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Re: [dxatlas] 90-day SSN data for HamCAP

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  • bill_w4zv
    ... wondering why ... I agree. Seems like measured solar flux, which supposedly shows the actual effect of sunspots on the ionosphere, would be better. After
    Message 1 of 17 , Apr 10, 2005
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      --- In dxatlas_group@yahoogroups.com, Pete Smith <n4zr@c...> wrote:

      >
      > So, where does this leave us? Where it left me, frankly, is
      wondering why
      > we use sunspot numbers at all, rather than solar flux and A/K indices,

      I agree. Seems like measured solar flux, which supposedly shows the
      actual effect of sunspots on the ionosphere, would be better. After
      all, when there is a large CME, we often can see little effect on the
      ionosphere depending on how it's directed toward Earth, which way Bz
      points, etc. Of course if VOACAP was originally based on SSN's, then
      maybe they should be the input. Hopefully Greg Hand will respond, and
      please post anything of interest here since I am not on that list. No
      model is any better than its input..."Garbage In Garbage Out" as
      someone said.

      73, Bill
    • bill_w4zv
      I wrote: The current 90 day average (1 Jan 05 - 31 Mar 05) is 28.4 using this data: ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/RIDAILY.PLT VE3NEA
      Message 2 of 17 , Apr 10, 2005
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        I wrote: The current 90 day average (1 Jan 05 - 31 Mar 05) is
        28.4 using this data:
        ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/RIDAILY.PLT

        VE3NEA wrote: These are the RI indices, not daily SSN values.

        Alex, the NOAA site below calls these "Provisional International
        Sunspot Numbers, so what do you mean they are not daily SSN numbers?
        See especially their comments preceded by ***** below:
        ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/sunspot.predict

        >The provisional daily Zurich relative sunspot numbers, Rz, were based
        upon
        observations made at Zurich and its two branch stations in Arosa and
        Locarno
        and communicated by M. Waldmeier of the Swiss Federal Observatory.
        Beginning
        January 1, 1981, the Zurich relative sunspot number program is
        replaced by
        the "Sunspot Index Data Center" (c/o Dr. P. Cugnon, 3 av. Circulaire,
        B-1180
        Bruxelles, Belgium).


        ***** The determination of the provisional International Sunspot
        Numbers Ri results from a statistical treatment of the data
        originating from more than twenty-five observing stations. These
        stations constitute an international network, with the Locarno
        (Switzerland) station as the reference station, to guarantee
        continuity with the past Zurich series of Rz.*****

        >The definitive International Sunspot Numbers Ri are evaluated by a
        similar method based on a network of observing stations selected for
        their
        high number of observations, their continuity during the whole year
        and an
        existing series of observations during the last years. Also taken into
        account is the stability of the K monthly factors with reference to the
        Locarno station.

        *****These relative sunspot numbers are now designated Ri
        (International) instead of Rz (Zurich).*****

        It seems to me Ri is exactly what should be used, but am really
        waiting to see what Greg Hand, etc. of VOACAP have to say.

        73, Bill
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