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:Product: NWRA 24h Effective SSN Analysis :Issued: 2023-06-03 09:41 UT # Prepared by NorthWest Research Associates, Inc. # Uses foF2 data from NOAA/NCEI. # #Hemisphere YYYYMMDD HH SSNe RMS RMS% # Status #---------- -------- -- ------ ------ ------ --- ------ Global 20230603 09 99.09 1.29 28.51 599 GRN Northern 20230603 09 108.71 0.81 11.18 322 GRN Southern 20230603 09 89.19 1.55 36.47 255 GRN #---------- -------- -- ------ ------ ------ --- ------ # Status: Green # Hours to last foF2 observation: 0 # Listings of past 5 hours: Global SSNe YYYYMMDD HH SSNe RMS RMS% # -------- -- ------ ------ ------ --- 20230603 05 98.90 1.30 27.62 595 20230603 06 98.56 1.30 27.66 595 20230603 07 98.38 1.30 28.12 596 20230603 08 98.81 1.29 28.05 596 20230603 09 99.09 1.29 28.51 599 -------- -- ------ ------ ------ --- Northern Hemisphere SSNe YYYYMMDD HH SSNe RMS RMS% # -------- -- ------ ------ ------ --- 20230603 05 105.51 0.81 11.14 319 20230603 06 105.42 0.81 11.14 320 20230603 07 106.18 0.82 11.17 320 20230603 08 107.58 0.81 11.08 320 20230603 09 108.71 0.81 11.18 322 -------- -- ------ ------ ------ --- Southern Hemisphere SSNe YYYYMMDD HH SSNe RMS RMS% # -------- -- ------ ------ ------ --- 20230603 05 91.22 1.62 36.54 255 20230603 06 90.62 1.61 36.44 254 20230603 07 89.82 1.59 36.61 255 20230603 08 89.52 1.57 36.10 255 20230603 09 89.19 1.55 36.47 255 -------- -- ------ ------ ------ ---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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