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 158 from 2004 Jan 05 SOLAR ACTIVITY: --------------- Solar activity was at M-level for the first half and at C and B level for the second half of last week. The dominant sunspot group was Catania 33 (NOAA 0537) which appeared at the west limb on Jan 6. It produced several high M flares of which three were CME related. The two sunspot groups Catania 30 and 33 (NOAA 0536 and 0537) remain flare capable next week. GEOMAGNETISM: ------------- During the whole week, the earth underwent active to minor storm conditions. The first half of the week, the Earth was under the influence of a high speed coronal hole, resulting in active to minor storm conditions. Superimposed on that, a small shock was recorded late on Jan 6. This was probably the arrival of the partial halo CME connected to the long duration M-flare (Catania 30, NOAA 0536) of Jan 5 early UT. The solar wind speed reached values of 800 km/s and the IMF pointed predominantly southward (-10nT) resulting in minor storm conditions (Kp=5) late on Jan 6. The rest of the week, a Kp=5 was reached on every day except on Jan 8. These short periods of minor storms were all due to the passage or the arrival of different CMEs. The solar wind speed oscillated between 500 km/s and 800 km/s. The two large temperature drops in the ACE data late on 8/1 and on 10/1, are clear signatures of CME arrivals. --------------------------------------------------------------------------- DAILY INDICES DATE RC 10CM Ak BKG M X 2004 Jan 05 106 123 034 C1.4 1 0 2004 Jan 06 077 117 023 B3.9 1 0 2004 Jan 07 072 119 029 B3.5 2 0 2004 Jan 08 068 120 010 B2.4 1 0 2004 Jan 09 /// 118 025 B2.3 2 0 2004 Jan 10 041 119 026 B2.6 0 0 2004 Jan 11 030 119 /// B3.7 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 5 0250 0345 0520 S10E36 M6.9 400 IV/2,III/2 30 0536 SXI derived loc, CME 6 0610 0629 0650 N04E81 M5.8 340 V/2 33 0537 SXI derived loc, halo 7 0343 0404 0421 N02E76 M4.5 2N V/2,II/1 33 0537 SXI derived loc 7 1016 1027 1033 N06E71 M8.3 SF 510 V/2,II/1 33 0537 SXI derived loc, partial halo 8 0453 0507 0521 N01E64 M1.3 1N 73 III/1 33 0537 9 0113 0122 0127 N03E49 M1.1 33 0537 9 0114 0144 0158 N02E47 M3.2 33 0537 SXI derived loc