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SSNe24 7-day plot

Note: This plot is updated hourly.

Track the status of the solar-cycle for the past 12 months or for Cycles 23-25.

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.


These plots provide a look at the global behavior of the ionospheric F2 layer over the past week as measured by the NWRA effective sunspot number (SSNe) calculated from current observations. The upper panel shows the SSNe variation, the third panel provides a goodness-of-fit metric (described below), and the lower panel gives the total number of foF2 observations in each SSNe calculation. In all three panels the two black curves use data from observatories between -50 and +50 degrees geomagnetic latitude (heavy curve uses data collected from the previous 24 hours; light curve the previous 6 hours). The heavy green and red curves use data from observatories between -50 and -15, and +15 and +50 degrees geomagnetic latitude, respectively, collected during the previous 24 hours. (Note that the quasi- diurnal variation in the 6 hour SSNe values is primarily due to unequal longitude spacing of the foF2 stations from which the SSNe are being calculated.)

The second panel shows the provisional (quicklook) Kp index from GFZ Potsdam. This is provided to assess the impact of geomagnetic activity on SSNe.

Also shown on the upper panel is the long-term predicted smoothed sunspot number as provided by the NOAA Space Weather Prediction Center. The heavy dash line is the expected value from the prediction, and the two light dashed lines are the upper- and lower-bounds on the expected value.

The goodness-of-fit metric shown in the middle panel is the RMS percent difference between the foF2 observations used in the SSNe calculations and the model foF2 values generated using the SSNe in the URSI-88 foF2 model. It generally runs around 15%, with the largest departures occurring during major geomagnetic disturbances

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 (i.e., data to the right of this column are from the previous day). The SH and NH tags on the far right of each line indicates which stations were included in the southern- and northern-hemisphere SSNe calculations, respectively.

Date: 20200805                          000000000011111111112222    
GMLAT  Station              Used  Rej   012345678901234567890123    
-----  -------------------  ---- ----  +----------|-------------+   
 49.8  EAREKSON               22   00  |X XXXXXXXXXXXXXXXXXX XXX| NH
 49.7  BOULDER                15   00  |XXXXXXXXXXX       X  XXX| NH
 49.3  FAIRFORD               22   00  |XXXXXXXXXXXX XX XXXXXXXX| NH
 49.2  CHILTON                18   00  |X XX XXXXX|  XX XXXXXXXX| NH
 48.5  WALLOPS_IS             22   00  |XXXXXXXXXXXXXX XX XXXXXX| NH
 47.2  DOURBES                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX| NH
 47.0  PRUHONICE              23   00  |XXXXXXXXXXX XXXXXXXXXXXX| NH
 45.8  MANZHOULI              13   00  |          |XXXXXXXXXXXXX| NH
 43.9  KHABAROVSK             17   00  | XXX XX   |XXXXXXXXXXXX | NH
 42.0  POINT_ARGUELLO         22   00  |XXXXXXXXXXXXXXXXXXX  XXX| NH
 41.5  AUSTIN                 24   00  |XXXXXXXXXXXXXXXXXXXXXXXX| NH
 40.6  WAKKANAI               18   00  |XXX XXXX XXX XX X XX XXX| NH
 38.0  ROME                   11   00  |XXXXXXXX X|           XX| NH
 36.8  SAN_VITO               22   00  |XXXXXXXXXXX X XXXXXXXXXX| NH
 36.4  BEIJING                13   00  |          |XXXXXXXXXXXXX| NH
 35.5  ASHKHABAD              05   00  |    XXX   |XX           | NH
 33.1  I-CHEON                02   00  |       X  |            X| NH
 31.8  NICOSIA                24   00  |XXXXXXXXXXXXXXXXXXXXXXXX| NH
 31.3  KOKUBUNJI              11   01  | XX XXX  -X  XX X    X X| NH
 29.7  JEJU                   02   00  |          X      X      | NH
 27.4  YAMAGAWA               14   00  |X  X  XXXX| XX  XX  XXXX| NH
 26.6  CHONGQING              08   00  |          |XXXX XXX    X| NH
 24.3  LUALUALEI              23   00  |XXXXXXXXX XXXXXXXXXXXXXX| NH
 23.1  OKINAWA                14   00  |XXX  X XXXXX X     XX XX| NH
 20.8  GUANGZHOU              11   00  |          |XXXX XXXX XXX| NH
 17.0  HAINAN                 09   00  |          |XXXXX    XXXX| NH
 13.7  GUAM                   15   00  |XXX XXXXXXX   X     XXXX|   
-12.2  JICAMARCA              15   00  |XXXXX  X  | XXXXX   XXXX|   
-14.3  FORTALEZA              14   02  |    X    XXXXXXXXXXXXX--|   
-20.0  TUCUMAN                21   00  |XXXX XXXXX|XXXXXXXXX XXX| SH
-22.2  ASCENSION              14   00  |       XXXXXXX XXXXXXX  | SH
-23.0  CACHOEIRA_PAULISTA     23   00  |XXXXXXX XXXXXXXXXXXXXXXX| SH
-24.5  DARWIN                 17   00  |XXX XXXXXXXX XXXX     XX| SH
-25.0  COCOS                  14   00  |XXXX XXXXXXXX X        X| SH
-29.8  BAHIA_BLANCA           19   00  |XXXXXX XX XXXXX XXXXXX  | SH
-30.8  TOWNSVILLE             20   00  |XXXXXXXXXXX XXXXX X  XXX| SH
-34.2  LEARMONTH              20   04  |XXXXXXXXXXXXXXXXXX----XX| SH
-37.5  NORFOLK_IS             18   00  |XXX XXX XXXXX  X X XXXXX| SH
-37.6  BRISBANE               17   00  |XX XXXXXXXXXX   X XXX X | SH
-45.0  CAMDEN                 19   00  |XXXXX X XXXX XXXXXXXXX  | SH
-45.0  PERTH                  22   02  |XXXXXXXXXXXXXXX--XXXXXXX| SH
-46.5  CANBERRA               22   00  |XXX XXXXXXXXX XXXXXXXXXX| SH
-------------------  -----  ---- ----  +----------|-------------+   
NH  :   # Expected / # Received / Percent:  768 /  410 /  53.4
ALL :   # Expected / # Received / Percent: 1272 /  708 /  55.7
SH  :   # Expected / # Received / Percent:  384 /  252 /  65.6
 

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 SSNe and the SWS T indexes 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 NCEI for comparison.

Boulder foF2 Plot Daily foF2 Comparison Plots


The foF2 data used in these calculations were obtained from the NOAA NCEI.

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