CMA - Altimeter Multi mission Centre - is the component of the SSALTO (Multi mission ground Segment for ALTimetry, Orbitography and precise localisation) ground segment from CNES (the French space agency), in charge of the processing and the verification of the altimetric and radiometric data from Jason-1 and Envisat missions. CMA is also designed to integrate easily other missions such as Jason-2 and to reprocess data such as Topex/Poséidon.

CLS tasks:

From 1998, CLS has been in charge of the definition and specifications of processing and products for both Jason-1 and Envisat missions. Until 2001, CMA scientific and data management processing chains have been developed and validated by CLS before launches of Jason-1 (December 2001) and Envisat satellites (March 2002). Since 2001 and for the duration of these missions, CLS has been in charge, under CNES responsibility, of the operation, the maintenance of CMA and has been provided support to expertise activities of CMA project.

CMA functions:

• Production. CMA must ensure the regular production and check of users products, i.e. of the following main altimeter/radiometer geophysical products:
  • OSDR - Operational Sensor Data Record: This is a real-time product (Jason-1 only), which mainly contains near-real time wind/wave information, and which is used for marine meteorology (delay of less than 3 hours)
  • IGDR - Interim Geophysical Data Record: This is a geophysical product, available within 3 days, and used for operational oceanography
  • GDR - Geophysical Data Record: This product is similar to IGDR but it is built from a precise orbit (delay of one month)
   
  
• Verification. Besides users products, "verification" products are built for both missions (CalVal): The distribution of IGDR and GDR products is authorised or not depending on the results of the systematic interpretation of the following verification products.
  • "Crossover": This product contains sea level and geophysical data at the crossover points (points where two passes are crossing)
  • "Corrected Sea Surface height" (CORSSH): This product contains along track sea surface height data, corrected for geophysical effects (study of oceanic or stationary geophysical phenomenon's or very low variation phenomenon's) "Sea Level Anomaly" (SLA): This product contains along track residual sea surface height data (oceanic variability study)
  CORSSH and SLA products are distributed by Aviso User Services.
   
  
• Expertise. CMA must finally ensure expertise functions such as the products quality assessment, the follow-up and the improvement of algorithms, the long-term monitoring of instruments (see Instrumental expertise)

Users:

More: