Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 14 - 20.12.2020, Forecast on 21 - 28.12.2020, Carrington Rotations 2238, 2239(28,61.11; 25,94.12.2020 Earth out of ecliptic (0.8 - 0.2) deg. (S30 - N30 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON LOW AND VERY LOW LEVEL. THE VISIBLE SOLAR DISC WAS SPOTLESS 18-19.12. (208 DAYS AT 2020) ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUN- SPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD W=7+8/ -7 (Wn= 11+14/-11). ON THE VISIBLE DISK OF THE SUN THREE SMALL SUNSPOT GROUPS HAVE BEEN OBSERVED. NEXT WEEK SUNSPOT ACTIVITY WILL BE AT VERY LOW AND LOW LEVELS. LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=010+15/-10. FLARE ACTIVITY WAS AT LOW AND VERY LOW LEVELS. 1 SOLAR FLARE OF LOW X-RAY CLASS "C", 27 -CLASS "B", ONE SOLAR FILAMENT EJECTA AND 10 CORONAL MASS EJECTIONS (13-15, 17, 19.12) 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 15.12 1925 S36W26l108 5 CME? -------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT VERY LOW AND LOW LEVEL. ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED: --------------------------------------------------------------------- sign N end E end S end W end Sch EE R G Sp/craft CH + P N25E05l076 N20W02L069 N30W20L051 <13% 23.12 2 - SDO... * - 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. ---------------------------------------------------------------------- FROM 14.12/19 UT, THE EARTH IS IN THE "+" SECTOR OF THE INTERPLANETA- RY MAGNETIC FIELD. THE FOLLOWING THE NEXT SECTOR BOUNDARY "+/-" IT CAN BE EXPECT 27.12. ---------------------------------------------------------------------- DECEMBER 14 15 16 17 18 19 20 DECEMBER Wus 025 025 012 012 000 000 011 F10.7 083 083 082 082 082 082 084 èbcg á6.8 á6.6 á4.9 á4.0 á3.3 á5.7 á6.0 GOES Sp 020 030 030 010 000 000 120 msh N 1 IMF -/+ + + + + + + DSCOVR Å>2 5.7E+6 5.0å+6 4.4E+6 2.9E+6 2.8E+6 1.5E+6 1.3å+6 GOES Ie>2 464 289 245 239 251 144 217 pfu Ap 3 3 3 2 2 5 4 nô Dst nô KIOTO Amsc 3 3 2 2 2 4 4 nô 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. ALL DAYS THERE IS QUITE GEOMAGNETIC CONDITION HAVE BEEN OBSERVED. IN THE NEXT WEEK, 23 - 24.12, THE GROWTH OF DISTURBANCES OF THE GEOMAGNETIC FIELD IS POSSIBLE DUE TO THE EARTH'S PASSAGE OF A HIGH-SPEED STREAM FROM THE CORONAL HOLE "+" POLARITY OF THE NOR- THERN HEMISPHERE. THE PROBABILITY OF A MINOR MAGNETIC STORM IS NOT MORE THAN 40%. ON THE OTHER DAYS, THE MOST PROBABLE IS A QUI- TE AND UNSETTLED GEOMAGNETIC CONDITION. 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