Institute for Applied Physics "Nello Carrara"
Italian National Research Council
Department of Earth Observation 		transparent 
Inversion Problems and Data Assimilation



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Latest news on validation - July 2003

We are aware of the following problems in MIPAS Level 2 products that are currently distributed by ESA in near real time.

  • the thresholds for convergence criteria are not very stringent;
  • the values of the retrieved profile at the borders of the retrieval range are affected by the errors due to the assumption of the profile outside the retrieval range;
  • oscillations are present in the retrieved profiles.

Some tests have been performed at IFAC aimed to define new auxiliary data that allow to improve the quality of MIPAS Level 2 products:

  1. Extension of the retrieval range to the whole MIPAS measurement range. This would allow to reduce the error at the boundaries of the retrieval range due to the wrong assumption of the profile outside the retrieval range.
  2. Definition of new thresholds for the convergence criteria. This would allow to reduce the error in the retrieved profiles due to the fact the real convergence is not reached (this error will be referred in the text as ‘convergence error’)..
  3. Tuning of the variance of the ECMWF profiles used for the computation of the Initial Guess of the retrieval.

These improvements can be obtained at the expenses of an increased computing time.

The results of these tests are summarised here (31 July 2003).