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:Product: NWRA 24h Effective SSN Analysis :Issued: 2023-02-05 06:41 UT # Prepared by NorthWest Research Associates, Inc. # Uses foF2 data from NOAA/NCEI. # #Hemisphere YYYYMMDD HH SSNe RMS RMS% # Status #---------- -------- -- ------ ------ ------ --- ------ Global 20230205 06 99.40 1.33 19.39 601 GRN Northern 20230205 06 91.24 1.06 19.11 339 GRN Southern 20230205 06 112.19 1.55 17.45 239 GRN #---------- -------- -- ------ ------ ------ --- ------ # Status: Green # Hours to last foF2 observation: 0 # Listings of past 5 hours: Global SSNe YYYYMMDD HH SSNe RMS RMS% # -------- -- ------ ------ ------ --- 20230205 02 104.31 1.43 20.33 599 20230205 03 103.43 1.42 20.15 602 20230205 04 102.21 1.38 19.77 602 20230205 05 100.81 1.36 19.60 600 20230205 06 99.40 1.33 19.39 601 -------- -- ------ ------ ------ --- Northern Hemisphere SSNe YYYYMMDD HH SSNe RMS RMS% # -------- -- ------ ------ ------ --- 20230205 02 97.37 1.26 20.49 339 20230205 03 96.42 1.24 20.34 339 20230205 04 94.55 1.17 19.79 339 20230205 05 92.87 1.12 19.47 338 20230205 06 91.24 1.06 19.11 339 -------- -- ------ ------ ------ --- Southern Hemisphere SSNe YYYYMMDD HH SSNe RMS RMS% # -------- -- ------ ------ ------ --- 20230205 02 115.74 1.61 18.69 237 20230205 03 114.96 1.59 18.31 240 20230205 04 114.55 1.57 17.86 240 20230205 05 113.44 1.56 17.66 239 20230205 06 112.19 1.55 17.45 239 -------- -- ------ ------ ------ ---Updated hourly at 40 minutes past the hour The SSNe index presented on the NWRA website is calculated using the URSI coefficient-based model for foF2 commonly referred to as the URSI-88 model (Rush et al., 1989). The foF2 data used are provided from a global network of ionospheric sounders currently collected at the National Centers for Environmental Information (NCEI). An SSNe index is generated once per hour for four different set of observed foF2: (1) all observations equatorward of 50 degrees geomagnetic latitude over the past 24 hours (SSNe24), (2) all observations equatorward of 50 degrees geomagnetic latitude over the past 6 hours (SSNe06), (3) all observations between +15 and +50 degrees geomagnetic latitude (NH SSNe24) over the past 24 hours, and (4) all observations between -15 and -55 degrees geomagnetic latitude (SH SSNe24) over the past 24 hours. A more detailed description of the algorithms used and a review of the efficacy of using SSNe can be found in Secan and Wilkinson (1997). NOTE: The international solar community has recalibrated and rescaled the sunspot number and refer to the new scaling as the V2.0 sunspot series. The foF2 model the SSNe estimate is calculated from was based on the V1.0 sunspot number series. Thus all SSNe values are inherently tied to the V1.0 scaling. If the software you plan to use SSNe with explicitly states that the input sunspot number must be consistent with the V2.0 sunspot series you should divide the SSNe by 0.7 to obtain the corresponding V2.0 value. Rush, C., M. Fox, D. Bilitza, K. Davies, L. McNamara, F. Stewart, and M. PoKempner, Ionospheric Mapping: An Update of foF2 Coefficients, Telecommun. J., 56(179), 1989. Secan, J.A. and P.J. Wilkinson, Statistical studies of an effective sunspot number, Radio Science, 32, 1717-1724, 1997. |
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