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    24-Jul-2014
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2.7.2 RA2/MWR Level 2 Products

The Level 2 products are the science products that are user-oriented. The Level2 product family is composed of three types specifically design for different applications. It basically consists of three main products: GDR (Geophysical Data Record), SGDR (Sensor GDR) and MAR (Marine Abridged Records). In the following paragraphs the definition of the products is first given. It is followed by the description of the structure.

2.7.2.1 Definition

The GDR Products are:

  • FDGDR product : The RA-2 / MWR level 2 Fast Delivery GDR (or FDGDR) products are generated by the Near Real Time processing from level 1b unconsolidated products, using predicted auxiliary data. "Unconsolidated" means parameters which do not account for the final instrumental calibration data.
  • IGDR product : The RA-2 / MWR level 2 Interim GDR (or IGDR) products are generated by the Off-Line processing, within a few days (3 to 5), from level 1b unconsolidated products, using restituted auxiliary data (meteorological fields, pole location, DORIS ionospheric data) and a DORIS preliminary orbit.
  • GDR product : The RA-2 / MWR level 2 GDR products are generated by the Off-Line processing, within a few weeks (3 to 4), from level 1b consolidated products, using the best restituted auxiliary data (meteorological fields, solar activity indexes, pole location, platform data, DORIS ionospheric data) and a DORIS precise orbit. "Consolidated" means parameters which account for the updated instrumental calibration data.

 

The SGDR Products are :

  • SGDR product : The SGDR is essentially the same product as the GDR, with waveforms added to the product. The SGDR is generated from the consolidated Level 1B (waveforms corrected for long term instrument variations) and from the GDR (same geophysical corrections).

 

The MAR Products are :

  • A MAR product contains an ocean oriented (only ocean retracker) subset of the FD/I/GDR. It is made available for near real time or quasi near real time meteorological and oceanographic applications. The subsets are called, respectively, FDMAR and IMAR.

 

The FDGDR and FDMAR products correspond to a segment of the orbit, corresponding to the data downlinked over a receiving station, while the IGDR, GDR, SGDR and IMAR products span half an orbit, i.e. a pass from pole to pole.

Note that the FDMAR products are also made available in BUFR format through the PDS for the METEO offices.

The product tree is given in the following figure.

 

 

2.7.2.2 Structure

All these products follow the PDS structure which consists of a MPH, a SPH and one or several MDS. Below is given the structure for each of the products listed above.

For the FDGDR, IGDR, GDR products the structure is the following :

  • MPH/SPH/RA2 MDS/MWR MDS

 

For the SGDR product the structure is the following :

  • MPH/SPH/RA2 MDS/MWR MDS/Average Waveforms MDS/Individual Waveforms MDS

 

For the FDMAR and IMAR product the structure is the following :

  • MPH/SPH/RA2 MDS

2.7.2.3 Level 2 RA2/MWR SPH

The SPH is an ASCII header and has the same format for every product. The fields of the SPH are of the following types:

  • RA-2 Time Information
  • RA-2 Positioning Information
  • RA-2 Quality Information
  • RA2 Subsystem Identification
  • RA-2 Processing Information
  • MWR Time Information
  • MWR Positioning Information
  • MWR Quality Information
  • DSDs for included Data Sets
  • DSDs for referenced files

2.7.2.4 Level 2 RA2 MDS in FDGDR, IGDR and GDR

The RA-2 MDS is composed of several MDSRs (1 MDSR every 1.114s). The records in the MDS contain 1 Hz and 18 Hz data. Within a MDSR the fields are of the following types :

  • Time Information
  • Geolocation Information
  • Quality Information
  • Orbit Information
  • Range Information
  • Range Corrections Information
  • Significant Wave Height Information
  • Backscatter Information
  • Backscatter Corrections Information
  • Off-nadir Angle Information
  • Geophysical Information
  • MWR Information
  • Flags and Other Quality Information

2.7.2.5 Level 2 RA2 MDS in FDMAR and IMAR

The RA-2 MDS for FDMAR and IMAR products is a subset of the GDR product which contains only the 1 Hz data and results of the ocean retracker. The type of information found is the same as the RA-2 MDS in the GDR products.

2.7.2.6 Level 2 MWR MDS

The format of the MWR MDS is identical to that described in Level 1b MWR MDS 2.6.3.7.

2.7.2.7 Level 2 Averaged Waveforms MDS

The RA-2 Average Waveform MDS is composed of several MDSRs. The records in the MDS contain 18 Hz data. Within a MDSR the fields are of the following types :

  • Time Information
  • Quality Information
  • Waveform Information
  • Power Information

2.7.2.8 Level 2 Individual Waveforms MDS

The format of the Individual Waveform MDS is identical to that described in Level 1b RA2 individual echoes waveforms MDS 2.6.3.5.


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry