:Issued: 2010 Mar 23 1002 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 481 from 2010 Mar 15 SOLAR ACTIVITY -------------- Solar activity was low to very low over the full week, with just a few B subflares. The GOES X-ray background flux was mostly at A level. The largest sunspot group was Catania#52 (NOAA11054), which had spawned a halo CME on March 14. It reached its largest development on March 15 (type D, beta/gamma) but then decayed continuously until it disappeared at the West limb on March 20, without producing any further flaring activity. GEOMAGNETIC ACTIVITY -------------------- The geomagnetic field was quiet to unsettled over the entire week, with just a brief active interval on March 17. This weak disturbance was associated with a temporary enhancement of the solar wind speed that peaked at 500km/s early on March 17. This weak solar wind enhancement could be due either to a recurrent fast solar wind stream or to the glacing blow of the slow halo CME released at the Sun on March 14. The solar wind speed then declined with a plateau at 400km/s on March 19-20, causing temporary unsettled geomagnetic levels. On March 21, all parameters finally returned to very quiet levels. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2010 Mar 15 026 015 86 004 A5.2 0 0 2010 Mar 16 040 015 85 006 A3.8 0 0 2010 Mar 17 027 019 87 008 A4.3 0 0 2010 Mar 18 039 019 86 006 A4.8 0 0 2010 Mar 19 030 015 84 006 A3.8 0 0 2010 Mar 20 016 010 84 006 A6.1 0 0 2010 Mar 21 /// 017 85 002 A6.6 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 # #--------------------------------------------------------------------#