marine and Antarctic Studies (IMAS) website >

Type of resource

Resource scope
Dataset
Name
IMAS Dataset level record
Metadata linkage
https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/cf3f6302-de8b-449b-80fb-cc757dcc454f

Point of truth URL of this metadata record

Date info (Creation)
2024-04-24T00:00:00
Date info (Revision)
2024-08-27T15:30:17

Metadata standard

Title
ISO 19115-3:2018
 
 

Overviews

Spatial extent

N
S
E
W


Keywords

El Nino Southern Oscillation (ENSO) GRACE gravimetry Southern Annular Mode (SAM) ice ice sheet satellite altimetry
AODN Discovery Parameter Vocabulary
ice elevation
AODN Instrument Vocabulary
altimeter
Australian and New Zealand Standard Research Classification (ANZSRC): Fields of Research
GEOMATIC ENGINEERING Geomorphology and Regolith and Landscape Evolution Glaciology
Global Change Master Directory Earth Science Keywords, Version 8.5
EARTH SCIENCE | CLIMATE INDICATORS EARTH SCIENCE | CLIMATE INDICATORS | CRYOSPHERIC INDICATORS | GLACIAL MEASUREMENTS | GLACIER ELEVATION/ICE SHEET ELEVATION EARTH SCIENCE | CRYOSPHERE | GLACIERS/ICE SHEETS | GLACIER MASS BALANCE/ICE SHEET MASS BALANCE

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Associated resources

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