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dorismail               16-May-2012 17:14:24 Message No 0823
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Author: Cerri Luca <Luca.Cerri@cnes.fr>
Subject: New delivery of the ENVISAT 2.2 dataset (up to arc 255)


Dear Doris analysts,

you might remember that in 2007 the measurements of Jason-1 were redelivered to the IDS 
to improve the computation of the ionospheric correction field. 
(See Doris Mail 498 ftp://ftp.ids-doris.org/pub/ids/dorismail/dorismail.0498 , May 25 2007)
The DORIS/SLR time bias issue was also corrected by this redelivery.

For the same reason, we take advantage of the recent GDR-C and GDR-D orbit 
reprocessing campaigns to redeliver the Envisat measurements to the IDS. 
This redelivery concerns 
arcs 001-255     - as since arc 256 the ionospheric field is corrected
arcs 901-907,910 - measurements available prior to arc 001, never delivered before

Besides the explanation already given in DorisMail 498, 
you should be aware of some additional facts :

1) In general you will see that the number of measurements increases 
   (both edited and valid measurments), partly due to the improvement 
   in the ionospheric correction field (see DorisMail 498) , and partly
   due by the significant effort performed by the CCI team 
   (the DORIS Instrument Control Center at CLS) to recover previously lost Envisat 
   measurements 

2) Unfortunately, this recovery effort could not prevent few beacons in the early 
   Envisat arcs from being lost, due to some configuration problems in the decommutations 
   of Envisat TM Data packets 

3) For some arcs the, definition of the arc start and end dates have changed in order to simplify 
   our POD processing (to include or exclude maneuvers for example). This will also change the 
   content of the file and the ftp://cddis.gsfc.nasa.gov/doris/data/en1/en1.files file should be updated. 

4) As for Jason1, the Envisat DORIS/SLR time bias should also be corrected 
   (on average) in this redelivery

These files are available on the IDS DATA Centers (CDDIS and IGN), at the usual locations.

I hope that you will be able to make good use of this redelivered data,

Best regards,

Luca, on behalf of CNES POD Team


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