Date: Wed, 3 Dec 2003 10:13:34 +0100 (Paris, Madrid)
From: Martine Feissel-Vernier 
To: Ramesh Govind , John Ries ,
    Pascal Willis ,
    Laurent Soudarin ,
    Jean-Michel Lemoine ,
    Suryia Tatevian ,
    Serguei Kuzin 
Cc: Gilles Tavernier ,
    Jean-Jacques Valette ,
    Jean-Pierre Granier ,
    Carey Noll ,
    Edouard Gaulué , feissel@ensg.ign.fr
Subject: Participation in the IDS-GRACE Campaign

Dear colleagues

We had a meeting with the IDS Central Bureau to prepare our contributions
to the 2003 Analysis campaign: products collection, comparisons,
evaluations. Our discussions led us to clarify the following aspects that
we ask you to take into account.

- Exact version of gravity fields considered:
  . the version of GRIM5 to be used is GRIM5-C1
  . the version of GGM01 to be used may be either GGM01C or GGM01S.

  I modified accordingly the webpage 
        IDS/events/ctrs_camp_2003.html

- SAA effect on the Jason data: Laurent Soudarin transmitted to me the
  following list of stations that are affected and should be deweighted or
  not considered in the analyses. He originally obtained it from Pascal
  Willis. The stations are the following.

        KRUB  AREB  ASDB  CACB  EASB  HBKB  HELB
        LIBB  SANB  GALA  PAQB  MAHB  PDMB  TRIB

  This list can be further discussed with other analysts if necessary.

- Treatment of the diurnal and semi-diurnal variations in polar motion
  that are due to the oceanic tides: the analysts are requested to follow
  the IERS conventional exchange procedure, namely that the provided
  coordinates of the pole do not contain these variations. A correction
  model is available in the  IERS Conventions (1996) at
        www.iers.org/iers/products/conv

- Polar motion rates: my proposal is that they are NOT estimated, as a
  first step. I would suggest that the impact of estimating them be part
  of a second step.

- Epoch of the weekly products: it is requested that the epoch be the
  central date of the data involved.

- When submitting your results to the IDS Data centers, please provide a
  "ccc.snx.readme" file, to be stored at the upper level of the
  /2003campaign directory. This file is necessary for any user to
  understand what he will find in the center's subdirectory. It comes in
  addition to the analysis description files "ccctuVV.snx.dsc". See
        IDS/doc/struct_dc.html#p7.

- I will maintain a webpage for the monitoring of the analysis campaign:
        IDS/events/update_camp_2003.html
  This page will not be advertised publicly. It will contain details on
  the exchange of information and progress of actions. 

- Please send a message to Jean-Jacques Valette and I when you upload a
  solution at one of the IDS Data Centers.

- Don't hesitate to start any discussion on data analysis you feel useful.
  We can use the mailing list of this message for that. Feel free to add
  other names to it.

An IDS meeting is tentatively planned on 3-5 May 2004 in Paris, right
after the EGU General Assembly in Nice. It would cover general matters
concerning the evolution of the IDS. One part of it would be devoted to
the discussion of the analysis campaign.

Thanking you for your participation.
Martine Feissel-Vernier
-- 
  Martine Feissel-Vernier               Internet:     feissel@ensg.ign.fr
  Observatoire de Paris and
  Institut Geographique National        Telephone:    33 (0) 1 64 15 32 83
  ENSG/LAREG     			Fax:          33 (0) 1 64 15 32 53
  8 Av. Blaise Pascal, Champs sur Marne
  77455 Marne la Vallee Cedex 2, France
--