X-Sympa-To: ids.analysis.forum Received: from hector.cls.fr (osis.cls.fr [62.161.32.21]) by hermes.cls.fr (8.9.3/8.9.3) with ESMTP id GAA01211 for ; Thu, 19 Oct 2006 06:54:07 GMT Received: by hector.cls.fr (Postfix) id B21BA10B8ED; Thu, 19 Oct 2006 05:53:58 +0000 (GMT) Delivered-To: ids.analysis.forum@cls.fr Received: from cluster-e.mailcontrol.com (orange-103.cls.fr [62.161.32.14]) by hector.cls.fr (Postfix) with ESMTP id 14FD7840F for ; Thu, 19 Oct 2006 05:53:57 +0000 (GMT) Received: from puuoo.gsfc.nasa.gov (puuoo.gsfc.nasa.gov [128.183.109.10]) by rly01e.srv.mailcontrol.com (MailControl) with ESMTP id k9J5rRPm008639 for ; Thu, 19 Oct 2006 06:53:29 +0100 Received: by puuoo.gsfc.nasa.gov (Postfix, from userid 48) id DF2ABCDEA3; Thu, 19 Oct 2006 01:53:26 -0400 (EDT) Received: from 58.169.55.239 (SquirrelMail authenticated user flemoine) by puuoo.gsfc.nasa.gov with HTTP; Thu, 19 Oct 2006 05:53:26 -0000 (GMT) Message-ID: <52694.58.169.55.239.1161237206.squirrel@puuoo.gsfc.nasa.gov> Date: Thu, 19 Oct 2006 05:53:26 -0000 (GMT) Subject: [Forwarded: Re: Jason models] From: "Frank Lemoine" To: ids.analysis.forum@cls.fr Reply-To: Frank.Lemoine@gsfc.nasa.gov User-Agent: SquirrelMail/1.4.7-4.fc4 MIME-Version: 1.0 Content-Type: multipart/mixed;boundary="----=_20061019055326_63060" X-Priority: 3 (Normal) Importance: Normal X-Mailcontrol-Inbound: 9T0eCKY0PlK8m9gA9DBkkRwHPXXURTA5THfcd2uWoYQ= X-Spam-Score: 1.2 X-Scanned-By: MailControl A-07-06-65 (www.mailcontrol.com) on 10.69.0.111 X-Validation-by: frank.lemoine@gsfc.nasa.gov ------=_20061019055326_63060 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit ---------------------------- Original Message ---------------------------- Subject: Re: Jason models From: "John C. Ries" Date: Thu, October 19, 2006 12:28 am To: jean-paul.berthias@cnes.fr Cc: Frank.Lemoine@gsfc.nasa.gov Scott.B.Luthcke@nasa.gov "Nikita Zelensky" "Dr. Erricos C. Pavlis" Bruce.J.Haines@jpl.nasa.gov "Pascal Bonnefond" "Cerri Luca" "Mercier Flavien" "Laurent Soudarin" Richard.Biancale@cnes.fr -------------------------------------------------------------------------- At 4:50 PM +0200 10/17/06, Jean-Paul Berthias wrote: >Hi John, > >In your last Email you propose to >>1)* We adopt the IERS2003 values for C21/S21 at epoch 2000.0 as >>well as the rates. These are consistent with the mean pole and >>rates adopted for the pole tide, also in the standards.* Because >>the rates were not used for EIGEN-GL04C, this is the only way I >>see to ensure consistency with the pole tide model. > >Just to make sure that we all understand the same thing, the >standards tell us (at the beginning of chapter 6) how to compute the >C21/S21 and associated rates from the values of the mean pole and >C20, C22 and S22. We should adopt the mean pole (and mean pole rate >from the standards), but the C20, C22 and S22 of the gravity model >that we plan to use (EIGEN-GL04C). > >When we do that we obtain values of C21/S21 slightly different than >those given in the standards which are valid for EGM96. The EIGEN >based standards are > >C21 = -2.36e-10 >S21 = 15.12e-10 >C21dot = -0.341e-12 >S21dot = 1.602e-12 > Hi Jean-Paul, I found some older emails where you had raised related questions about C21/S21, and I'm not sure what conclusion we had come to. But perhaps now we can try to clarify this. When I calculate C21/S21 from the standards, using EGM96 (C20 mapped to epoch 2000), I get C21/S21: -2.23E-10 1.447E-09 rates: -0.337E-11 1.606E-11 My calculation differs by just 1 from IERS2003 in the last digit for S21; otherwise I match it. The small difference for S21 may just have been some rounding. The rates are calculated by simply replacing xbar and ybar with xbardot and ybardot from