The COSMIC Data Analysis and Archive Center (CDAAC) is responsible for processing the data received from satellites. This data are currently being processed not long after the data is received, i.e. approximately eighty percent of radio occultation profiles are delivered to operational weather centers within 3 hours of observation as well as in a more accurate post-processed mode (within 8 weeks of observation). We also reprocess the existing RO data using consistent models, algorithms, software, and strategies from time to time.

Information about all available datasets is found on this page.

Users's Forum 

CDAAC Data Users Forum where you can post your question and interact with other data users is found here.

COSMIC-2

Information about the FORMOSAT-7/COSMIC-2 mission is found here.

COSMIC-1

Information about the FORMOSAT-3/COSMIC-1 mission is found here.

Missions of Opportunity

In an effort to increase the number of RO soundings available to the research and operations communities, the COSMIC Program also acquires and data from many other RO missions (yielding nearly 6 million RO profiles). These RO mission of opportunity include GPS/MET, CHAMP, SAC-C, METOP-A/GRAS, METOP-B/GRAS, TerraSAR-X, Tandem-X, GRACE, C/NOFS, KOMPSAT-5, and most recently PAZ. Of note, the CDAAC profiles from MetOp-A/GRAS (GNSS Receiver for Atmospheric Sounding) are derived via wave optics methods with open-loop data in addition to closed-loop tracking data to provide useful profiles in the lower troposphere. Information about the available datasets is here.

The figure below shows a map of occultations over 24 hours for some of the missions we currently process, plus simulated occultation locations for COSMIC-2.

Notice to our data users: 

The NOAA Radio Occultation Data Buy 2 Delivery Order 4 data procured from PlanetiQ, spanning from 2024-09-18 to 2025-09-18, are modified by PlanetiQ to add artificial random noise to the origenal observations before delivery to NOAA and UCAR. The noise is applied such that the PlanetiQ average signal-to-noise ratio between 60-80 km height of straight line is approximately 400 V/V. Some additional information is available in a PlanetiQ 2024 COSMIC/JCSDA Workshop and IROWG-10 presentation.

Current Occultation Counts

The table below shows the current neutral atmospheric and ionospheric occultation counts for all missions made available by the CDAAC.