Real time Solar Radio Flux from data published by the
Space Weather Prediction Center (SWPC)

The Solar Radio Flux is given by the yellow curve on the plot. This curve is obtained using Lagrange's interpolation algorithm between values published by the SWPC (more details below). Below 245 MHz, curve accuracy decreases when frequency decreases. However, accuracy remains sufficient for amateur purpose.

The so-called "Quiet Sun, 1965" curve shows the Quiet Sun Radio Flux obtained by averaging minimum quiet sun data for 1965. This curve only gives an order of magnitude of what can be expected during lowest quiet sun activity, and can be used as a reference for evaluating at glance real time solar flux changes.

Sometimes, instead of showing its usual "ski jumping ramp" shape, the curve may exhibit severe distortions, especially on its lower frequency side. This is mainly due to solar bursts occuring on the VHF part of the observed RF spectrum.

Space Weather Prediction Center (SWPC)
Solar Radio Flux Data Lists

The Solar Radio Flux lists contain noon flux values from Penticton, Canada and the U.S. Air Force Radio Solar Telescope Network (RSTN) sites. The RSTN sites are Learmonth (Australia), San Vito (Italy), Sagamore Hill (Mass.) and Palehua (Hawai). RSTN sites measure the solar radio flux within one hour of central meridian passage (CMP), that is near their local noon. Penticton records values 3 times a day with the 2000 UTC value being closest to central meridian passage.

     Location	     Latitude	   Longitude	  Locator	  Reporting time	
 Learmonth	 22°13' 9" S	 114° 6' 11" E	  OG77BS	       0500 UTC	
 San Vito	 40° 40' N	 17° 43' E	  JN80UQ	       1200 UTC	
 Sagamore Hill	 42° 37' 56" N	 70° 49' 12" W	  FN42OP	       1700 UTC	
 Penticton	 49.30 N	 119.35 W	  DN09HA	       2000 UTC	
 Palehua	 21° 23' 12" N	 158° 6' 18" W	  BL01WJ	       2300 UTC	

All values from the USAF stations are adjusted to 1 AU. (Note: in this specific software, these values are further re-adjusted for true Earth to Sun distance of date).

The Penticton values are NOT adjusted to 1 AU. Adjusted and unadjusted values from Penticton are available at the National Geophysical Data Center about one month later.

Solar Radio Spectrum

Level of Origin	Freq (MHz)	Wavelength	
Lower Chromosphere	15400	1.9 cm	
	8800	3.4 cm	
Middle Chromosphere	4995	6.0 cm	
	2695	11.1 cm	
Upper Chromosphere	1415	21.2 cm	
	610	49.2 cm	
	410	73.2 cm	
Lower Corona	245	1.2 m	
Upper Corona	75 to 25	4.0 m to 12.0 m	

The output is a table with one row for each frequency and one column for each site. The value is the flux, missing values are shown as -1. Values range from 1 to 999.

Radio Flux lists updated hourly at 30 minutes past the hour. Radio Bursts list updates twice an hour at 10 and 40 minutes past the hour.

Sample of published data, for two-day radio flux values:

:Product: Solar Radio Data             2day_rad.txt
:Issued: 1142 UTC 06 Oct 2009
#
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
# Please send comments and suggestions to SWPC.Webmaster@noaa.gov
#  Units: 10^-22 W/m^2/Hz
#  Missing Data:  -1
#
#    Daily local noon solar radio flux values - Updated once an hour
#
  Freq  Learmonth  San Vito  Sag Hill  Penticton  Penticton  Palehua  Penticton
   MHZ   0500 UTC  1200 UTC  1700 UTC   1700 UTC   2000 UTC  2300 UTC  2300 UTC

2009 Oct 5
  245       12        -1        13         -1         -1        11        -1
  410       28        28        27         -1         -1        28        -1
  610       32        -1        32         -1         -1        36        -1
 1415       54        54        56         -1         -1        57        -1
 2695       73        76        74         -1         -1        74        -1
 2800       -1        -1        -1         -1         70        -1        69
 4995      118       108       118         -1         -1       118        -1
 8800      213       215       222         -1         -1       215        -1
15400      529       487       525         -1         -1       518        -1

2009 Oct 6
  245       12        -1        -1         -1         -1        -1        -1
  410       27        27        -1         -1         -1        -1        -1
  610       32        -1        -1         -1         -1        -1        -1
 1415       55        54        -1         -1         -1        -1        -1
 2695       72        74        -1         -1         -1        -1        -1
 2800       -1        -1        -1         -1         -1        -1        -1
 4995      118       108        -1         -1         -1        -1        -1
 8800      210       209        -1         -1         -1        -1        -1
15400      516       484        -1         -1         -1        -1        -1

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