:Issued: 2010 Feb 02 1109 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 474 from 2010 Jan 25 SOLAR ACTIVITY -------------- Three sunspot groups were recorded on the solar disk during the week: Catania numbers 37, 38 and 39 (NOAA ARs 1041, 1042 and 1043 respectively). Catania sunspot group 38 was active in the beginning of the week. It produced several B-class flares on January 26-27, the strongest one being the B6.7 flare on January 26. Late on January 27 it disappeared behind the west limb. Catania sunspot group 37 produced several B-class flares on January 27-28, the strongest one being the B4.0 flare on January 28. Catania sunspot group 39 emerged rapidly on January 30 and produced several B-class flares on January 30-31, including the B4.8 flare on January 31. GEOMAGNETIC ACTIVITY -------------------- During the most of the week, the Earth was inside a slow solar wind stream (speed below 400 km/s). The geomagnetic conditions were quiet. On January 30-31 a slightly faster solar wind stream arrived (peak speed around 450 km/s), accompanied by the interplanetary sector boundary crossing early on January 31. The interplanetary magnetic field north-south component in the stream interaction region was fluctuating and not very strong (down to -5 nT only). The geomagnetic conditions remained quiet. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2010 Jan 25 041 025 81 004 A7.1 0 0 2010 Jan 26 /// 015 80 006 A6.4 0 0 2010 Jan 27 /// 008 78 001 A6.3 0 0 2010 Jan 28 017 008 76 006 A6.2 0 0 2010 Jan 29 011 008 73 002 A2.6 0 0 2010 Jan 30 /// 000 75 006 A2.4 0 0 2010 Jan 31 /// 011 75 005 A3.3 0 0 # RC : Sunspot index (Wolf Number) from Catania Observatory (Italy) # EISN : Estimated International Sunspot Number # 10cm : 10.7 cm radioflux (DRAO, Canada) # Ak : Ak Index Wingst (Germany) # BKG : Background GOES X-ray level (NOAA, USA) # M,X : Number of X-ray flares in M and X class, see below (NOAA, USA) --------------------------------------------------------------------------- NOTICEABLE EVENTS DAY BEGIN MAX END LOC XRAY OP TENCM TYPE Cat NOAA NOTE #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # Fax : 32 (0) 2 373 0 224 # # Tel.: 32 (0) 2 373 0 491 # # # # For more information, see http://www.sidc.be. Please do not reply # # directly to this message, but send comments and suggestions to # # 'sidctech@oma.be'. If you are unable to use that address, use # # 'rvdlinden@spd.aas.org' instead. # # To unsubscribe, visit http://sidc.be/registration/unsub.php # #--------------------------------------------------------------------#