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 UAA25243 for ; Fri, 10 Jun 2005 20:55:35 +0200 Received: by hector.cls.fr (Postfix) id B89121D9FC; Fri, 10 Jun 2005 18:55:35 +0000 (GMT) Delivered-To: ids.analysis.forum@cls.fr Received: from rly11e.srv.mailcontrol.com (orange-103.cls.fr [62.161.32.14]) by hector.cls.fr (Postfix) with ESMTP id 03219133C8D for ; Fri, 10 Jun 2005 18:55:35 +0000 (GMT) Received: from nmta2.jpl.nasa.gov (nmta2.jpl.nasa.gov [137.78.160.215]) by rly11e.srv.mailcontrol.com (MailControl) with ESMTP id j5AItS5N003662 for ; Fri, 10 Jun 2005 19:55:29 +0100 Received: from xmta1.jpl.nasa.gov (xmta1.jpl.nasa.gov [137.78.160.144]) by nmta2.jpl.nasa.gov (Switch-3.1.7/Switch-3.1.7) with ESMTP id j5AItS3l012901 for ; Fri, 10 Jun 2005 11:55:28 -0700 Received: from [128.149.70.153] (mac01120073755.jpl.nasa.gov [128.149.70.153]) by xmta1.jpl.nasa.gov (Switch-3.1.7/Switch-3.1.7) with ESMTP id j5AItRc2021640 for ; Fri, 10 Jun 2005 11:55:27 -0700 Mime-Version: 1.0 Message-Id: Date: Fri, 10 Jun 2005 11:55:23 -0700 To: IDS_Analysis_Forum From: Pascal Willis Subject: break estimation / computing discontinuities and formal errors Content-Type: multipart/alternative; boundary="============_-1093692771==_ma============" X-Source-IP: mac01120073755.jpl.nasa.gov [128.149.70.153] X-Source-Sender: Pascal.R.Willis@jpl.nasa.gov X-AUTH: Internal IP X-Modified-HTML: 6 X-Mailcontrol-Inbound: l4EzehkE5wet4YVA0q213v5tlkt3OnCB16COtuSiUsY= X-Spam-Score: -3.8 X-Scanned-By: MailControl A-05-01-01 (www.mailcontrol.com) X-Validation-by: ries@csr.utexas.edu This is a multi-part message in MIME format... --============_-1093692771==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" Content-Disposition: inline Hi Martine, Could I suggest that add to your table for all considered breaks (either detected by at least 1 center or by you or by another source such as GPS) and for all available time series, the estimated discontinuity as well as its formal error. I will take Fairbanks (Nov 3, 2002 Earthquake) as an example to better explain my proposal. For Fairbanks in latitude, when I estimate the discontinuity from the STCD files available at CDDIS, I get : DORIS monthly LCA -36.5 +/- 43.6 mm DORIS weekly IGN -51.4 +/- 14.7 mm (using the FAIA data after 1996/1/1 and all the FAIB data) Here are 2 recent GPS result for the Fairbanks stations (FAIR) GPS daily JPL -65.3 +/- 6.5 mm (using 2002-2003 data only) (see http://sideshow.jpl.nasa.gov/mbh/all/FAIR.html) GPS daily SOPAC -54.76 +/- 3.26 mm (see http://sopac.ucsd.edu/cgi-bin/sector.cgi) I guess these numbers explain why the LCA group does not detect the discontinuity. But their estimation is also compatible with the break of -5 cm (within the formal errors, after reweighting). By the way, it is not clear to me why the standard deviations are so different from the 2 solutions. A careful cross-examination of these results is required. If you just put "yes" or "no" in your table, people can think that the 2 DORIS time series disagree. In fact, this is not the case. You can see it clearly when looking at the estimated discontinuities and the formal error per AC. I would encourage you to do similar analysis for all stations for which a break has been proposed before starting the discussion Each AC could then react and I am sure that we will converge more rapidly and learn some more new things Thanks in advance Pascal NB: It also seems that the velocity of the Fairbanks station could different after the Earthquake. This may be difficult to see with DORIS alone, but I think we could use extra information as well. -- Pascal Willis Jet Propulsion Laboratory, MS 238-646 Ph : 1-818-393-4748 4800 Oak Grove Drive FAX: 1-818-393-4965 Pasadena CA 91109 Em : Pascal.R.Willis@jpl.nasa.gov --============_-1093692771==_ma============ Content-Type: text/html; charset="us-ascii" Content-Disposition: inline break estimation / computing discontinuities and formal er
Hi Martine,

Could I suggest that add to your table for all considered breaks (either detected by at least 1 center or by you or by another source such as GPS) and for all available time series, the estimated discontinuity as well as its formal error.

I will take Fairbanks (Nov 3, 2002 Earthquake) as an example to better explain my proposal.

For Fairbanks in latitude, when I estimate the discontinuity from the STCD files available at CDDIS, I get :

DORIS   monthly LCA     -36.5 +/- 43.6 mm
DORIS   weekly          IGN     -51.4 +/- 14.7 mm

(using the FAIA data after 1996/1/1 and all the FAIB data)

Here are 2 recent GPS result for the Fairbanks stations (FAIR)

GPS     daily           JPL     -65.3 +/- 6.5 mm (using 2002-2003 data only)

(see http://sideshow.jpl.nasa.gov/mbh/all/FAIR.html)

GPS     daily           SOPAC   -54.76 +/- 3.26 mm

(see http://sopac.ucsd.edu/cgi-bin/sector.cgi)

I guess these numbers explain why the LCA group does not detect the discontinuity. But their estimation is also compatible with the break of -5 cm (within the formal errors, after reweighting).

By the way, it is not clear to me why the standard deviations are so different from the 2 solutions. A careful cross-examination of these results is required.

If you just put "yes" or "no" in your table, people can think that the 2 DORIS time series disagree. In fact, this is not the case. You can see it clearly when looking at the estimated discontinuities and the formal error per AC.

I would encourage you to do similar analysis for all stations for which a break has been proposed before starting the discussion

Each AC could then react and I am sure that we will converge more rapidly and learn some more new things

Thanks in advance
Pascal

NB: It also seems that the velocity of the Fairbanks station could different after the Earthquake. This may be difficult to see with DORIS alone, but I think we could use extra information as well.
--
Pascal Willis
Jet Propulsion Laboratory, MS 238-646     Ph : 1-818-393-4748
4800 Oak Grove Drive                      FAX: 1-818-393-4965
Pasadena CA 91109                         Em : Pascal.R.Willis@jpl.nasa.gov


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