The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) and principal investigator Stephen Leroy of JANUS Research Group have released Global Navigation Satellite System Radio Occultation (GNSS RO) datasets. This data release includes 72 different products from 15 different GNSS RO receivers (or constellations of receivers) processed at four different GNSS RO retrieval/processing centers. The data from different processing centers have been reformatted to have a common Climate and Forecast Metadata Conventions (CF) compliant format.
The algorithm was developed with funding from the NASA ACCESS 2019 program and the NASA Supplements for Open Science Support. These are the version 2.0 GNSS RO products; version 1.1 is available through the AWS Registry of Open Data.
GNSS RO data undergoes processing that is radically different from that of most atmospheric sounders, but it can still be categorized by its processing step:
- uncalibrated data, as provided by the satellite instrument with communication information stripped, are Level 1a (not part of this release);
- calibrated data, wherein the clock biases of the transmitters and receivers are removed and precise orbits determined are Level 1b;
- extremely high vertical-resolution profiles of RO bending angle and microwave refractivity are Level 2a; and
- profiles of temperature, pressure, and specific humidity on a coarser vertical grid are Level 2b.
As of this writing, products are still being added to the archive. This initial release is complete for all processing levels of the COSMIC-1 data sets from four different processing centers. After all of the products in this initial release are complete for the available data through July 2025, we will begin forward processing for the missions that are still actively producing data.
For more information about these products please see the README document and the Algorithm Theoretical Basis Document (ATBD).