Change to processing standards of SARAL OGDRs

The processing standards of the near-realtime SARAL/AltiKa altimeter products, known as Operational Geophysical Data Records (OGDR), will be updated on 26 February.

Friday, 07 February 2020

This change is taking place to conform to the standards that are also set in place for the next generation of Jason-3 products, the future Sentinel-6 products, as well as future reprocessings of TOPEX/Poseidon, Jason-1 and Jason-2 products.

While products of some of these missions will have their own specificities, they are consistent and comparable. SARAL/AltiKa is the first of said missions to be transferred from the older GDR-T (which was consistent with GDR-D) to the GDR-F standard.

The transition between SARAL GDR-T and GDR-F includes approximately 50 improvements. Some of those upgrades have an impact on one or several GDR variables, others will only in the global attributes. Globally, around 45 GDR-T existing variables are impacted, and 43 variables are added. Please consult the following documents for details:

SARAL/AltiKa GDR-F User Guide

SALP Products Specification — Volume 20: AltiKa / SARAL User Products

Products with the new standard can be recognised, for the netCDF files, by the file name starting with "SRL_OP<N/R>_2PfS" where <N/R> depends on whether the products are 'Native' or 'Reduced'. The first products to follow these new standards will be released on 26 February.

Sample files, in both netCDF and BUFR formats, generated with the new standards, are available on our FTP server:

For more information, contact our User Service Helpdesk.

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