[OpenMadrigal-developers] F10.7 Multiday average proposal
John Holt
jmh at haystack.mit.edu
Fri Oct 20 15:17:22 EDT 2006
I agree with Sunrong's reasoning but, unfortunately, the acausal
definition of F10.7bar is now the one in common use. Phil's definition,
as I understand it, retains that definition for all but the most recent
40 days and converges on the common definition after 40 days. The only
CEDAR definiton I could find is not explicit.
John
> Date: Fri, 20 Oct 2006 15:07:17 -0400
> From: Shunrong Zhang <shunrong at haystack.mit.edu>
> User-Agent: Thunderbird 1.5.0.7 (X11/20060909)
> To: Open Madrigal developers list <openmadrigal-developers at openmadrigal.org>
> Subject: Re: [OpenMadrigal-developers] F10.7 Multiday average proposal
> Content-Transfer-Encoding: 7bit
> X-BeenThere: openmadrigal-developers at openmadrigal.org
> X-Mailman-Version: 2.1.5
> List-Id: Open Madrigal developers list
<openmadrigal-developers.openmadrigal.org>
> List-Unsubscribe:
<http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers>,
<mailto:openmadrigal-developers-request at openmadrigal.org?subject=unsubscribe>
> List-Archive: <http://www.haystack.mit.edu/pipermail/openmadrigal-developers>
> List-Post: <mailto:openmadrigal-developers at openmadrigal.org>
> List-Help:
<mailto:openmadrigal-developers-request at openmadrigal.org?subject=help>
> List-Subscribe:
<http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers>,
<mailto:openmadrigal-developers-request at openmadrigal.org?subject=subscribe>
> X-DSPAM-Result: Innocent
> X-DSPAM-Probability: 0.000000
> X-DSPAM-Signature: 45391edb37962061126357
>
> If we totally redefine Fbar to be for the last 81 days, that is fine;
> but I think what Phil suggested was "for any day less than 40 days in
> the past, we calculate FBAR as an average over the most recent 81 days.
> " That sounds to me that you still use the old definition for any day
> greater than day 40 days in the past. I wanted to say that there should
> not be two definitions for one parameter. From modeling point of view, I
> agree with John that "ending with the day of interest will tend to give
> a somewhat better prediction". That was why I suggested my option (2)
> for a new F107 index that is an average over the past 81 days and is
> always available.
>
> Shunrong
>
>
> John Holt wrote:
> > Phil's suggestion seems reasonable. In the context of a model, the
> > definition of F10.7bar as a centered average is an absurdity,
> > obviously. In the "old" days we always used the 81 days ending with the
> > day of interest, but at some point it apparently became more common to
> > forget causality and use a centered average (I have seen 27 days, 54
> > days, 81 days 90 days and one year) and a variety of filter functions
> > causal and not. Unfortunately, in my view, causal filters fell out of
> > favor. Had they not, we would not have had this problem and would have
> > been consistent with the laws of physics as well, which is no small
> > thing. I suspect, by the way, that using the 81 days ending with the
> > day of interest will tend to give a somewhat better prediction than
> > using a centered average, even though the model was computed using a
> > centered average.
> >
> > John
> >
> > ________________________________________________________________________
> > | |
> > | John M. Holt tel: 781-981-5625 |
> > | Principal Research Scientist fax: 781-981-5766 |
> > | MIT Haystack Observatory email: jmh at haystack.mit.edu |
> > | Route 40 WWW: http://www.haystack.edu/ |
> > | Westford, MA 01886 |
> > | USA |
> > |________________ Ni h-eibhneas gan chlainn domhnaill _________________|
> >
> >
> >
> >> Date: Fri, 20 Oct 2006 11:53:15 -0400
> >> From: Bill Rideout <brideout at haystack.mit.edu>
> >> User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.13)
Gecko/20060417
> >> X-Accept-Language: en-us, en
> >> To: openmadrigal-developers at openmadrigal.org
> >> Content-Transfer-Encoding: 7bit
> >> Subject: [OpenMadrigal-developers] F10.7 Multiday average proposal
> >> X-BeenThere: openmadrigal-developers at openmadrigal.org
> >> X-Mailman-Version: 2.1.5
> >> List-Id: Open Madrigal developers list
> >>
> > <openmadrigal-developers.openmadrigal.org>
> >
> >> List-Unsubscribe:
> >>
> > <http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers>,
> >
<mailto:openmadrigal-developers-request at openmadrigal.org?subject=unsubscribe>
> >
> >> List-Archive:
<http://www.haystack.mit.edu/pipermail/openmadrigal-developers>
> >> List-Post: <mailto:openmadrigal-developers at openmadrigal.org>
> >> List-Help:
> >>
> > <mailto:openmadrigal-developers-request at openmadrigal.org?subject=help>
> >
> >> List-Subscribe:
> >>
> > <http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers>,
> > <mailto:openmadrigal-developers-request at openmadrigal.org?subject=subscribe>
> >
> >> X-DSPAM-Result: Innocent
> >> X-DSPAM-Probability: 0.000000
> >> X-DSPAM-Signature: 4538f138202497825867
> >>
> >> Phil Erickson has suggested we modify out definition of the F10.7
> >> Multiday average (FBAR). Right now this is an 81 day average, where the
> >> 81 days the center day, 40 days in the past, and 40 days in the future.
> >> The problem with this definition is that this parameter is never
> >> available for any day less than 40 days in the past. For example, since
> >> MSIS uses FBAR as an input, this means that MSIS also cannot be run for
> >> any day less than 40 days in the past.
> >>
> >> Phil has suggested that for any day less than 40 days in the past, we
> >> calculate FBAR as an average over the most recent 81 days. From the
> >> Madrigal point-of-view, this means that every time we reload geophysical
> >> data, the FBAR values for the latest 40 days might change slightly. At
> >> present, FBAR is not loaded into Madrigal for days less than 40 days ago.
> >>
> >> We would document this FBAR definition on the Madrigal help pages. Any
> >> thoughts?
> >>
> >> Bill Rideout
> >> _______________________________________________
> >> OpenMadrigal-developers mailing list
> >> OpenMadrigal-developers at openmadrigal.org
> >> http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers
> >>
> >>
> >>
> >
> > _______________________________________________
> > OpenMadrigal-developers mailing list
> > OpenMadrigal-developers at openmadrigal.org
> > http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers
> >
> >
> >
>
>
> --
>
> _____________________________________________________________
> Shunrong Zhang (shunrong at haystack.mit.edu)
> http://www.haystack.mit.edu/~shunrong/
> MIT Haystack Observatory, Route 40, Westford, MA 01886, USA
> Phone: 781-981-5725 FAX: 781-981-5766
>
> _______________________________________________
> OpenMadrigal-developers mailing list
> OpenMadrigal-developers at openmadrigal.org
> http://www.openmadrigal.org/mailman/listinfo/openmadrigal-developers
>
> !DSPAM:45391edb37962061126357!
More information about the OpenMadrigal-developers
mailing list