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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: 20140723                          000000000011111111112222 
GMLAT  Station              Used  Rej   012345678901234567890123 
-----  -------------------  ---- ----  +---------|--------------+
 49.7  Boulder                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 49.4  Fairford               00   00  |         |              |
 49.1  Chilton                00   00  |         |              |
 49.0  Wallops Island         24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 48.3  Warsaw                 18   00  |XXXXXXXXX| X XX X XXXXX |
 46.8  Dourbes                00   00  |         |              |
 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              00   00  |         |              |
 41.6  Khabasrovsk            00   00  |         |              |
 40.6  Point Arguello         00   00  |         |              |
 38.7  Wakkanai               09   00  |XX     XX|X  X      XX X|
 36.8  Rome                   18   00  |XXXXXXX X|X XX X XX XXXX|
 36.3  Roquetes               00   00  |         |              |
 35.4  San Vito               00   00  |         |              |
 34.1  Gibilmanna             24   00  |XXXXXXXXXXXXXXXXXXXXXXXX|
 34.1  Beijing                00   00  |         |              |
 33.2  I-Cheon                23   00  |XXXXXXXXXXXXXXX XXXXXXXX|
 32.6  Athens                 21   00  |XXXXXX XXX  XXXXXXXXXXXX|
 32.4  Ashkhabad              00   00  |         |              |
 32.0  El Arenosillo          18   00  |XXXXXXX XX    XXXX XXXXX|
 30.5  Osan AFB               00   00  |         |              |
 30.5  Anyang                 00   00  |         |              |
 30.3  Ramey                  23   01  |XXXXXXXXXXXXXXX-XXXXXXXX|
 29.9  San Juan               00   00  |         |              |
 29.4  Jeju                   21   00  |XXXXXXXXXXXXX XXXXX X XX|
 28.7  Kokubunji              17   00  |X   XXXXXX  XXX XXXXXX X|
 24.0  Yamagawa               17   00  |XXX X XXXXXX X   X XXXXX|
 22.6  Chongqing              00   00  |         |              |
 18.9  Okinawa                18   00  |XXX XXXXXXXX  X   XXXXXX|
 16.0  Guangzhou              00   00  |         |              |
  4.0  Kwajalein              00   00  |         |              |
  0.9  Jicamarca              20   00  |XXXXXXXXXX  XXXX  XXXXXX|
-11.8  Vanimo                 00   00  |         |              |
-17.0  Ascension Island       00   00  |         |              |
-18.6  Port Moresby           00   00  |         |              |
-22.3  Darwin                 20   00  |XXXXX XXXX XXXXXXXX  XXX|
-23.1  Cocos Island           16   01  |XXXXXXXXXXXXX XXX    -  |
-25.3  Nuie                   22   00  |XXXXX XXX|XXXXXXXXXXXXXX|
-28.9  Townsville             18   00  |XXXX XXXXX XX XX XX XX X|
-32.8  Madimbo                00   00  |         |              |
-32.9  Learmonth              11   00  |XXXX XX XXXX          X |
-36.5  Norfolk Island         16   00  |XX XXXXXXX X   XXXX  XX |
-36.9  Brisbane               19   00  |XXXXXXXXXXXXXX     XXXXX|
-38.3  Port Stanley           00   00  |         |              |
-38.6  Louisvale              16   07  |X----XXXX|XXXXXXXXXXX---|
-41.9  Grahamstown            15   09  |-----XXXXXXXXXXXXXXX----|
-42.2  Hermanos               15   09  |-----XXXXXXXXXXXXXXX----|
-44.7  Camden                 19   00  |X XXXXXX XXXX X XX XXXXX|
-45.1  Mundaring              00   00  |         |              |
-45.6  Perth                  17   03  |XX XXXX XXXXX  -XXXX--XX|
-46.0  Canberra               21   01  |XXXXXXXXX|XXXXXXX -XXXXX|
-------------------  -----  ---- ----  +---------|--------------+
  # Expected / # Received / Percent: 1248 / 575 /  46.1
 

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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