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194Re: [dxatlas] 90-day SSN data for HamCAP

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  • bill_w4zv
    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:

      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:

      >The provisional daily Zurich relative sunspot numbers, Rz, were based
      observations made at Zurich and its two branch stations in Arosa and
      and communicated by M. Waldmeier of the Swiss Federal Observatory.
      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,
      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
      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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