chapter 7 and ignoring the C22/S22 contributions. If the C22/S22 contributions are included, the rates become -0.341E-11 1.602E-11 which matches your calculation for the rates. Not enough difference to worry about and probably well under the uncertainty in the determination of the mean pole rates. But it is inconsistent, and I'm not sure why the C22/S22 contributions were ignored for the rates in the standards. The estimated uncertainty in C21/S21 is ~2e-11 from EIGEN-GL04C. The difference in the rate calculation (with and without C22/S22) is 4e-14. It would take hundreds of years for the difference to be significant. When I use EIGEN_GL04C's values for C20, C22 and S22, I get the same numbers. This is expected since C20, C22 and S22 differ only in the fourth or fifth digit at most. There must be some error in your calculations. I can't duplicate it. I'm attaching a simple piece of code so that you can check my calculations. My conclusion is that the IERS2003 standards are more or less model independent. The difference in the calculation of the rates is unimportant, but perhaps we should propose they make it consistent, since it is otherwise a bit confusing. See ya, JR Cliquez sur l'url suivante https://www.mailcontrol.com/sr/0LeEc5rrCG0sVg59ERplkj5J+qAueEIMNVXfcdXCNQZArOXrnaymyRMyqT9wXpGKFca9Q1zmxOaqIC9L98lwFfeZdCfwhGZRO+lOJsZmdP4DHvwIKbMMfxBO6erZforkwvEU6LC2IChRzObtQiRJE5LzgHgGYw1HZlbWBfOxfUckfgQnFmoME5jwbafGyXivg+0tVwW8yYz5x1eRwRYjKBjrCmy1uuk2 si ce message est indésirable (pourriel). ------=_20061019055326_63060 Content-Type: application/applefile; name="%" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="%" AAUWBwACAAAAAAAAAAAAAAAAAAAAAAAAAAMAAAADAAAAPgAAAAgAAAAJAAAA RgAAACAAAAAIAAAAZgAAABBwcm9nLnR4dAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAADMk6YAzJOmBLbQwADMk8zA== ------=_20061019055326_63060 Content-Type: application/octet-stream; name="prog.txt" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="prog.txt" ICAgICAgcHJvZ3JhbSBkdW0KYwpjLi5lZ205NgogICAgICBjMjA9LTQuODQx NjkzODE5NTAyNUUtMDQKICAgICAgYzIyPSAyLjQzOTE0MzUyMzk4MDBFLTA2 CiAgICAgIHMyMiA9IC0xLjQwMDE2NjgzNjU0MDBFLTA2CmMuLmdmejA0Ywog ICAgICBjMjA9LTQuODQxNjk0NzA4OTc0NkUtMDQKICAgICAgYzIyID0gMi40 MzkzNjQ1NjYxNTYzRS0wNgogICAgICBzMjIgPSAtMS40MDAyODU5NDE0MDQz RS0wNgogICAgICB4YmFyID0gMC4yNjJlLTYKICAgICAgeWJhciA9IDEuNzNl LTYKICAgICAgeGJhcmRvdD0wLjAwMDgzCiAgICAgIHhiYXJkb3QgPSAoeGJh cmRvdC8zNjAwLjApLzU3LjI5NQogICAgICB5YmFyZG90PTAuMDAzOTUKICAg ICAgeWJhcmRvdCA9ICh5YmFyZG90LzM2MDAuMCkvNTcuMjk1CiAgICAgIGMy MSA9IHNxcnQoMy4wKSp4YmFyKmMyMC14YmFyKmMyMit5YmFyKnMyMgogICAg ICBzMjEgPSAtc3FydCgzLjApKnliYXIqYzIwLXliYXIqYzIyLXhiYXIqczIy CiAgICAgIHByaW50ICosJyAnCiAgICAgIHByaW50ICosJ0VJR0VOLUdMMDRD JwogICAgICBwcmludCAqLCdjMjEsczIxLCB3aXRoIGMyMi9zMjIgY29udHJp YnV0aW9ucycKICAgICAgcHJpbnQgMTAwMCxjMjEsczIxCiAgICAgIGMyMSA9 IHNxcnQoMy4wKSp4YmFyKmMyMAogICAgICBzMjEgPSAtc3FydCgzLjApKnli YXIqYzIwCiAgICAgIHByaW50ICosJyAnCiAgICAgIHByaW50ICosJ2MyMSxz MjEsIHdpdGhvdXQgYzIyL3MyMiBjb250cmlidXRpb25zJwogICAgICBwcmlu dCAxMDAwLGMyMSxzMjEKICAgICAgYzIxZG90ID0gc3FydCgzLjApKnhiYXJk b3QqYzIwCiAgICAgIHMyMWRvdCA9IC1zcXJ0KDMuMCkqeWJhcmRvdCpjMjAK ICAgICAgcHJpbnQgKiwnICcKICAgICAgcHJpbnQgKiwnYzIxZG90LHMyMWRv dCwgd2l0aCBjMjIvczIyIGNvbnRyaWJ1dGlvbnMnCiAgICAgIHByaW50IDIw MDAsYzIxZG90LHMyMWRvdAogICAgICBjMjFkb3QgPSBzcXJ0KDMuMCkqeGJh cmRvdCpjMjAteGJhcmRvdCpjMjIreWJhcmRvdCpzMjIKICAgICAgczIxZG90 ID0gLXNxcnQoMy4wKSp5YmFyZG90KmMyMC15YmFyZG90KmMyMi14YmFyZG90 KnMyMgogICAgICBwcmludCAqLCcgJwogICAgICBwcmludCAqLCdjMjFkb3Qs czIxZG90LCB3aXRob3V0IGMyMi9zMjIgY29udHJpYnV0aW9ucycKICAgICAg cHJpbnQgMjAwMCxjMjFkb3QsczIxZG90CiAxMDAwIGZvcm1hdCAoMXBlMTAu MixlMTAuMykKIDIwMDAgZm9ybWF0IChlMTAuMywxcGUxMC4zKQogICAgICBz dG9wCiAgICAgIGVuZA== ------=_20061019055326_63060--