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	    NOAA STAR GNSS-RO Retrieval Products Release
            ============================================

                            6 Feb 2025


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3 products in current stage

  1) STAR ROPP (v2.20u)
  2) STAR RFSI (v2.33 to v2.42)
  3) STAR 1Dvar (v3.2)


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1) STAR ROPP

  v2.0,  based on ROPP v10.0 default setting. Added pre-processing for C-2. Applied STAR quality control. 
         Data was released in June 2021 for:

      COSMIC-2 

  v2.20, based on STAR ROPP v2.0, with Amplitude threshold adjusted. Modified
         the input/output module to add the capability to interpolate orbit positions and signal
         transmission from the low time rate to the high time rate. Also added the capability 
         to process RO observations from multiple GNSS satellites, including
         GLONASS, GALILEO, and BeiDou, in addition to GPS, by updating the L1 and L2
         frequencies based on different GNSS systems. 
         Data was released in August 2023 for:

      COSMIC-2  
      PlanetiQ 
      Spire   
      KOMPSAT-5 
      PAZ  
      GRAS Metop-C 
      GRAS Metop-B
      GRAS Metop-A 
      COSMIC-1 
      TerraSAR-X
      TanDem-X

  v2.20u, the same to v2.20, with undulation value inserted. 
          Data was released in February 2025 for:

      COSMIC-2  
      PlanetiQ 
      Spire   
      KOMPSAT-5 
      PAZ  
      GRAS Metop-C 
      GRAS Metop-B
      GRAS Metop-A 
      COSMIC-1 
      TerraSAR-X
      TanDem-X


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2) STAR RFSI  

  v1.0, FSI developed by NOAA STAR to invert phase data to bending angle and refractivity profiles using the full spectrum inversion method. 
        Data was released in March 2021 for:

      COSMIC-2  

  v2.0, merged the FSI package to ROPP framework. Data was not released.
  
  v2.33, adjusted the cut-off height to avoid the contamination from low quality L2 phase data.  
         Data was released in March 2021 for:

      COSMIC-2  
      KOMPSAT-5 
      PAZ  
      TerraSAR-X
      TanDem-X

  v2.34, adjusted the cut-off height.  
         Data was released in January 2025 for:

      GRAS Metop-C 
      GRAS Metop-B
      GRAS Metop-A 

  v2.37, Degraded L2 data flag opt_DL2 was set to .false. for PlanetiQ.
         Data was released in August 2023 for:

      PlanetiQ 

  v2.42, adjusted the cut-off height to deal with the low LEO satllite orbit.  
         Data was released in January 2025 for:

      Spire   


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3) STAR 1Dvar

  v1.0, developed by NOAA STAR to retrieve atmospheric pressure, temperature and water vapor profiles from refractivity 
        obtained in Radio Occultation (RO) observations. Use NCEP GFS 6h forecast as first guess. 
        Data was eleased in Sep 2022 for:

      COSMIC-2

  v2.0, based on v1.0. SR correction option added. Retrieval from bending angle option added. Data was not released.
  v3.0, based on v2.0. ERA5 06h forecast as first guess option added. Data was not released.
  v3.1, imigrated v3.0 package from STAR server to UMD servers. Data was not released.

  v3.2, based on v3.1. Do retrieval from refractivity. Use ECMWF ERA5 6h forecast as first guess. H_switch adjusted. 
        Data was released in Nov 2023 for:

      COSMIC-2  
      PlanetiQ 
      Spire   
      KOMPSAT-5 
      PAZ  
      GRAS Metop-C 
      GRAS Metop-B
      GRAS Metop-A 
      COSMIC-1 
      TerraSAR-X
      TanDem-X