------------------------------------------------------------------- 25 CYCLE OF SOLAR ACTIVITY, THE BRANCH OF RISE: THE PHASE OF MINIMUM THE RELATIVE MONTHLY MEAN SUNSPOT NUMBER ON SEPTEMBER 2021 HAS MADE Wsep. = 30.9 51.5(in new system) THAT GIVES FOR 15 MONTH (2021, MARCH) OF DEVELOPMENT CURRENT 25 SOLAR CYCLE THE SMOOTHED MONTHLY MEAN SUNSPOT NUMBER W*mar. = 13.1 21.8 - in new system W*feb. = 11.5 19.1 - in new system On July 1, 2015 Centre in Brussels moved to a new system of calcu- lation the relative number of sunspots and practically all of the values were replaced throughout the numbered series of Wolf numbers (see link). While there is addictive, I recalculated (0.6) to the old system, but only W*, and present below the new values for the minimum and maximum of 25 cycles SA. THE BEGINNING OF 25 SOLAR CYCLE - I 2020 with W*=1.3; (1.8n) MAXIMUM OF THE CURRENT 25 CYCLE - VI 2024 - Wmax =90-100; (150n) THE END OF 25 SOLAR CYCLE (THE POINT OF MINIMUM) - I - VI 2031; Provisional daily International Sunspot Numbers for SEPTEMBER 2021 (69 observatories): 1.. 38 6.. 83 11.. 74 16.. 0m 21.. 65 26.. 50 2.. 33 7.. 84 12.. 50 17.. 0m 22.. 81 27.. 49 3.. 25 8.. 98 13.. 34 18.. 0m 23.. 69 28.. 56 4.. 70 9..102M 14.. 23 19.. 13 24.. 61 29.. 70 5.. 75 10.. 97 15.. 10 20.. 44 25.. 46 30.. 45 [The daily value W in old system close to true (in a minimum phase) can be received, multiplying by k = 0.6]. THE MONTHLY MEAN OF OBSERVED RADIO FLUX OF THE 10 cm (2800 MHz) ON SEPTEMBER 2021, AND SMOOTHES ON 2021, MARCH F10.7sep. = 87.0 F*10.7mar.= 79.0 THE MONTHLY MEAN OF GEOMAGNETIC Ap-index ON SEPTEMBER 2021, AND SMOOTHES ON 2021, MARCH Ap sep.= 6.6 Ap*mar. = xxx --------------------------------------------------------------------- Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 27.09 - 03.10.2021, Forecast on 04 - 11.10.2021 Carrington Rotations 2249 (24,59.09. 2021) Earth out of ecliptic (1.3 - 0.6) deg. (S30 - N30 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY WAS ON MIDDLE AND LOW LE- VELS. THE ESTIMATED MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD IS W=37+8/-14 (Wn=62+13/-24). THERE ARE 5 SMALL QUITE SUNSPOT GROUPS ON VISIBLE SOLAR DISK, 3 ON N-HEMISPHERES) HAS BEEN OB- SERVED. NEXT WEEK SUNSPOT ACTIVITY WILL BE ON MIDDLE AND LOW LEVELS. WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE IN- TERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=040+30/-20. FLARE ACTIVITY WAS AT MIDDLE AND LOW LEVELS. 11 FLARES OF X- RAY CLASS "C", 66 - CLASS "B", 3 SOLAR FILAMENT EJECTIONS AND 12 CORONAL MASS EJECTIONS (26-29.09) HAVE BEEN OBSERVED. ------------------------------------------------------------------- FLARES >M1 X-RAY CLASSES to tm te local. Class E(1-8A) AR RII/IV CME X-ray/Ïp J/m-2 DSF to te localization l deg. Fl AR CME/to 02.10 <1930 SW L~351 >10 CME/1930 03.10 >0028 >1331 N23W01L246 11 03.10 >0028 >1331 S23W09L238 7 -------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT VERY LOW AND LOW LEVELS. ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED: --------------------------------------------------------------------- sign N end E end S end W end Sch EE R G Spacecraft CH* - N20L052 N05L057 S05L056 N10L051 1.1% 27.08 R1 SDO,SOHO... * - low geoeffectivity, the substorms with duration <6 h. only. Sch - CH area in % solar hemisphere near the central meridian on https://www.solarmonitor.org/; n/d - no data; R - solar rotations; EE-date of possible geomagnetic disturbance in the Earth's environment. G(0-5)-geoeffectivity in last solar rotation on the middle latitudes. A-active geomagnetic condition. ---------------------------------------------------------------------- 27.09/2035 - 03.10/1630 UT THE EARTH IS IN THE "+" SECTOR OF THE INTER PLANETARY MAGNETIC FIELD. FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE EX- PECT 5.10. ----------------------------------------------------------------------- SEPTEMBER 27 28 29 30 01 02 03 ïëôñâòø Wus 030 057 074 046 028 025 038 F10.7 085 089 102 095 091 087 086 èbcg á8.7 ÷1.5 ÷3.0 ÷2.2 B1.5 ÷1.3 ÷1.2 GOES Sp 090 080 540 400 460 380 440 msh N 2 IMF -/+ + + + + + +/- DSCOVR Å>2 3.4E+6 4.5E+6 1.0E+7 8.6E+6 1.5å+6 1.6E+6 1.3E+6 GOES Ie>2 696 290 449 616 148 140 142 pfu Ap 7 10 5 9 16 8 6 nô Dst nô KIOTO Amsc 7 12 5 9 16 10 7 IZMIRAN ------------------------------------------------------------------------ Å>2 - Daily Electron Fluency e/(cm2-ster-day) with E>2 MeV. Ie>2 - the maximum intensity of electron flux in geostationary or- bits in days according to GOES-15 in (electrons/cm2.s.sr) for events > 1000 pfu. THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT NOT OBSERVED. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS NOT EXPECTED - NO GEOEFFECTIVE CORONAL HOLES. THE GEOMAGNETIC CONDITION WAS QUIET AND UNSETTLED ALL DAYS. THE NEXT WEEK IS MOST PROBABLE A QUIET AND UNSETTLED GEOMAGNETIC CONDITION ALL DAYS. HIGHLIGHT AND FORECAST COMPOSED FROM DATA: NOAA SWPC, BOULDER, USA http://www.swpc.noaa.gov, THE SOLAR INFLUENCES DATA ANALYSIS CENTRE, SIDC, BRUSSELS, BELGIUM http://sidc.oma.be/index.php3, THE IZMIRAN, MOSCOW, TROITSK, RUSSIA http://www.izmiran.ru V. Ishkov