Space Weather: Real-Time 24hr Effective Sunspot Number

SSNe24 7-day plot

Note: This plot is updated hourly. See below for a data-use summary.

Track the status of the solar-cycle for the past 12 months or for Cycle 23.

If you are looking for the observed sunspot number derived from optical observations of the sun, you've been miss-routed.
This link provides a comparison of the effective SSN shown on this page to the observed solar sunspot number.

The parameter shown in the upper plot is the effective sunspot number (SSNe) calculated using real-time foF2 observations collected during the 06- or 24-hour period ending at the date/time the SSNe is plotted for. The data plotted in the lower plot are the RMS percent difference between the foF2 observations used in the SSNe calculation and the model foF2 values generated using the SSNe in the URSI-88 foF2 model. The heavy and light curves for both SSNe and the RMS foF2 differences correspond to values calculated using the past 24 hours of foF2 data (heavy lines) and values calculated from the past 06 hours of foF2 data (light lines). Note the quasi-diurnal variation in the 06hr SSNe values, which is due primarily to unequal longitude spacing of the foF2 stations from which the SSNe are being calculated.

The heavy line along the top of the plot is a rough indicator of the number of foF2 values used in the 24hr near-real-time calculation. A wide line indicates that at least 350 values were used, and narrower line indicates less than 350 but more than 200, and no line indicates fewer than 200. The number of foF2 values used and the RMS foF2 difference can be used as an indicator of the usefulness and validity of a particular SSNe value.

The following table summarizes the observations used in calculating the most recent SSNe value. The X entry for a particular station/time indicates there was an foF2 value available and it was used in the SSNe calculation. A - entry indicates that an foF2 value was available, but it was excluded from the SSNe calculation (it was identified as an outlier point). The bar (|) symbol along the time axis of the table indicates the latest-data time (ie., data to the right of this column are from the previous day).

Date: 20081119                          000000000011111111112222 
GMLAT  Station              Used  Rej   012345678901234567890123 
-----  -------------------  ---- ----  +-----------------------|+
 49.7  Boulder                20   00  | XXXX XXXXXXXXXXXXXX XX||
 49.4  Fairford               24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 49.1  Chilton                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 49.0  Wallops Island         00   00  |                       ||
 48.3  Warsaw                 00   00  |                       ||
 46.8  Dourbes                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 46.3  Pruhonice              09   00  |XXXXXXXXX              ||
 43.5  Manzhouli              00   00  |                       ||
 42.5  Dyess AFB              23   00  |XXXXXXXXXXXXXXX XXXXXXXX|
 42.5  Bermuda                00   00  |                       ||
 42.1  Eglin AFB              00   00  |                       ||
 41.6  Khabasrovsk            09   00  |XXXXXXXXX              ||
 40.6  Point Arguello         23   00  |XXXXXXXXXXXXXXXXX XXXXXX|
 38.7  Wakkanai               00   00  |                       ||
 36.8  Rome                   13   00  |XXXXXXXXXX XXX         ||
 36.3  Roquetes               18   00  |XXXXXXXXXX XXXXXXXX    ||
 35.4  San Vito               24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 34.1  Beijing                00   00  |                       ||
 32.6  Athens                 15   00  |X X XXXX XXXX XXX XX   ||
 32.4  Ashkhabad              06   00  |       XXXXXX          ||
 32.0  El Arenosillo          00   00  |                       ||
 30.5  Osan AFB               00   00  |                       ||
 30.5  Anyang                 02   00  |  X X                  ||
 30.3  Ramey                  00   00  |                       ||
 28.7  Kokubunji              00   00  |                       ||
 22.6  Chongqing              00   00  |                       ||
 18.9  Okinawa                00   00  |                       ||
 16.0  Guangzhou              00   00  |                       ||
  4.0  Kwajalein              17   01  | X- XXXXXXXXX X XX X XXX|
  0.9  Jicamarca              16   07  |----XXXXXX XXXXXXXXXX---|
-11.8  Vanimo                 05   02  |XX--XXX                ||
-17.0  Ascension Island       17   00  | XXXX   XXXXXXXXXXXXX  ||
-18.6  Port Moresby           00   00  |                       ||
-22.3  Darwin                 20   00  |XXXXXXXX XXXXXXX  XXX XX|
-23.1  Cocos Island           00   00  |                       ||
-25.3  Nuie                   00   00  |                       ||
-28.9  Townsville             06   00  |X X             X   XX X|
-32.8  Madimbo                10   00  |      XXXXXXXXXX       ||
-32.9  Learmonth              24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
-36.5  Norfolk Island         23   00  |X XXXXXXXXXXXXXXXXXXXXXX|
-36.9  Brisbane               21   00  |XXXXXXXXXXXXXXXXXXX   XX|
-38.3  Port Stanley           16   00  |X XXXXX  X X XXXXXXXX  ||
-38.6  Louisvale              10   00  |             XXXXXXXXXX||
-41.9  Grahamstown            11   00  |             XXXXXXXXXXX|
-42.2  Hermanos               10   00  |              XXXXXXXXXX|
-44.7  Camden                 11   00  |  X X  X XXXX   XX  XX ||
-45.1  Mundaring              00   00  |                       ||
-46.0  Canberra               09   00  |  X   X XX   X    XX XX||
-------------------  -----  ---- ----  +-----------------------|+
  # Expected / # Received / Percent: 1128 / 470 /  41.7

If you would like to get a feel for how effective these effective-SSN indices are, foF2 plots comparing the observations with model foF2 values calculated using the NWRA and 55SWS SSNe values are available. There is a one-day delay between the latest SSNe values available and these plots to permit more data to arrive at the NOAA SWPC for comparison.

Daily foF2 Comparison Plots

For more information on NWRA Space Weather activities, send e-mail to: Jim Secan (NWRA)

The foF2 data used in these calculations were obtained from the NOAA SWPC. These data are being made avaiable from SWPC on a test basis, so there will be occassional periods of data loss as their system is tested.

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