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Fundamental Data Records for Altimetry [ALT_FDR___]

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The dissemination service provides data generated within the ESA FDR4ALT project.

The data is collection based and allows data browsing and download via treeview, filename or advanced catalogue search.

Data download is available via HTTPS, including bulk download functionality. ESA internal users can use their ESAAD account to access the HTTPS Dissemination Service.

Access to ftps://hm-lbr-ds.eo.esa.int is available via common FTP clients using “implicit FTP over TLS” and your own EO Sign In credentials. For internal ESA users the ESAAD account cannot be used for FTP access.

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Description

This dataset is a Fundamental Data Record (FDR) resulting from the ESA FDR4ALT project.

The Fundamental Data Record for Altimetry V1 products contain Level 0 and Level 1 altimeter-related parameters including calibrated radar waveforms and supplementary instrumental parameters describing the altimeter operating status and configuration through the satellite lifetime.

The data record consists of data for the ERS-1, ERS-2 and Envisat missions for the period ranging from 1991 to 2012, and bases on the Level 1 data obtained from previous ERS REAPER and ENVISAT V3.0 reprocessing efforts incorporating new algorithms, flags, and corrections to enhance the accuracy and reliability of the data.

For many aspects, the Altimetry FDR product has improved compared to the existing individual mission datasets:

  • New neural-network waveform classification, surface type classification, distance to shoreline and surface flag based on GSHHG
  • Instrumental calibration information directly available in the product
  • Improved Orbit solutions
  • Correction of REAPER drawbacks (i.e., time jumps and negative waveforms)

The FDR4ALT products are available in NetCDF format. Free standard tools for reading NetCDF data can be used.
Information for expert altimetry users is also available in a dedicated NetCDF group within the products.

Please consult the FDR4ALT Product User Guide before using the data.

The FDR4ALT datasets represent the new reference data for the ERS/Envisat altimetry missions, superseding any previous mission data. Users are strongly encouraged to make use of these datasets for optimal results.

Details

DATA SET SPECIFICATIONS

Digital Object Identifier (DOI):
Spatial coverage:
90 N, -90 S, -180 W, 180 E
Temporal coverage:
1991-08-03 - 2012-04-08ERS-1 data are available from 3 August 1991 to 2 June 1996, ERS-2 data are available from 10 May 1995 to 2 July 2003, Envisat data are available from 14 May 2002 to 8 April 2012.
Date of launch:
ERS-1: 1991-07-17, ERS-2: 1995-04-21, Envisat: 2002-03-01
Operators:
ESA
Mission status:
Completed
Orbit height:
800 km
Orbit type:
Sun-synchronous
Swath width:
5 - 1150 km

PROCESSING LEVEL

Level 1

APPLICABLE TERMS & CONDITIONS

Utilisation of this data is subject to ESA's Earth Observation Terms and Conditions.

READ T&C

DATA CITATION

European Space Agency, 2023, FDR4ALT Fundamental Data Records for Altimetry. Version 1.0.

RESOURCES

Product Document

FDR4ALT Completeness Report: ALT Products

Product Document

Download
Product Document

FDR4ALT Product Validation Report: FDR

Product Document

Download
Website

FDR4ALT Project Website

Website

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Product Specification

FDR4ALT Products Requirements and Format Specification

Product Specification

Download
User Guide

FDR4ALT Product User Guide

User Guide

Download
Detailed Processing Model

FDR4ALT Detailed Processing Model

Detailed Processing Model

Download
Product Document

FDR4ALT Uncertainty Characterisation Report

Product Document

Download
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