Solar Influences Data Center (SIDC) / RWC Belgium
Royal Observatory of Belgium
E-mail: Pierre.Cugnon@oma.be
http://sidc.oma.be

SIDC WEEKLY BULLETIN
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WEEK 154 from 2003 Dec 08  

SOLAR ACTIVITY:
---------------

The flaring activity and the X-ray background were spectacularly low during the whole week. 
The X-ray background nearly vanished (see below) and up till Sunday evening, not a single C-flare 
was recorded. Just before the closing of the week however, two minor C-flares occurred 
(C1.1 at Dec 15, 19h40 UT and C2.0 at Dec 15, 23h40). The reason for this lack of any serious 
activity was the absence  -besides 2 or 3 small alpha or beta groups- of any active
region the name worthy. Instead a huge coronal hole passed the disk, which pushed the solar wind to 
a speed of more than 800 km/s. 

Two beautiful prominences erupted from the solar West limb. One in the morning of Dec 8 and the 
second one around 07h19 on Dec 14 .

There were no proton events nor halo CMEs during the period.

GEOMAGNETISM:
-------------

In contrast, the geomagnetic conditions were very disturbed as a consequence of the above
mentioned coronal hole. 

The geomagnetic conditions were at the active (Kp=4) or minor storm level (Kp=5) for most of the 
period, with isolated major storm levels (Kp=6) on Dec 8, 10 and 11.

Towards the end of the week, the space weather seemed to be changing character as the solar wind 
speed is declining and new active regions are popping up at the solar east limb. 
It thus looks like if the next week is going to be much more quiet in the magnetosphere, 
but more flaring at the Sun. 


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DAILY INDICES
DATE           RC   10CM   Ak   BKG    M   X
2003 Dec 08   ///   94   046   B1.2   0   0
2003 Dec 09   024   92   033   B1.0   0   0
2003 Dec 10   033   89   044   A8.7   0   0
2003 Dec 11   ///   86   040   A7.7   0   0
2003 Dec 12   ///   87   026   A7.4   0   0
2003 Dec 13   055   88   026   A9.7   0   0
2003 Dec 14   060   92   ///   B1.3   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)
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NOTICEABLE EVENTS
DAY BEGIN MAX  END  LOC   XRAY OP  10CM   TYPE               Cat  NOAA NOTE