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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 Cycles 23 and 24.

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 dashed line in the SSNe plot indicates the maximum 24-hour SSNe that has been observed so far during Cycle 24. This might be from any of the SSNe values calculated during the day, so it might not correspond with the daily SSNe values shown elsewhere on this website. The maximum observed SSNe is calculated once daily, just after 0000 UT.

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: 20141101                          000000000011111111112222 
GMLAT  Station              Used  Rej   012345678901234567890123 
-----  -------------------  ---- ----  +--------|---------------+
 49.7  Boulder                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 49.4  Fairford               23   00  |XXXXXX XXXXXXXXXXXXXXXXX|
 49.1  Chilton                00   00  |        |               |
 49.0  Wallops Island         24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 48.3  Warsaw                 13   00  |XXXXX XX| X   X   XX  XX|
 46.8  Dourbes                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 46.3  Pruhonice              24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 43.5  Manzhouli              00   00  |        |               |
 42.5  Dyess AFB              00   00  |        |               |
 42.5  Bermuda                00   00  |        |               |
 42.1  Eglin AFB              20   00  |X  XXX XXXX XXXXXXXXXXXX|
 41.6  Khabasrovsk            00   00  |        |               |
 40.6  Point Arguello         00   00  |        |               |
 38.7  Wakkanai               17   00  |XXX XXXXX XXXX     XXXXX|
 36.8  Rome                   24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 36.3  Roquetes               24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 35.4  San Vito               23   00  |XXXXXXXXXXXXXXXXX XXXXXX|
 34.1  Gibilmanna             24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 34.1  Beijing                00   00  |        |               |
 33.2  I-Cheon                23   00  |XXXX XXXXXXXXXXXXXXXXXXX|
 32.6  Athens                 00   00  |        |               |
 32.4  Ashkhabad              00   00  |        |               |
 32.0  El Arenosillo          18   00  |XXX XXX X   XXXXXXXXXX X|
 30.5  Osan AFB               00   00  |        |               |
 30.5  Anyang                 00   00  |        |               |
 30.3  Ramey                  00   00  |        |               |
 29.9  San Juan               00   00  |        |               |
 29.4  Jeju                   00   00  |        |               |
 28.7  Kokubunji              24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 24.0  Yamagawa               17   00  |XXXXXXXXXX   X  X X XXXX|
 22.6  Chongqing              00   00  |        |               |
 18.9  Okinawa                19   00  |XXXXXXXXXXXXXX    X XXXX|
 16.0  Guangzhou              00   00  |        |               |
  4.0  Kwajalein              00   00  |        |               |
  0.9  Jicamarca              15   00  |        |XXXXXXXXXXXXXXX|
-11.8  Vanimo                 00   00  |        |               |
-17.0  Ascension Island       21   00  |XXXXXX  |XXXXXXXXXXXXXXX|
-18.6  Port Moresby           00   00  |        |               |
-22.3  Darwin                 06   00  |        |XXXXXX         |
-23.1  Cocos Island           22   01  |XXXXXXXX-XXXXX XXXXXXXXX|
-25.3  Nuie                   00   00  |        |               |
-28.9  Townsville             22   00  |XXXXXXXX|XXXXX XXXXXXXXX|
-32.8  Madimbo                00   00  |        |               |
-32.9  Learmonth              08   00  |XXXXXXX |              X|
-36.5  Norfolk Island         22   00  |XXXXXXXXXXXXX XX XXXXXXX|
-36.9  Brisbane               23   00  |XXXXXXXXXXXXXXXXXX XXXXX|
-38.3  Port Stanley           00   00  |        |               |
-38.6  Louisvale              00   00  |        |               |
-41.9  Grahamstown            24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
-42.2  Hermanos               24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
-44.7  Camden                 23   00  |XXXXXXXXXXXX XXXXXXXXXXX|
-45.1  Mundaring              00   00  |        |               |
-45.6  Perth                  23   00  |XXXXXXXXXXXXXXXXXXXXXX X|
-46.0  Canberra               22   00  |XXXXXX XXXXX XXXXXXXXXXX|
-------------------  -----  ---- ----  +--------|---------------+
  # Expected / # Received / Percent: 1248 / 621 /  49.8
 

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.

Chung-Li Plot Daily foF2 Comparison Plots


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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