Solar Influences Data Center (SIDC) / RWC Belgium Royal Observatory of Belgium E-mail: Pierre.Cugnon@oma.be http://sidc.oma.be SIDC WEEKLY BULLETIN -------------------- WEEK 113 from 2003 Feb 24 SOLAR ACTIVITY -------------- Solar activity was very low during the week, in particular the beginning of the week. For the largest fraction of the week, there was only one AR worth mentionning: NOAA 0290 with a beta-gamma configuration. This active region did not produce anything bigger than a C-flare. In fact, not a single M-flare was recorded throughout the periode. On Wednesday morning (Feb 26, 02h00 UT), a beautiful prominence eruption was observed by EIT from the SW limb. No corresponding LASCO images were available because of SOHO manouvers. In the second half of the week a few big active regions came rotating into the view at the solar East limb. This raised the background GOES X-ray flux from an A8 (beginning of the week) to a B5 level (end of the week), and the 10 cm flux from 102 to 147. GEOMAGNETIC ACTIVITY -------------------- The solar wind in situ observations by the ACE spacecraft indicated the passage of a coronal hole influence cone on Wednesday February 26 (noon) till Friday February 28 (early morning). This coronal hole could indeed be located in Southern solar hemisphere. As a consequence, active geomagnetic conditions (Kp=4) were recorded over roughly the same time frame. --------------------------------------------------------------------------- DAILY INDICES DATE RC 10CM Ak BKG M X 2003 Feb 24 /// 102 007 A8.0 0 0 2003 Feb 25 /// 102 005 A9.4 0 0 2003 Feb 26 /// 109 012 B2.2 0 0 2003 Feb 27 /// 118 032 B4.1 0 0 2003 Feb 28 /// 125 019 B4.5 0 0 2003 Mar 01 /// 138 019 B5.1 0 0 2003 Mar 02 /// 147 015 B5.3 0 0 # RC : Sunspot index from Catania Observatory (Italy) # 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 10CM TYPE Cat NOAA NOTE